International Journal of Molecular Sciences

2024

Jump to: 2023, 2022

25 pages, 19577 KiB

Open AccessReview

Applications of 2D Nanomaterials in Neural Interface

by Shuchun Gou, Siyi Yang, Yuhang Cheng, Shu Yang, Hongli Liu, Peixuan Li and Zhanhong Du

Int. J. Mol. Sci. 2024, 25(16), 8615; https://doi.org/10.3390/ijms25168615 - 7 Aug 2024

Cited by 1 | Viewed by 1259

Abstract

Neural interfaces are crucial conduits between neural tissues and external devices, enabling the recording and modulation of neural activity. However, with increasing demand, simple neural interfaces are no longer adequate to meet the requirements for precision, functionality, and safety. There are three main [...] Read more.

Neural interfaces are crucial conduits between neural tissues and external devices, enabling the recording and modulation of neural activity. However, with increasing demand, simple neural interfaces are no longer adequate to meet the requirements for precision, functionality, and safety. There are three main challenges in fabricating advanced neural interfaces: sensitivity, heat management, and biocompatibility. The electrical, chemical, and optical properties of 2D nanomaterials enhance the sensitivity of various types of neural interfaces, while the newly developed interfaces do not exhibit adverse reactions in terms of heat management and biocompatibility. Additionally, 2D nanomaterials can further improve the functionality of these interfaces, including magnetic resonance imaging (MRI) compatibility, stretchability, and drug delivery. In this review, we examine the recent applications of 2D nanomaterials in neural interfaces, focusing on their contributions to enhancing performance and functionality. Finally, we summarize the advantages and disadvantages of these nanomaterials, analyze the importance of biocompatibility testing for 2D nanomaterials, and propose that improving and developing composite material structures to enhance interface performance will continue to lead the forefront of this field. Full article

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2023

Jump to: 2024, 2022

14 pages, 4328 KiB

Open AccessArticle

Enhanced Photovoltaic Properties of Y6 Derivatives with Asymmetric Terminal Groups: A Theoretical Insight

by Yunjie Xiang, Zhijun Cao, Xiaolu Zhang, Zhuo Zou and Shaohui Zheng

Int. J. Mol. Sci. 2023, 24(19), 14753; https://doi.org/10.3390/ijms241914753 - 29 Sep 2023

Cited by 1 | Viewed by 1555

Abstract

Y6 derivatives with asymmetric terminal groups have attracted considerable attention in recent years. However, the effects of the asymmetric modification of terminal groups on the photovoltaic performance of Y6 derivatives are not well understood yet. Therefore, we designed a series of Y6-based acceptors [...] Read more.

Y6 derivatives with asymmetric terminal groups have attracted considerable attention in recent years. However, the effects of the asymmetric modification of terminal groups on the photovoltaic performance of Y6 derivatives are not well understood yet. Therefore, we designed a series of Y6-based acceptors with asymmetric terminal groups by endowing them with various electron-withdrawing abilities and different conjugated rings to conduct systematic research. The electron-withdrawing ability of the Y6-D1 terminal group (substituted by IC-2F and IC-2NO₂ terminals) is strongest, followed by Y6 (substituted by two same IC-2F terminals), Y6-D2 (substituted by IC-2F and 2-(4-oxo-4,5-dihydro-6H-cyclopenta[b]thiophen-6-ylidene)malononitrile terminals), Y6-D4 (substituted by IC-2F and indene ring), and Y6-D3 (substituted by IC-2F and thiazole ring). Computed results show that A–A stacking is the main molecular packing mode of Y6 and four other asymmetric Y6 derivatives. The ratios of A–A stacking face-on configuration of Y6-D1, Y6-D2, Y6-D3, Y6-D4, and Y6 are 51.6%, 55.0%, 43.5%, 59.3%, and 62.4%, respectively. Except for Y6-D1 substituted by the IC-2F and IC-2NO₂ (the strongest electron-withdrawing capacity) terminal groups, the other three asymmetric molecules are mainly electron-transporting and can therefore act as acceptors. The open-circuit voltages of organic solar cells (OSCs) based on Y6-D2, Y6-D3, and Y6-D4, except for Y6-D1, may be higher than those of OSCs based on the Y6 acceptor because of their higher energy levels of lowest unoccupied molecular orbital (LUMO). PM6/Y6-D3 and PM6/Y6-D4 have better light absorption properties than PM6/Y6 due to their higher total oscillator strength. These results indicate that Y6-D3 and Y6-D4 can be employed as good acceptors. Full article

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11 pages, 2458 KiB

Open AccessArticle

Thermally Reduced Graphene Oxide Membranes Revealed Selective Adsorption of Gold Ions from Mixed Ionic Solutions

by Yu Qiang, Siyan Gao, Yueyu Zhang, Shuai Wang, Liang Chen, Liuhua Mu, Haiping Fang, Jie Jiang and Xiaoling Lei

Int. J. Mol. Sci. 2023, 24(15), 12239; https://doi.org/10.3390/ijms241512239 - 31 Jul 2023

Cited by 3 | Viewed by 1881

Abstract

The recovery of gold from water is an important research area. Recent reports have highlighted the ultrahigh capacity and selective extraction of gold from electronic waste using reduced graphene oxide (rGO). Here, we made a further attempt with the thermal rGO membranes and [...] Read more.

The recovery of gold from water is an important research area. Recent reports have highlighted the ultrahigh capacity and selective extraction of gold from electronic waste using reduced graphene oxide (rGO). Here, we made a further attempt with the thermal rGO membranes and found that the thermal rGO membranes also had a similarly high adsorption efficiency (1.79 g gold per gram of rGO membranes at 1000 ppm). Furthermore, we paid special attention to the detailed selectivity between Au³⁺ and other ions by rGO membranes. The maximum adsorption capacity for Au³⁺ ions was about 16 times that of Cu²⁺ ions and 10 times that of Fe³⁺ ions in a mixture solution with equal proportions of Au³⁺/Cu²⁺ and Au³⁺/Fe³⁺. In a mixed-ion solution containing Au³⁺:Cu²⁺:Na⁺:Fe³⁺:Mg²⁺ of printed circuit board (PCB), the mass of Au³⁺:Cu²⁺:Na⁺:Fe³⁺:Mg²⁺ in rGO membranes is four orders of magnitude higher than the initial mass ratio. A theoretical analysis indicates that this selectivity may be attributed to the difference in the adsorption energy between the metal ions and the rGO membrane. The results are conducive to the usage of rGO membranes as adsorbents for Au capture from secondary metal resources in the industrial sector. Full article

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Adsorption capacity of Au3+ ions using rGO membranes. (a) Schematic diagram of the adsorption process. (b) Gold adsorption isotherms of rGO membranes after 48 h. The Au3+ adsorption capacity of rGO membranes can reach up to 1.79 g/g. Full article ">Figure 2
Excellent selective adsorption of rGO membranes to Au3+ in mixed solutions (a,b). The adsorption capacity of Au3+ ions in Au3+/Cu2+ mixed-ion solutions (100 ppm/0.5 ppm). (c,d) The adsorption capacity of Au3+ ions in Au3+/Fe3+ mixed-ion solutions (100 ppm/0.5 ppm). (e) The initial concentration ratio of the configured mixed-ion solution (denoted Ri) for Au3+:Cu2+:Na+:Fe3+:Mg2+ as Ri = 1:1000:1000:100:100, where the concentration of Au3+ was 100 ppm. (f) The adsorption capacity of 5 kinds of ions in the configured mixed-ion solution by rGO membranes. The corresponding mass ratio in the rGO membranes (denoted Rf) of Au3+:Cu2+:Na+:Fe3+:Mg2+ were Rf = 1:0.11:0.06:0.22:0.07. Full article ">Figure 3
Models of ion adsorption on graphene by DFT calculations (a–e). The optimized configuration of the adsorption of Au3+, Cu2+, Fe3+, Mg2+ and Na+ on rGO surfaces. Gray represents the C atom, while yellow, green, brown, pink and blue represent Au, Cu, Fe, Mg and Na ions, respectively. (f) Adsorption energies of various cations on the graphite surface. The absolute value of the adsorption energy of Au3+ is the largest, which is −1080.04 kcal/mol. The absolute value of the adsorption energies of the other ions from large to small are listed as Fe3+ > Cu2+ > Mg2+ > Na+. Full article ">Figure 4
Characterization experiment for rGO membranes. (a) Raman spectra of the GO, rGO and rGO-Au. The ID/IG ratios of GO, rGO and rGO-Au are 0.98, 1.06 and 0.95, respectively. (b) XRD patterns of GO and rGO membranes. There are peaks at 10.9° and 24.1° for the GO membranes and rGO membranes, respectively. (c) Full−scan X−ray photoelectron spectrometer spectra of GO and rGO membranes. The C1s and O1s peak positions of membranes were at 285.08 eV and 532.08 eV, respectively. (d) Elemental atomic content of C and O. It is obvious that the oxygen content in each sample decreased sharply, indicating the successful removal of oxygen-containing groups from the GO surface. Full article ">Figure 5
Characterization experiments of the rGO membrane after Au adsorption. (a) XRD patterns. The peak at ~24° is from the rGO membranes, and the peaks at ~38.1°, 44.4°, 64.5° and 77.5° are close to the value of 2θ for the (111), (200), (220) and (311) surface of gold, respectively. (b) XPS spectra of Au (4f), which means that the valence state of gold is 0. (c) SEM image shows that a large number of submicron particles with a diameter of about 1 μm appeared. (d) Elemental mapping of the rGO membrane after Au adsorption based on SEM analysis. The elements of C, O, Au and Cl are displayed by the colors of red, blue, yellow and green, respectively. Full article ">Figure 6
Adsorption capacity of Au3+ ions using rGO membranes. A schematic of separated Au3+ ions by rGO membranes. Full article ">

16 pages, 6080 KiB

Open AccessArticle

Increasing Charge Carrier Mobility through Modifications of Terminal Groups of Y6: A Theoretical Study

by Yunjie Xiang, Chunlin Xu and Shaohui Zheng

Int. J. Mol. Sci. 2023, 24(10), 8610; https://doi.org/10.3390/ijms24108610 - 11 May 2023

Cited by 6 | Viewed by 2170

Abstract

The applications of non-fullerene acceptor Y6 with a new type of A₁-DA₂D-A₁ framework and its derivatives have increased the power conversion efficiency (PCE) of organic solar cells (OSCs) up to 19%. Researchers have made various modifications of the [...] Read more.

The applications of non-fullerene acceptor Y6 with a new type of A₁-DA₂D-A₁ framework and its derivatives have increased the power conversion efficiency (PCE) of organic solar cells (OSCs) up to 19%. Researchers have made various modifications of the donor unit, central/terminal acceptor unit, and side alkyl chains of Y6 to study the influences on the photovoltaic properties of OSCs based on them. However, up to now, the effect of changes of terminal acceptor parts of Y6 on the photovoltaic properties is not very clear. In the present work, we have designed four new acceptors—Y6-NO₂, Y6-IN, Y6-ERHD, and Y6-CAO—with different terminal groups, which possess diverse electron-withdrawing ability. Computed results show that with the enhanced electron-withdrawing ability of the terminal group, the fundamental gaps become lower; thus, the wavelengths of the main absorption peaks of UV-Vis spectra red-shifts and total oscillator strength increase. Simultaneously, the electron mobility of Y6-NO₂, Y6-IN, and Y6-CAO is about six, four, and four times faster than that of Y6, respectively. Overall, Y6-NO₂ could be a potential NFA because of its longer intramolecular charge-transfer distance, stronger dipole moment, higher averaged ESP, enhanced spectrum, and faster electron mobility. This work provides a guideline for the future research on modification of Y6. Full article

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25 pages, 9023 KiB

Open AccessReview

Application of Biomedical Microspheres in Wound Healing

by Caihong Yang, Zhikun Zhang, Lu Gan, Lexiang Zhang, Lei Yang and Pan Wu

Int. J. Mol. Sci. 2023, 24(8), 7319; https://doi.org/10.3390/ijms24087319 - 15 Apr 2023

Cited by 29 | Viewed by 4066

Abstract

Tissue injury, one of the most common traumatic injuries in daily life, easily leads to secondary wound infections. To promote wound healing and reduce scarring, various kinds of wound dressings, such as gauze, bandages, sponges, patches, and microspheres, have been developed for wound [...] Read more.

Tissue injury, one of the most common traumatic injuries in daily life, easily leads to secondary wound infections. To promote wound healing and reduce scarring, various kinds of wound dressings, such as gauze, bandages, sponges, patches, and microspheres, have been developed for wound healing. Among them, microsphere-based tissue dressings have attracted increasing attention due to the advantage of easy to fabricate, excellent physicochemical performance and superior drug release ability. In this review, we first introduced the common methods for microspheres preparation, such as emulsification-solvent method, electrospray method, microfluidic technology as well as phase separation methods. Next, we summarized the common biomaterials for the fabrication of the microspheres including natural polymers and synthetic polymers. Then, we presented the application of the various microspheres from different processing methods in wound healing and other applications. Finally, we analyzed the limitations and discussed the future development direction of microspheres in the future. Full article

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15 pages, 3490 KiB

Open AccessArticle

Preparation of High-Toughness Lignin Phenolic Resin Biomaterials Based via Polybutylene Succinate Molecular Intercalation

by Jin Xie, Hao Sun, Yuchun Yang, Junxiong Liang, Yun Li, Defa Hou, Xu Lin, Jun Zhang, Zhengjun Shi and Can Liu

Int. J. Mol. Sci. 2023, 24(7), 6418; https://doi.org/10.3390/ijms24076418 - 29 Mar 2023

Cited by 6 | Viewed by 2372

Abstract

Lignin has many potential applications and is a biopolymer with a three-dimensional network structure. It is composed of three phenylpropane units, p-hydroxyphenyl, guaiacyl, and syringyl, connected by ether bonds and carbon–carbon bonds, and it contains a large number of phenol or aldehyde structural [...] Read more.

Lignin has many potential applications and is a biopolymer with a three-dimensional network structure. It is composed of three phenylpropane units, p-hydroxyphenyl, guaiacyl, and syringyl, connected by ether bonds and carbon–carbon bonds, and it contains a large number of phenol or aldehyde structural units, resulting in complex lignin structures. This limits the application of lignin. To expand the application range of lignin, we prepared lignin thermoplastic phenolic resins (LPRs) by using lignin instead of phenol; these LPRs had molecular weights of up to 1917 g/mol, a molecular weight distribution of 1.451, and an O/P value of up to 2.73. Due to the complex structure of the lignin, the synthetic lignin thermoplastic phenolic resins were not very tough, which greatly affected the performance of the material. If the lignin phenolic resins were toughened, their application range would be substantially expanded. Polybutylene succinate (PBS) has excellent processability and excellent mechanical properties. The toughening effects of different PBS contents in the LPRs were investigated. PBS was found to be compatible with the LPRs, and the flexible chain segments of the small PBS molecules were embedded in the molecular chain segments of the LPRs, thus reducing the crystallinities of the LPRs. The good compatibility between the two materials promoted hydrogen bond formation between the PBS and LPRs. Rheological data showed good interfacial bonding between the materials, and the modulus of the high-melting PBS made the LPRs more damage resistant. When PBS was added at 30%, the tensile strength of the LPRs was increased by 2.8 times to 1.65 MPa, and the elongation at break increased by 31 times to 93%. This work demonstrates the potential of lignin thermoplastic phenolic resins for industrial applications and provides novel concepts for toughening biobased aromatic resins with PBS. Full article

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11 pages, 2204 KiB

Open AccessArticle

Polypyrrole-Stabilized Polypeptide for Eco-Friendly Supercapacitors

by Zhe Li, Kuan Hu, Zhou Li, Cong Li and Yulin Deng

Int. J. Mol. Sci. 2023, 24(3), 2497; https://doi.org/10.3390/ijms24032497 - 27 Jan 2023

Cited by 3 | Viewed by 2272

Abstract

As an energy storage technology, supercapacitors (SCs) have become an important part of many electronic systems because of their high-power density, long cycle life, and maintenance-free characteristics. However, the widespread development and use of electronics, including SCs, have led to the generation of [...] Read more.

As an energy storage technology, supercapacitors (SCs) have become an important part of many electronic systems because of their high-power density, long cycle life, and maintenance-free characteristics. However, the widespread development and use of electronics, including SCs, have led to the generation of a large amount of e-waste. In addition, achieving compatibility between stability and biodegradability has been a prominent challenge for implantable electronics. Therefore, environmentally friendly SCs based on polypyrrole (PPy)-stabilized polypeptide (FF) are demonstrated in this study. The fully degradable SC has a layer-by-layer structure, including polylactic acid/chitosan (PLA–C) support layers, current collectors (Mg), FF/PPy composite layers, and a polyvinyl alcohol/phosphate buffer solution (PVA/PBS) hydrogel. It has the advantages of being light, thin, flexible, and biocompatible. After 5000 cycles in air, the capacitance retention remains at up to 94.7%. The device could stably operate for 7 days in a liquid environment and completely degrade in vitro within 90 days without any adverse effect on the environment. This work has important implications for eco-friendly electronics and will have a significant impact on the implantable biomedical electronics. Full article

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Schematic illustration of degradable supercapacitor (a) and the fabrication of FF/PPy (b) and FF–Py copolymer (c) films. Full article ">Figure 2
Characterization and electrochemical property of PPy, FF, FF/PPy, and FF–Py copolymer. (a) SEM images; (b) FTIR spectrum; (c) Raman spectrum; (d) XRD pattern. Full article ">Figure 3
Electrochemical performance of all-solid SCs based on FF films, FF/PPy film with 150 cycles of PPy deposition, and FF–Py copolymer films with a ratio of 1:1. (a) Structure schematic of the FF/PPy-based SCs; (b–d) CV curves of FF/PPy-based SCs (b) and the SCs using FF–Py copolymer film (c) at different scan rates, respectively; (d) comparison of SCs based on FF, FF/PPy, and FF–Py copolymer films; (e) GCD curves of FF/PPy-based SCs at different current densities; (f) GCD curves of the SCs using FF–Py copolymer film at different current densities; (g) mass specific capacitances variation of SCs based on FF/PPy and FF–Py copolymer films with different scan rates; (h) Nyquist plot reflecting the impedance characteristics of SCs; (i) cycle stability test with the current density of 0.2 mA·cm−2 at 0.8 V. Full article ">Figure 4
Capacitive performance and biodegradability of SCs in the liquid environment in vitro. Electrochemical performance test of SCs for a short-term in PBS at 37 °C (a–c). The current density in (b) is 0. 2 mA·cm−2; (c) the variation of mass specific capacitance during device’s degradation; (d) in vitro degradation of SCs in 1× PBS buffer in a cell culture dish (inner diameter: 35 mm) at room temperature; (e) the mass variation of SCs during degradation; (f) biocompatibility of SCs. Attachment, proliferation, and morphology of the L929 cells at different times. Scale bars: 100 µm; (g) the viabilities of L929 cells after being cultured for 3 days. All data are presented as the mean ± SD. Full article ">

10 pages, 1939 KiB

Open AccessArticle

Tailored Supramolecular Cage for Efficient Bio-Labeling

by Dongdong An, Linlin Shi, Tianyu Li, Hong-Yu Zhang, Yahong Chen, Xin-Qi Hao and Mao-Ping Song

Int. J. Mol. Sci. 2023, 24(3), 2147; https://doi.org/10.3390/ijms24032147 - 21 Jan 2023

Cited by 2 | Viewed by 1941

Abstract

Fluorescent chemosensors are powerful imaging tools used in a broad range of biomedical fields. However, the application of fluorescent dyes in bioimaging still remains challenging, with small Stokes shifts, interfering signals, background noise, and self-quenching on current microscope configurations. In this work, we [...] Read more.

Fluorescent chemosensors are powerful imaging tools used in a broad range of biomedical fields. However, the application of fluorescent dyes in bioimaging still remains challenging, with small Stokes shifts, interfering signals, background noise, and self-quenching on current microscope configurations. In this work, we reported a supramolecular cage (C_A) by coordination-driven self-assembly of benzothiadiazole derivatives and Eu(OTf)₃. The C_A exhibited high fluorescence with a quantum yield (QY) of 38.57%, good photoluminescence (PL) stability, and a large Stokes shift (153 nm). Furthermore, the CCK-8 assay against U87 glioblastoma cells verified the low cytotoxicity of C_A. We revealed that the designed probes could be used as U87 cells targeting bioimaging. Full article

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The preparation and characterization of CA. Full article ">Figure 2
(a) The structure of L-B. (b) 1H NMR spectra (600 MHz, CD3CN/CDCl3 = 1:1), 298 K) of L-B (the solubility of L-B in CD3CN was poor, and CDCl3 was added to help dissolve). (c) 1H NMR spectra (600 MHz, CD3CN, 298 K) of CA [the yellow five-pointed star label indicates the solvent peak]. (d) ESI-MS spectra of CA and showing the observed z = +6 charge for the peak at m/z = 414.11 (bottom) compared to the theoretical isotopic pattern (top). Full article ">Figure 3
Energy-minimized molecular model of CA (Eu, green; N: blue; S, yellow; O, red; C, gray). Hydrogens, counteranions are omitted for clarity; (a) side view and (b) top view. (c) TEM images of CA. Full article ">Figure 4
Optical properties of CA in acetonitrile. (a) PLE and PL emission spectra of CA (c = 50 μg/mL). (b) Time-resolved decay spectra of CA (c = 50 μg/mL). The data were collected at an emission peak of 553 nm (λex = 400 nm). (c) Variable concentration PL spectra of CA. (d) PL photostability tests of CA (c = 50 μg/mL, λex = 400 nm λem = 537 nm). The samples were treated with the irradiation of a 400 nm blue light. Full article ">Figure 5
(a) In vitro U87 cytotoxicity profiles of CA. Mean values and error bars were defined as mean and s.d., respectively. Experiments were performed in triplicate. (b) CLSM images of viable cell distributions after co-incubation with CA at varied concentrations: 0, 25, and 50 μg/mL for 4 h. Full article ">Scheme 1
Synthesis of ligand (L-B) and self-assembly of metal-organic cage (CA). Full article ">

12 pages, 3073 KiB

Open AccessArticle

Shape-Memory-Reduced Graphene/Chitosan Cryogels for Non-Compressible Wounds

by Hongyun Xuan, Qian Du, Ruimeng Li, Xiaoni Shen, Jiao Zhou, Biyun Li, Yan Jin and Huihua Yuan

Int. J. Mol. Sci. 2023, 24(2), 1389; https://doi.org/10.3390/ijms24021389 - 10 Jan 2023

Cited by 8 | Viewed by 2580

Abstract

In this study, an antibacterial and shape-memory chitosan cryogel with high blood absorption and fast recovery from non-compressible wounds was prepared using a one-step method. Herein, we prepared a shape-memory-reduced graphene/chitosan (rGO-CTS) cryogel using a one-step method with a frozen mixing solution of [...] Read more.

In this study, an antibacterial and shape-memory chitosan cryogel with high blood absorption and fast recovery from non-compressible wounds was prepared using a one-step method. Herein, we prepared a shape-memory-reduced graphene/chitosan (rGO-CTS) cryogel using a one-step method with a frozen mixing solution of chitosan, citric acid, dopamine, and graphene oxide, before treating it with alkaline solutions. The alkaline solution not only promoted the double cross-linking of chitosan but also induced dopamine to form polydopamine-reducing graphene oxide. Scanning electron microscope (SEM) images showed that the rGO-CTS cryogel possessed a uniform porous network structure, attributing excellent water-induced shape-memory properties. Moreover, the rGO-CTS cryogel exhibited good mechanical properties, antibacterial activity, and biocompatibility. In mouse liver trauma models, the rGO-CTS cryogel showed good blood clotting and hemostatic capabilities. Therefore, this composite cryogel has great potential as a new hemostatic material for application to non-compressible wounds. Full article

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18 pages, 5415 KiB

Open AccessArticle

A Multifunctional Dental Resin Composite with Sr-N-Doped TiO₂ and n-HA Fillers for Antibacterial and Mineralization Effects

by Yuanhang Zhao, Hong Zhang, Lihua Hong, Xinying Zou, Jiazhuo Song, Rong Han, Jiawen Chen, Yiyan Yu, Xin Liu, Hong Zhao and Zhimin Zhang

Int. J. Mol. Sci. 2023, 24(2), 1274; https://doi.org/10.3390/ijms24021274 - 9 Jan 2023

Cited by 7 | Viewed by 2491

Abstract

Dental caries, particularly secondary caries, which is the main contributor to dental repair failure, has been the subject of extensive research due to its biofilm-mediated, sugar-driven, multifactorial, and dynamic characteristics. The clinical utility of restorations is improved by cleaning bacteria nearby and remineralizing [...] Read more.

Dental caries, particularly secondary caries, which is the main contributor to dental repair failure, has been the subject of extensive research due to its biofilm-mediated, sugar-driven, multifactorial, and dynamic characteristics. The clinical utility of restorations is improved by cleaning bacteria nearby and remineralizing marginal crevices. In this study, a novel multifunctional dental resin composite (DRC) composed of Sr-N-co-doped titanium dioxide (Sr-N-TiO₂) nanoparticles and nano-hydroxyapatite (n-HA) reinforcing fillers with improved antibacterial and mineralization properties is proposed. The experimental results showed that the anatase-phase Sr-N-TiO₂ nanoparticles were synthesized successfully. After this, the curing depth (CD) of the DRC was measured from 4.36 ± 0.18 mm to 5.10 ± 0.19 mm, which met the clinical treatment needs. The maximum antibacterial rate against Streptococcus mutans (S. mutans) was 98.96%, showing significant inhibition effects (p < 0.0001), which was experimentally verified to be derived from reactive oxygen species (ROS). Meanwhile, the resin exhibited excellent self-remineralization behavior in an SBF solution, and the molar ratio of Ca/P was close to that of HA. Moreover, the relative growth rate (RGR) of mouse fibroblast L929 indicated a high biocompatibility, with the cytotoxicity level being 0 or I. Therefore, our research provides a suitable approach for improving the antibacterial and mineralization properties of DRCs. Full article

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Characterization of Sr-N-TiO2 nanoparticles. (A) Field emission scanning electron microscope (FE-SEM) micrographs; (B,C) transmission electron microscopy (TEM) micrograph of the Sr-N-TiO2 powders. (D) High-angle annular dark field (HAADF) image and (E) Energy-dispersive X-ray spectroscopy (EDS) spectrum of Ti, O, Sr, and N elements in Sr-N-TiO2. (F,G) X-ray photoelectron spectroscopy (XPS) pattern. (H) X-ray diffraction (XRD) pattern, (I) Raman spectra, and (J) UV–Vis absorption spectra of synthesized Sr-N-TiO2 and TiO2. Full article ">Figure 2
Physicochemical properties of DRs. (A) FT-IR spectra between 1750 cm−1 and 1600 cm−1 (the arrows show the absorbance peaks at 1636 cm−1 of C=C and 1720 cm−1 of C=O) and the DC rate with curing for (B) 20 s, (C) 40 s, (D) 60 s in each group. (E) CD at curing for 20 s. (F,G) Water contact angle (WCA) of 5 μL deionized water on the DRC surface. * p < 0.05, ** p < 0.01, *** p < 0.001, and **** p < 0.0001. Full article ">Figure 3
Antibacterial properties and antibacterial mechanism of DRCs. (A,B) Colony-forming units (CFU) counting. a: 0% Group, b: 2.5% Group, c: 5% Group, d: 7.5% Group. (C) Crystal violet staining assay. (D) The characteristic peak of DPBF at 410 nm under LED light for 0, 1, 3, and 5 min. (E,F) CFU counting with NAC. Blank group (BHI), the negative group (NAC), the positive group (Sr-N-TiO2), and the experimental group (NAC and Sr-N-TiO2). a: 0% Group, b: 2.5% Group, c: 5% Group, d: 7.5% Group. (G) SEM image of the bacteria on the surface; a: 0% Group, b: 2.5% Group, c: 5% Group, d: 7.5% Group. The yellow arrows show the unusual bacteria. **** p < 0.0001. Full article ">Figure 4
Live/dead staining of bacterial biofilm on DRCs’ surface. (A) 0% group, (B) 2.5% group, (C) 5% group, (D) 7.5% group. The damaged bacteria were stained red by PI dye, and the living bacteria were stained green by SYTO 9 dye. Full article ">Figure 5
The morphological surface alterations and element quantification of (A–D) 14 d and (E–H) 28 d using an FE-SEM with EDS. (A,E) 0% group, (B,F) 2.5% group, (C,G) 5% group, (D,H) 7.5% group. The Ca/P ratios are labeled in the EDS figures. Full article ">

2022

Jump to: 2024, 2023

12 pages, 2010 KiB

Open AccessArticle

Three Different Interaction Patterns between MCM-41 and Proteins

by Yuke Xie, Ziqiao Zhong, Wenhao Wang, Ying Huang, Chuanbin Wu, Xin Pan and Zhengwei Huang

Int. J. Mol. Sci. 2022, 23(24), 15850; https://doi.org/10.3390/ijms232415850 - 13 Dec 2022

Viewed by 1621

Abstract

As one of the most studied mesoporous silica nanoparticles (MSNs) in drug delivery systems, Mobil Composition of Matter No. 41 (MCM-41) possesses unique properties including perfect channel architecture, excellent load capacity, and good biocompatibility. However, the applications of MCM-41 nanoparticles in drug delivery [...] Read more.

As one of the most studied mesoporous silica nanoparticles (MSNs) in drug delivery systems, Mobil Composition of Matter No. 41 (MCM-41) possesses unique properties including perfect channel architecture, excellent load capacity, and good biocompatibility. However, the applications of MCM-41 nanoparticles in drug delivery have not yet been industrialized, due to the interaction between MCM-41 and biomolecules (especially proteins) that affect their in vivo behaviors after dosing. To investigate the interactions between MCM-41 and proteins, this study selected bovine serum albumin (BSA), lysozyme (Lyso), and bovine hemoglobin (BHb) as model proteins and characterized the ultraviolet-visible, fluorescence, circular dichroism spectra and the protein adsorption of MCM-41-protein complex. The UV-Vis spectra exhibited the different absorption increment degrees of three proteins. The fluorescence spectra showed that the fluorescence intensity of proteins changed by different trends. The CD spectra indicated that the secondary structure changes were ranked as BSA > Lyso > BHb, which is consistent with the protein’s adsorption capability on MCM-41. It was shown that there were three different patterns of MCM-41-proteins interactions. The hydrophilic and low-charged BSA followed the strong interaction pattern, the hydrophilic but heavily charged Lyso followed the moderate interaction pattern, and the hydrophobic BHb followed the weak interaction pattern. Different interaction patterns would lead to different effects on the structural properties of proteins, the surface chemistry of MCM-41, and the absorption capability of proteins on MCM-41. We believe our study will provide a better insight into the application of MCM-41 nanoparticles in drug delivery systems. Full article

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Particle size (column) and PDI (line) of MCM-41 nanoparticles with different ultrasonication times. Full article ">Figure 2
(A–C) UV-Vis spectra of MCM-41 incubated with BSA (A), Lyso (B) and BHb (C). (D–F) The normalized UV spectra: BSA (D), Lyso (E) and BHb (F). (G) The Abs increment of MCM-41 was incubated with different proteins. (H) The percentage of Abs intensity increment of different proteins incubated with MCM-41. (I) The Δwavelength of different proteins incubated with MCM-41. Full article ">Figure 3
(A–C) Fluorescence spectra of MCM-41 incubated with BSA (A), Lyso (B) and BHb (C). (D) The fluorescence intensity increments of different proteins which were incubated with MCM-41. (E) The percentage of fluorescence intensity increment of different proteins incubated with MCM-41. (F) The Δemission of different proteins incubated with MCM-41. Full article ">Figure 4
(A–C) CD spectra of MCM-41 incubated with BSA (A), Lyso (B) and BHb (C). (D) The CD ellipticity values at 208 nm of different proteins incubated with MCM-41. (E) The changes of α-helix and other secondary structures’ contents of different proteins incubated with MCM-41. Full article ">Figure 5
The adsorption amount of different proteins on MCM-41 at different concentrations. Full article ">Figure 6
(A) The strong interaction pattern. (B) The moderate interaction pattern. (C) The weak interaction pattern. Full article ">

14 pages, 3483 KiB

Open AccessArticle

Synthesis of a Tetrahedral Metal–Organic Supramolecular Cage with Dendritic Carbazole Arms

by Juanzi Lianglu, Weinan Hu, Xinju Zhu, Hong-Yu Zhang, Linlin Shi, Xin-Qi Hao and Mao-Ping Song

Int. J. Mol. Sci. 2022, 23(24), 15580; https://doi.org/10.3390/ijms232415580 - 8 Dec 2022

Cited by 2 | Viewed by 2105

Abstract

In recent years, incredible endeavors have been devoted to the design and self-assembly of discrete metal–organic cages (MOCs) with expanding intricacy and functionality. The controlled synthesis of metal–organic supramolecular cages with large branched chains remains an interesting and challenging work in supramolecular chemistry. [...] Read more.

In recent years, incredible endeavors have been devoted to the design and self-assembly of discrete metal–organic cages (MOCs) with expanding intricacy and functionality. The controlled synthesis of metal–organic supramolecular cages with large branched chains remains an interesting and challenging work in supramolecular chemistry. Herein, a tetrahedral metal–organic supramolecular cage (Zn^II₄L₄) containing 12 dendritic carbazole arms is unprecedentedly constructed through coordination-driven subcomponent self-assembly and characterized in different ways. Interestingly, tetrahedral supramolecular Cage-1 exhibited the potential for aggregation-induced emission (AIE) performance and stimulus-responsive luminescence features, and it achieved color-tunable photoluminescence due to the introduction of dendritic carbazole arms. Crucially, owing to the great photophysical properties of Cage-1 in solution, Cage-1 was enabled to act as a fluorescent ink for the vapor-responsive recording and wiping of information. Full article

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(a) The structure of Cage-1; (b) 1H NMR (CD3CN: CDCl3 = 1:1, 600 MHz, 298 K) spectrum of ligand LA; (c) 1H NMR (CD3CN: CDCl3 = 1:1, 600 MHz, 298 K) spectrum of Cage-1; (d) 1H NMR (CD3CN, 600 MHZ, 298 K) spectrum of ligand LB. Full article ">Figure 2
(a) ESI-MS spectra of Cage-1; (b) 2D DOSY spectrum of Cage-1. Full article ">Figure 3
(a) The structure of Cage-1; (b) The structure of Cage-2; (c) 1H NMR (CD3CN: CDCl3 = 1:1, 600 MHz, 298 K) spectrum of Cage-1; (d) 1H NMR (CD3CN, 600 MHz, 298 K) spectrum of Cage-2. Full article ">Figure 4
(a) Energy-minimized molecular structure of Cage-1 (Zn, yellow; N, blue; O, red; C, gray). Hydrogens and counteranions are omitted for clarity ((a) side view and (b) top view of Cage-1). Full article ">Figure 5
(a) Fluorescence emission spectra of ligand LA in varying proportions of chloroform–ethyl ether solvent mixture; (b) Fluorescence intensity of ligand LA at 340 nm in the varying proportions of chloroform–ethyl ether solvent mixture (c = 1.0 × 10−6 M, λex = 340 nm, Slit = 3, 3). Full article ">Figure 6
(a) Fluorescence emission spectra of Cage-1 in the varying proportions of acetone–ethyl ether solvent mixture; (b) Fluorescence intensity of Cage-1 at 340 nm in the varying proportions of acetone–ethyl ether solvent mixture (c = 1.0 × 10−6 M, λex = 340 nm, Slit = 2, 2). Full article ">Figure 7
Vapor-responsive information recognition of Cage-1. Full article ">Scheme 1
(a) The synthesis of ligand LA; (b) The synthesis of ligand LB; (c) The crystal structure of ligand LA. Full article ">Scheme 2
The synthesis of Cage-1. Full article ">

15 pages, 3205 KiB

Open AccessArticle

One-Step Pyrolysis of Nitrogen-Containing Chemicals and Biochar Derived from Walnut Shells to Absorb Polycyclic Aromatic Hydrocarbons (PAHs)

by Wendong Wang, Donghua Li, Ping Xiang, Yunwu Zheng, Zhifeng Zheng, Xu Lin, Xiahong He and Can Liu

Int. J. Mol. Sci. 2022, 23(23), 15193; https://doi.org/10.3390/ijms232315193 - 2 Dec 2022

Cited by 9 | Viewed by 1989

Abstract

The pyrolysis of biomass is an efficient means of utilizing biomass resources. Biomass can be converted into various high-performance chemicals and functional materials through pyrolysis. However, current pyrolysis technologies suffer from low conversion rates and single products, so the preparation of nitrogen compounds [...] Read more.

The pyrolysis of biomass is an efficient means of utilizing biomass resources. Biomass can be converted into various high-performance chemicals and functional materials through pyrolysis. However, current pyrolysis technologies suffer from low conversion rates and single products, so the preparation of nitrogen compounds with high economic value remains a challenge. The walnut shell was soaked in three nitrogen-containing compound solutions before carbonization to produce high-value-added nitrogen-containing chemicals (with a nitrogen content of 59.09%) and biochar for the adsorption of polycyclic aromatic hydrocarbons (PAHs). According to biochar analysis, biochar has a porous structure with a specific surface area of 1161.30 m²/g and a high level of rocky desertification. The surface forms a dense pyrrole structure, and the structure produces π–π interactions with naphthalene molecules, exhibiting excellent naphthalene adsorption with a maximum capacity of 214.98 mg/g. This study provides an efficient, rapid, and environmentally friendly method for producing nitrogen-containing chemicals with high-added value and biochar. Full article

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13 pages, 6389 KiB

Open AccessArticle

Dynamic Double Cross-Linked Self-Healing Polysaccharide Hydrogel Wound Dressing Based on Schiff Base and Thiol-Alkynone Reactions

by Zhuojun Zhang, Jiasen Bu, Biyun Li, Hongyun Xuan, Yan Jin and Huihua Yuan

Int. J. Mol. Sci. 2022, 23(22), 13817; https://doi.org/10.3390/ijms232213817 - 10 Nov 2022

Cited by 13 | Viewed by 2887

Abstract

In this study, a hydrogel composite wound dressing with antibacterial and self-healing ability was prepared using cysteine-modified carboxymethyl chitosan, sodium oxidized alginate, and but-3-yn-2-one base on Schiff base and thiol-alkynone double cross-links. The structure and properties of the hydrogel were characterized by scanning [...] Read more.

In this study, a hydrogel composite wound dressing with antibacterial and self-healing ability was prepared using cysteine-modified carboxymethyl chitosan, sodium oxidized alginate, and but-3-yn-2-one base on Schiff base and thiol-alkynone double cross-links. The structure and properties of the hydrogel were characterized by scanning electron microscope, Fourier-transform infrared, and rheological test, followed by antibacterial and in vivo biocompatibility tests. The results showed that the hydrogel exhibited good self-healing, mechanical properties, good antibacterial effect, and in vivo biocompatibility, and can inhibit inflammation and promote skin tissue regeneration in mice. This novel self-healing hydrogel dressing has a broad application prospect in skin tissue engineering. Full article

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(a) OSA synthetic route; (b) CMCS graft Cys synthesis route; (c) Dynamic thiol-alkynone double addition; (d) SH-CMCS/OSA hydrogel-forming gels. Full article ">Figure 2
(a) Schematic diagram of self-healing hydrogel; (b) SEM diagram of SH-CMCS/OSA hydrogel; (c) FTIR of hydrogel; and (d) 1H NMR of CMCS, Cys and SH-CMCS. Full article ">Figure 3
(a) Gelation time of SH-CMCS/OSA hydrogel at different but-3-yn-2-one concentrations; (b) Gelation time change of SH-CMCS/OSA hydrogel at different but-3-yn-2-one concentrations; (c) Maximum strain analysis of hydrogels with but-3-yn-2-one concentration of 5 μL/mL; (d) Rheological analysis of hydrogel at 5 μL/mL but-3-yn-2-one concentration. Full article ">Figure 4
Live/dead staining of L929 cells that were treated with TCP or hydrogel for 24 h and 48 h. Full article ">Figure 5
(a,b) Effect of the hydrogel on the growth of E. coli and S. aureus. (c,d) Effect of hydrogel on ROS content of E. coli and S. aureus (** p < 0.01). Full article ">Figure 6
Mice skin sections stained with H&E on days 7 and 14 of (a) Hydrogel + bacteria; (b) Hydrogel-only; (c) SPSS; (d) Bacteria-only. (black arrows indicate inflammatory cells). Full article ">

16 pages, 9708 KiB

Open AccessArticle

Quantitative Analysis of Acetone in Transformer Oil Based on ZnO NPs@Ag NWs SERS Substrates Combined with a Stoichiometric Model

by Xinyuan Zhang, Yu Lei, Ruimin Song, Weigen Chen, Changding Wang, Ziyi Wang, Zhixian Yin and Fu Wan

Int. J. Mol. Sci. 2022, 23(21), 13633; https://doi.org/10.3390/ijms232113633 - 7 Nov 2022

Cited by 2 | Viewed by 2225

Abstract

Acetone is an essential indicator for determining the aging of transformer insulation. Rapid, sensitive, and accurate quantification of acetone in transformer oil is highly significant in assessing the aging of oil-paper insulation systems. In this study, silver nanowires modified with small zinc oxide [...] Read more.

Acetone is an essential indicator for determining the aging of transformer insulation. Rapid, sensitive, and accurate quantification of acetone in transformer oil is highly significant in assessing the aging of oil-paper insulation systems. In this study, silver nanowires modified with small zinc oxide nanoparticles (ZnO NPs@Ag NWs) were excellent surface-enhanced Raman scattering (SERS) substrates and efficiently and sensitively detected acetone in transformer oil. Stoichiometric models such as multiple linear regression (MLR) models and partial least square regressions (PLS) were investigated to quantify acetone in transformer oil and compared with commonly used univariate linear regressions (ULR). PLS combined with a preprocessing algorithm provided the best prediction model, with a correlation coefficient of 0.998251 for the calibration set, 0.997678 for the predictive set, a root mean square error in the calibration set (RMSECV = 0.12596 mg/g), and a prediction set (RMSEP = 0.11408 mg/g). For an acetone solution of 0.003 mg/g, the mean absolute percentage error (MAPE) was the lowest among the three quantitative models. For a concentration of 7.29 mg/g, the MAPE was 1.60%. This method achieved limits of quantification and detections of 0.003 mg/g and 1 μg/g, respectively. In general, these results suggested that ZnO NPs@Ag NWs as SERS substrates coupled with PLS simply and accurately quantified trace acetone concentrations in transformer oil. Full article

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Characterization of ZnO NPs@Ag NWs (0.02 g) by transmission electron microscopy. TEM (a), HAADF-STEM (b), EDS mapping images (c–e), HRTEM (f), EDS spectrum (g), and SAED pattern (h) of ZnO NPs@Ag NWs (0.02 g). Full article ">Figure 2
XRD patterns of Ag NWs and ZnO NPs@Ag NWs. Full article ">Figure 3
(a) XPS of ZnO NPs@Ag NWs. (b–d) High-resolution XPS spectra of Ag 3d, Zn 2p, and O 1s. Full article ">Figure 4
(a) SEM images of Ag NWs, and the inset shows the diameter distribution of Ag NWs. (b–d) SEM images of ZnO NPs@Ag NWs (0.005, 0.02, and 0.2 g), and the insets are the particle size distribution of the loaded ZnO NPs. (e) SERS spectra of 10−6 M R6G adsorbed on Ag NWs, ZnO NPs@Ag NWs, and ZnO. (f) Dependence of the peak intensity value at 1649 cm−1 with various ZnCl2. Full article ">Figure 5
SERS spectra of R6G at a concentration of 10−6 to 10−9 M (a) and 10−10 to 10−12 M (b). SERS spectra (c) and uniformity (d) of 10−6 M R6G on ZnO NPs@Ag NWs at 20 random positions. Full article ">Figure 6
SERS spectra: long-term stability of 10−6 M R6G on Ag NWs (a,b) and ZnO NPs@Ag NWs (c,d) was measured every two days during one month at room temperature. Full article ">Figure 7
(a) Raman spectra of ZnO NPs@Ag NWs substrates, pure water, acetone, acetone extract (extractant was pure water), and acetone extract enhanced by ZnO NPs@Ag NWs. (b) SERS spectra of different acetone extract concentrations (the inset shows the local magnifications of 0.09, 0.03, 0.01, and 0.003 mg/g). Full article ">Figure 8
Analytical results of models. Scatter plots of predicted concentration (log3 (mg·g−1)) vs. actual concentration (log3 (mg·g−1)) for ULR (a), MLR (b), and PLS (d) models. (c) RMSECV vs. PLS components for the PLS model. Full article ">

15 pages, 3477 KiB

Open AccessArticle

Sensitive Determination of Trace 4-Nitrophenol in Ambient Environment Using a Glassy Carbon Electrode Modified with Formamide-Converted Nitrogen-Doped Carbon Materials

by Bing Wang, Quanguo He, Guangli Li, Yaohang Long, Gongyou Zhang, Hongmei Liu and Jun Liu

Int. J. Mol. Sci. 2022, 23(20), 12182; https://doi.org/10.3390/ijms232012182 - 12 Oct 2022

Cited by 15 | Viewed by 2149

Abstract

Sensing trace amounts of 4-nitrophenol (4-NP) as a harmful substance to organisms even in small quantities is of great importance. The present study includes a sensitive and selective electrochemical sensor for detecting 4-NP in natural water samples using formamide-converted nitrogen-carbon materials (shortened to [...] Read more.

Sensing trace amounts of 4-nitrophenol (4-NP) as a harmful substance to organisms even in small quantities is of great importance. The present study includes a sensitive and selective electrochemical sensor for detecting 4-NP in natural water samples using formamide-converted nitrogen-carbon materials (shortened to f-NC) as a new material for electrode modification. The structure and morphology of the f-NC were set apart by SEM, TEM, XRD, XPS, FTIR, Raman, and the electrochemical performance of the f-NC were set apart by CV, EIS and CC. We studied the electrochemical behaviour of 4-NP on the glassy carbon electrode modified with f-NC before and after pyrolysis treatment (denoted as f-NC1/GCE and f-NC2/GCE). In 0.2 M of H₂SO₄ solution, the f-NC2/GCE has an apparent electrocatalytic activity to reduce 4-NP. Under the optimal conditions, the reduction peak current of 4-NP varies linearly, with its concentration in the range of 0.2 to 100 mM, and the detection limit obtained as 0.02 mM (S/N = 3). In addition, the electrochemical sensor has high selectivity, and the stability is quite good. The preparation and application of the sensor to detect 4-NP in water samples produced satisfactory results, which provides a new method for the simple, sensitive and quantitative detection of 4-NP. Full article

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12 pages, 5962 KiB

Open AccessArticle

Preparation of Multicolour Solid Fluorescent Carbon Dots for Light-Emitting Diodes Using Phenylethylamine as a Co-Carbonization Agent

by Yulong An, Can Liu, Yan Li, Menglin Chen, Yunwu Zheng, Hao Tian, Rui Shi, Xiahong He and Xu Lin

Int. J. Mol. Sci. 2022, 23(19), 11071; https://doi.org/10.3390/ijms231911071 - 21 Sep 2022

Cited by 10 | Viewed by 2325

Abstract

Carbon dots (CDs), as a new type of photoluminescent nanomaterial, have attracted extensive attention in various fields because of their unique luminescence properties. However, CDs will exhibit fluorescence quenching in the solid state or aggregate state, which limits their application. In this paper, [...] Read more.

Carbon dots (CDs), as a new type of photoluminescent nanomaterial, have attracted extensive attention in various fields because of their unique luminescence properties. However, CDs will exhibit fluorescence quenching in the solid state or aggregate state, which limits their application. In this paper, a unique strategy is proposed to regulate solutions to achieve multicolour fluorescence of CDs in the solid state. We report the successful preparation of orange, green and blue solid fluorescent CDs using citric acid, urea and phenylethylamine as precursors and methanol, ethanol and water as solvents, respectively. The solid-state fluorescence of CDs may be caused by the linkage of the phenylethyl structure to the surface of CDs during formation, which effectively disperses the CDs and prevents π–π interactions between graphitized nuclei. Meanwhile, multicolour solid fluorescent CDs are realized by adjusting the solvent in the preparation process. Based on the excellent fluorescence properties of CDs, orange, green and blue light-emitting diodes (LEDs) are prepared. A white LED (WLED) can be obtained by mixing the three colours of solid fluorescent CDs, which shows the application potential of CDs in display lighting equipment. Full article

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(a) Schematic illustration of the preparation of solid-state fluorescent CDs. (b) Actual photos of fluorescent CDs with different colour emissions. (c) 1H NMR spectra of CDs in CD3OD. Full article ">Figure 2
(a–c) TEM images of O-CDs, G-CDs and B-CDs. Insets: particle size distribution. (d–f) HRTEM images of O-CDs, G-CDs and B-CDs. Full article ">Figure 3
UV/vis absorption spectra of O-CDs, G-CDs, and B-CDs in ethanol solution (c = 0.1 mg/mL). Full article ">Figure 4
(a–c) Excitation, emission and (d–f) 3D spectra of O-CDs, G-CDs and B-CDs in ethanol solution (c = 0.1 mg/mL). (g–i) PL spectra of O-CDs, G-CDs and B-CDs in the solid state. Full article ">Figure 5
Fluorescence lifetime characterization of O-CDs, G-CDs and B-CDs in ethanol solution (c = 0.1 mg/mL) (a) and in the solid state (b). Full article ">Figure 6
(a) FTIR spectra of CDs. (b) XPS survey spectra and (c–e) high-resolution C1s and O1s spectra of CDs. Full article ">Figure 7
Schematic diagram of the solid-state fluorescence mechanism of CDs. Full article ">Figure 8
(a–d) EL emission spectra of the (a) O-LED, (b) G-LED, (c) B-LED and (d) WLED. The insets show optical images of the LEDs in the “off” (top) and “on” (bottom) states. Note: The color change in the picture corresponds to the dispersion spectrum of visible light at the corresponding wavelength. (e) CIE 1931 diagram containing the colour coordinates of the O-LED, G-LED, B-LED and WLED devices. Full article ">

16 pages, 3699 KiB

Open AccessArticle

β-Cyclodextrin-Based Supramolecular Imprinted Fiber Array for Highly Selective Detection of Parabens

by Zhimin Liu, Qingqing Zhou, Dan Wang, Yunli Duan, Xuehua Zhang, Yi Yang and Zhigang Xu

Int. J. Mol. Sci. 2022, 23(18), 10753; https://doi.org/10.3390/ijms231810753 - 15 Sep 2022

Cited by 3 | Viewed by 1835

Abstract

A novel high-throughput array analytical platform based on derived β-cyclodextrin supramolecular imprinted polymer (SMIP) fibers was constructed to achieve selective enrichment and removal of parabens. SMIP fiber arrays have abundant imprinting sites and introduce the host–guest inclusion effect of the derived β-cyclodextrin, which [...] Read more.

A novel high-throughput array analytical platform based on derived β-cyclodextrin supramolecular imprinted polymer (SMIP) fibers was constructed to achieve selective enrichment and removal of parabens. SMIP fiber arrays have abundant imprinting sites and introduce the host–guest inclusion effect of the derived β-cyclodextrin, which is beneficial to significantly improve the adsorption ability of fiber for parabens. Upon combination with HPLC, a specific and sensitive recognition method was developed with a low limit of detection (0.003–0.02 µg/L, S/N = 3) for parabens analysis in environmental water. This method has a good linearity (R > 0.9994) in the linear range of 0.01–200 µg/L. The proposed SMIP fiber array with high-throughput adsorption capacity has great potential in monitoring water pollution, which also provides a reliable reference for the analysis of more categories of pharmaceutical and personal care product pollutants. Full article

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16 pages, 2910 KiB

Open AccessArticle

Water-Recyclable Chitosan-Based Ion-Imprinted Thermoresponsive Hydrogel for Rare Earth Metal Ions Accumulation

by Yuheng Qiu, Kaiqi Ding, Liwen Tang, Ziyu Qin, Mengting Li and Xueqiong Yin

Int. J. Mol. Sci. 2022, 23(18), 10542; https://doi.org/10.3390/ijms231810542 - 11 Sep 2022

Cited by 3 | Viewed by 2479

Abstract

The demand for rare earth metal increases rapidly in the modern high-tech industry and therefore the accumulation of rare earth metal ions from an aqueous environment becomes a significant concern worldwide. In this paper, a water-recyclable chitosan-based La³⁺-imprinted thermoresponsive hydrogel (CLIT) [...] Read more.

The demand for rare earth metal increases rapidly in the modern high-tech industry and therefore the accumulation of rare earth metal ions from an aqueous environment becomes a significant concern worldwide. In this paper, a water-recyclable chitosan-based La³⁺-imprinted thermoresponsive hydrogel (CLIT) was prepared to accumulate La³⁺ from solution. The CLIT was characterized by DSC, FITR, Raman spectroscopy, XPS, and SEM, which revealed obvious reversible thermosensitivity and imprinted sites of La³⁺ ions. An adsorption capacity of 112.21 mg/g to La³⁺ ions was achieved on CLIT under its optimum adsorption conditions (pH 5, 50 °C, 60 min). The adsorption could be well illustrated by second-order kinetics and Freundlich isotherm models. The La³⁺-adsorbed CLIT could be recycled only by rinsing with 10 °C cold water, with a desorption rate of 96.72%. After ten cycles of adsorption-desorption, CLIT retained good adsorption capability. In the solution containing six ions, the adsorption coefficients k_La3+/Mn+ of CLIT were 2.04–3.51 times that of non-imprinted hydrogel, with k_La3+/Y3+, k_La3+/Gd3+, k_La3+/Al3+, k_La3+/Fe3+ and k_La3+/Cu2+ being 1.67, 2.04, 3.15, 2.72 and 4.84, respectively. Full article

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Graphical abstract
Full article ">Figure 1
Preparation, adsorption and desorption process of CLIT. Full article ">Figure 2
DSC curves of CLIT during repeated tests (the first test (A), second test (B), and third test (C)); FTIR spectra of CS, NIPAM, CLIT, CLIT-La (D); Raman spectra of hydrogels CLIT (25 °C), CLIT (45 °C), CLIT-La (45 °C) (E). Full article ">Figure 3
XPS curves of CLIT and CLIT-La. Full article ">Figure 4
SEM images of CLIT-La ((A) surface; (B) cross section) and CLIT ((C) surface; (D) cross section). Full article ">Figure 5
The effects of temperature (A), adsorption time (B), the pH value of the adsorption solution (C), the initial La3+ concentration (D) on the adsorption capacity of CLIT; (E) The adsorption capacity of CLIT and NIPL to metal ions coexisting in the same solution (containing Al3+, Cu2+, Fe3+, Gd3+, La3+ and Y3+). Full article ">Figure 6
Adsorption simulation of CLIT with (A) quasi-first-order-kinetics; (B) quasi-second-order-kinetics; (C) Freundlich isotherm model; (D) Langmuir isotherm model. Full article ">Figure 7
Effects of (A) eluent temperature, (B) soaking time, (C) repeated desorption times on CLIT desorption and the 10 cycle regeneration performance of CLIT (D). Full article ">

9 pages, 2874 KiB

Open AccessArticle

Interdomain Linker Effect on the Mechanical Stability of Ig Domains in Titin

by Bei Tong, Fang Tian and Peng Zheng

Int. J. Mol. Sci. 2022, 23(17), 9836; https://doi.org/10.3390/ijms23179836 - 30 Aug 2022

Cited by 3 | Viewed by 2421

Abstract

Titin is the largest protein in humans, composed of more than one hundred immunoglobulin (Ig) domains, and plays a critical role in muscle’s passive elasticity. Thus, the molecular design of this giant polyprotein is responsible for its mechanical function. Interestingly, most of these [...] Read more.

Titin is the largest protein in humans, composed of more than one hundred immunoglobulin (Ig) domains, and plays a critical role in muscle’s passive elasticity. Thus, the molecular design of this giant polyprotein is responsible for its mechanical function. Interestingly, most of these Ig domains are connected directly with very few interdomain residues/linker, which suggests such a design is necessary for its mechanical stability. To understand this design, we chose six representative Ig domains in titin and added nine glycine residues (9G) as an artificial interdomain linker between these Ig domains. We measured their mechanical stabilities using atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) and compared them to the natural sequence. The AFM results showed that the linker affected the mechanical stability of Ig domains. The linker mostly reduces its mechanical stability to a moderate extent, but the opposite situation can happen. Thus, this effect is very complex and may depend on each particular domain’s property. Full article

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(a) Schematic architecture of one-half of the sarcomere highlights the polyprotein structure of giant protein titin (colored in purple), not in scale. (b) Structure shows human titin segment I(27–32) chosen for mechanical stability measurements. Except for I27 (PDB:1TIT), all others are simulated structures. (c) The cartoon shows the structure of I30 with a possible disulfide bond between Cys73 and Cys23, while no disulfide is present in other Ig domains. (d) The schematic shows how high-precision AFM-SMFS measures the mechanical stability of Ig domains with an artificial linker. Full article ">Figure 2
(a) Scheme of AFM-SMFS setup to measure the mechanical stability of polyprotein I(27–32). (b) Representative force-extension curves show the unfolding events of Ig domains (marked by a star). The top two curves are from the unfolding of polyprotein with an artificial 9G linker (colored in purple) and the bottom curves are from the natural polyprotein sequence without the linker. The I30 domain shows a peak with ΔLc of 11 nm (in orange), the remaining five Ig domains all show a peak with ΔLc of 28 nm, and GB1 shows a ΔLc of 18 nm. (c,d) Histograms show the unfolding force (c) and ΔLc (d) from the five Ig domains. (e) The histogram shows the ΔLc of I30. Full article ">Figure 3
(a) Scheme of AFM-SMFS setup to measure I(28–30) domains. (b) Representative force-extension curves from polyprotein with linkers (top, colored in blue) and without linker (bottom, black). (c,d) Histograms of their corresponding unfolding force (c) and ΔLc (d) are shown. The star indicates the unfolding event/peak of one protein domain. Full article ">Figure 4
(a) Scheme of AFM-SMFS setup to measure I(30–32) domains. (b) Representative force-extension curves from polyprotein with linkers (top, colored in green) and without linker (bottom, in black). (c,d) Histograms of their corresponding unfolding force (c) and ΔLc (d) are shown. The star indicates the unfolding event/peak. Full article ">Figure 5
(a–c) The scheme (top panel) and mechanical force of I30 in polyprotein I(27–32) (a), I(28–30) (b), and I(30–32) (c). The unfolding force histogram of I30 with the corresponding linker is shown in the middle panel, and the natural sequence without linker is shown at the bottom. The 9G linker was colored red, and the two cysteines forming the disulfide bond were depicted as orange spheres. Full article ">

16 pages, 3309 KiB

Open AccessArticle

Molecular Dynamics Simulation of Coiled Carbon Nanotube Pull-Out from Matrix

by Feng Huang and Shuai Zhou

Int. J. Mol. Sci. 2022, 23(16), 9254; https://doi.org/10.3390/ijms23169254 - 17 Aug 2022

Cited by 6 | Viewed by 2131

Abstract

The interaction between coiled carbon nanotubes (CCNT) and the polymer matrix is important in the mechanical, thermal, and electrical properties of the CCNT reinforced nanocomposite. In this study, molecular dynamics (MD) simulations were performed to study the interfacial characteristics of polymer nanocomposites (PNCs). [...] Read more.

The interaction between coiled carbon nanotubes (CCNT) and the polymer matrix is important in the mechanical, thermal, and electrical properties of the CCNT reinforced nanocomposite. In this study, molecular dynamics (MD) simulations were performed to study the interfacial characteristics of polymer nanocomposites (PNCs). Furthermore, the influence of the geometries of the CCNTs on the load transfer mechanism is evaluated. Pullout simulations considering different geometries of CCNTs are carried out to examine the tensile force and the interfacial shear stress (ISS). The results reveal that the maximal tensile force is reduced by increasing CCNT inner diameters, increasing the helix angles, and decreasing nanotube diameters. The distance between CCNTs and the polymer matrix is varied, and the interfacial distance favors greater ISS. Decreasing the inner diameter of the CCNT, the helix angle, and the tube diameter increases the ISS. The enhancement mechanism of CCNT/polymer composites has also been illustrated. Due to a lack of experimental results, only numerical results are given. The present study helps to understand the interfacial adhesion behavior between the polymer matrix and CCNTs and is expected to contribute to the development of CCNT reinforced polymer composites. Full article

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17 pages, 4625 KiB

Open AccessArticle

An FGFR1-Binding Peptide Modified Liposome for siRNA Delivery in Lung Cancer

by Zhipeng Dong, Yunxue Yin, Jun Luo, Bingxia Li, Fangning Lou, Qiyan Wang, Qingfa Zhou, Baofen Ye and Yue Wang

Int. J. Mol. Sci. 2022, 23(15), 8380; https://doi.org/10.3390/ijms23158380 - 29 Jul 2022

Cited by 6 | Viewed by 2778

Abstract

Liposome modification by targeting ligands has been used to mediate specific interactions and drug delivery to target cells. In this study, a new peptide ligand, CP7, was found to be able to effectively bind to FGFR1 through reverse molecular docking and could cooperate [...] Read more.

Liposome modification by targeting ligands has been used to mediate specific interactions and drug delivery to target cells. In this study, a new peptide ligand, CP7, was found to be able to effectively bind to FGFR1 through reverse molecular docking and could cooperate with VEGFR3 to achieve targeting of A549 cells. CP7 was modified on the surface of the liposome to construct a targeted and safe nanovehicle for the delivery of a therapeutic gene, Mcl-1 siRNA. Due to the specific binding between CP7 and A549 cells, siRNA-loaded liposome-PEG-CP7 showed increased cellular uptake in vitro, resulting in significant apoptosis of tumor cells through silencing of the Mcl-1 gene, which is associated with apoptosis and angiogenesis. This gene delivery system also showed significantly better antitumor activity in tumor-bearing mice in vivo. All of these suggested that siRNA-loaded liposome-PEG-CP7 could be a promising gene drug delivery system with good bioavailability and minimal side effects for treatment. Full article

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Figure 1
(a) Visualization of binding modes within active sites of VEGFR1, VEGFR2, EGFR, and FGFR1. CP7 is shown in stick representation in the binding pocket of selected targets, and proteins are represented using surface model. (b) Interaction between CP7, FGFR1, VEGFR1, and EGFR detected by MST. (c) Level of FGFR1 protein expressed in A549 and HFL-1 cells determined with Western blot technique. (d) Immunofluorescence colocalization of CP-7 peptide with an antibody specific for FGFR1. Scale bar = 50 μm. Full article ">Figure 2
Synthetic route (a), 1H−NMR spectra (b), and FT−IR spectrum (c) of DSPE-PEG and DSPE-PEG-CP7. Full article ">Figure 3
(a) TEM images of liposome-PEG and liposome-PEG-CP7. (b) Size distribution of liposome-PEG and liposome-PEG-CP7 by dynamic light scattering (DLS) analysis. Data are presented as means ± SD (n = 3). (c) siRNA binding ability of liposome-PEG and liposome-PEG-CP7 evaluated by agarose gel retardation assay. (d) Drug release profiles of liposome-PEG-CP7 in PBS at different pH. The right panel is a typical result of drug release assayed by agarose gel electrophoresis. Full article ">Figure 4
(a) Cytotoxic effect of liposome-PEG and liposome-PEG-CP7 on HFL-1 cells. (b) Cytotoxic effect of siMcl-1/liposome-PEG-CP7 on A549 cells. (c) Cell uptake of siRNA/liposomes on A549 cells determined with FCM. (d) Cell uptake and intracellular distribution of siRNA/liposomes in A549 cells determined with CLSM. (e) Apoptosis induction by siRNA/liposomes in A549 cells determined with FCM. (f) Level of Mcl-1 protein expressed in A549 cells treated with siRNA/liposomes determined with Western blot technique. (g) Level of Mcl-1 mRNA expressed in A549 cells treated with siRNA/liposomes determined with RT−PCR. *: differences between siMcl-1/liposome-PEG-CP7 with other groups, ***: p < 0.001, ****: p < 0.0001. Full article ">Figure 5
(a) Photo of tumor tissues from mice treated with PBS, siMcl-1/lipo3000, siMcl-1/liposome-PEG-CP7, siMcl-1/liposome-PEG, NC/liposome-PEG-CP7, and free siMcl-1 at the end of the study. (b) Real-time observation of tumor sizes in vivo after treatment with samples. Error bars represent means ± SD. (c) Real-time weight analysis of mice after each treatment. Error bars represent means ± SD. (d,e) H&E staining of tumor tissue (d) and major organs (heart, liver, spleen, lung, and kidney) (e) after treatment. (f) TUNEL staining of tumor tissue after treatment. Full article ">Scheme 1
Schematic illustration of (a) formation of CP7-modified cationic liposomes and (b) CP7-modified cationic liposomes-mediated efficient siRNA delivery. Full article ">

16 pages, 2914 KiB

Open AccessReview

Antitumor Applications of Photothermal Agents and Photothermal Synergistic Therapies

by Chaowei Li, Yue Cheng, Dawei Li, Qi An, Wei Zhang, Yu Zhang and Yijun Fu

Int. J. Mol. Sci. 2022, 23(14), 7909; https://doi.org/10.3390/ijms23147909 - 18 Jul 2022

Cited by 58 | Viewed by 6343

Abstract

As a new tumor treatment strategy, photothermal therapy (PTT) has the advantages of accuracy, ease of administration, a high efficiency and low side effects. Photothermal transduction agents (PTAs) are the key factor which play an important role in PTT. The mechanism of PTT [...] Read more.

As a new tumor treatment strategy, photothermal therapy (PTT) has the advantages of accuracy, ease of administration, a high efficiency and low side effects. Photothermal transduction agents (PTAs) are the key factor which play an important role in PTT. The mechanism of PTT is discussed in detail. The photothermal conversion efficiency (PCE) can be improved by increasing the light absorption and reducing the light scattering of photothermal conversion agents. Additionally, non-radiative relaxation path attenuation can also promote energy conversion to obtain a higher value in terms of PCE. The structure and photothermal characteristics of various kinds of PTAs (metal materials, carbon-based nanomaterials, two-dimensional nanomaterials, and organic materials) were compared and analyzed. This paper reviews the antitumor applications of photothermal synergistic therapies, including PTT combined with immunotherapy, chemotherapy, and photodynamic therapy. This review proposes that these PTAs promote the development of photothermal synergistic therapies and have a great potential in the application of tumor treatment. Full article

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The Jablonski diagram of different energy transfer mechanisms. Full article ">Figure 2
(A) The xenograft tumor model was established by subcutaneous injection of BGC-823 gastric cancer cells in mice. DOX/SWNT-GEL was injected into the tumor, and then the mice received NIR laser irradiation at the tumor site; (B) DOX release curve of SWNT-GEL in PBS for 28 days at a constant temperature of 43 °C; (C) tumor growth rate of mice treated with different methods and NIR radiation; (D) tumor growth rate of mice with different treatments without NIR radiation. Data was presented as mean ± SD (* indicates p < 0.05 and ** denotes p ≤ 0.01, compared with DOX/SWNT-GEL/NIR or DOX/SWNT-GEL group). Reproduced with permission from ref. [<a href="#B78-ijms-23-07909" class="html-bibr">78</a>] Copyright (2015). Wiley-VCH Verlag. Full article ">Figure 3
MoS2/GO nanocomposites. (A) The overall schematic diagram depicting functionality and biocompatibility enhancement through the synthesizing of MoS2/GO nanocomposites; (B) in vivo biodistribution of various materials in mice. The Mo contents were examined in mice 24 h post i.v. injection. The results from ICP-MS determination were shown as % of injected. In vivo imaging and lung accumulation analysis; (C) ICG fluorescent images of lungs from mice 24 h post-injection of free ICG and ICG-loaded nanomaterials; (D) quantification of relative ICG fluorescence in lungs (n = 3). ICG, indocyanine green. DOX loading capacity and tumor killing efficacy of different materials; (E) DOX loading capacity of nanomaterials (n = 4). * indicates p < 0.05 and # denotes p < 0.001, compared to bulk MoS2-treated group; (F) in vitro tumor killing efficacy of DOX-loaded materials at the same mass concentrations (n = 5). The concentrations of materials were tailored for each type of cells as follows: 2 μg·mL−1 for LLC cells, 6 μg·mL−1 for B16 cells, 30 μg·mL−1 for 4T1 cells, and 15 μg·mL−1 for MDA-MB-231 cells; (G) representative images of metastatic tumor nodules in the lungs from treated and untreated mice with implantation of B16 murine melanoma cancer cells. DOX, doxorubicin; LLC, Lewis lung carcinoma. Reproduced with permission from ref. [<a href="#B89-ijms-23-07909" class="html-bibr">89</a>]. Copyright (2018). Springer Nature. Full article ">Figure 4
(A) Schematic representation of BP@PEG/Ce6 NSs preparation and its application as fluorescence and thermal imaging guided photothermal and photodynamic cancer therapy; (B) fluorescence images of HeLa cells cultured with BP@PEG/Ce6 NSs; (C) intracellular ROS generation of HeLa cells treated with BP@PEG/Ce6 NSs and irradiated with 660 nm laser. Relative viabilities of HeLa cells after being treated with BP@PEG NSs, Ce6, and BP@PEG/Ce6 NSs at different concentrations of BP@PEG NSs (1, 2.5, 5, 10, 25, and 50 ppm) or Ce6 (0.13, 0.325, 0.65, 1.3, 3.25, and 6.5 ppm); (D) without and (E) with irradiation (660 nm, 0.65 W·cm−2, 10 min); (F) fluorescence images of HeLa cells co-stained with Calcein AM (live cells, green) and PI (dead cells, red) upon the addition of BP@PEG NSs, Ce6, and BP@PEG/Ce6 NSs without and with irradiation (660 nm, 0.65 W·cm−2, 10 min). Reproduced with permission from ref. [<a href="#B97-ijms-23-07909" class="html-bibr">97</a>]. Copyright (2018). American Chemical Society. Full article ">Figure 5
IR825 dye as a photothermal conversion agent. (A) Schematic illustration showing the structure and action mechanism of NIR-absorptive DOX-loaded stealth liposome; (B) heating curves of the hydration solution (5% dextrose) and the NSL solution upon continuous NIR laser illumination at a laser power density of 0.5 W·cm−2; (C) DOX release profiles of DOX-loaded NSL at physiological temperature and under NIR light irradiation (power density: 0.5 W·cm−2), respectively. Relative viabilities of HeLa cells incubated with (D) nonloaded NSL and (E) DOX-loaded NSL at various concentrations without and with NIR laser illumination for 5 and 10 min, respectively; (F) confocal laser fluorescence spectroscopy images of live HeLa cells incubated with free DOX (3 μg·mL−1) or DOX-loaded NSL (200 μg·mL−1) solutions. The cell nuclei were stained with H33258. Scale bar is 10 μm. Reproduced with permission from ref. [<a href="#B106-ijms-23-07909" class="html-bibr">106</a>] Copyright (2015). Wiley-VCH Verlag. Full article ">Figure 6
Schematic illustration of chemo-photothermal therapy using reduced graphene oxide/carbon/mesoporous silica nanocookies under NIR light-control. Reproduced with permission from ref. [<a href="#B118-ijms-23-07909" class="html-bibr">118</a>] Copyright (2014). Wiley-VCH Verlag. Full article ">

13 pages, 2795 KiB

Open AccessArticle

Superhydrophobic Paper-Based Microfluidic Field-Effect Transistor Biosensor Functionalized with Semiconducting Single-Walled Carbon Nanotube and DNAzyme for Hypocalcemia Diagnosis

by Hui Wang, Ruipeng Chen, Fan Zhang, Zhixue Yu, Yue Wang, Zhonglin Tang, Liang Yang, Xiangfang Tang and Benhai Xiong

Int. J. Mol. Sci. 2022, 23(14), 7799; https://doi.org/10.3390/ijms23147799 - 15 Jul 2022

Cited by 10 | Viewed by 2639

Abstract

Hypocalcemia is caused by a sharp decline in blood calcium concentration after dairy cow calving, which can lead to various diseases or even death. It is necessary to develop an inexpensive, easy-to-operate, reliable sensor to diagnose hypocalcemia. The cellulose-paper-based microfluidic field-effect biosensor is [...] Read more.

Hypocalcemia is caused by a sharp decline in blood calcium concentration after dairy cow calving, which can lead to various diseases or even death. It is necessary to develop an inexpensive, easy-to-operate, reliable sensor to diagnose hypocalcemia. The cellulose-paper-based microfluidic field-effect biosensor is promising for point-of-care, but it has poor mechanical strength and a short service life after exposure to an aqueous solution. Octadecyltrichlorosilane (OTS), as a popular organosilane derivative, can improve the hydrophobicity of cellulose paper to overcome the shortage of cellulose paper. In this work, OTS was used to produce the superhydrophobic cellulose paper that enhances the mechanical strength and short service life of MFB, and a microfluidic field-effect biosensor (MFB) with semiconducting single-walled carbon nanotubes (SWNTs) and DNAzyme was then developed for the Ca²⁺ determination. Pyrene carboxylic acid (PCA) attached to SWNTs through a non-covalent π-π stacking interaction provided a carboxyl group that can bond with an amino group of DNAzyme. Two DNAzymes with different sensitivities were designed by changing the sequence length and cleavage site, which were functionalized with SPFET/SWNTs-PCA to form Dual-MFB, decreasing the interference of impurities in cow blood. After optimizing the detecting parameters, Dual-MFB could determine the Ca²⁺ concentration in the range of 25 μM to 5 mM, with a detection limit of 10.7 μM. The proposed Dual-MFB was applied to measure Ca²⁺ concentration in cow blood, which provided a new method to diagnose hypocalcemia after dairy cow calving. Full article

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Graphical abstract

Graphical abstract
Full article ">Figure 1
(A) SEM images of (a) CP, (b) SP,(c) SP/SWNTs-PCA, and (d) SP/silver paste; (B) WCA, (C) FTIR, and (D) Raman of CP functionalized with OTS, SWNTs-PCA, EDC-NHS, and DNAzyme; (E) resistances of SPFET modified with different materials (PCA, EDC-NHS, ND-substrate, EA, Tween 20, and CD-EtNa-C5T) at −0.1 V; each data point was an average of measurements from 3 independent biosensors. Full article ">Figure 2
(A) CP-functionalized superhydrophobic solution with incubation time in the range of 2 min to 30 min.; (B) resistance change in SPFET/SWNTs-PCA with different volume of semiconducting ink at VDS = −0.1 V, VG = 0 V; (C) relative resistances changing with the structure and length of DNAzyme for three different Ca2+ concentrations. Each data point is an average of measurements from 3 independent biosensors. Full article ">Figure 3
(A) Relative resistance of SPFET/SWNTs-PCA/DNAzyme and SPFET/SWNTs-PCA/Nonzyme for different Ca2+ concentrations in the range of 25 μM to 100 mM; (B) the linear relationship of the relative resistance and the logarithm of the Ca2+ concentration. Full article ">Figure 4
Preparing process of Dual-MFB structure using superhydrophobic cellulose paper, UV lithography, and screen-printing technology. Full article ">Figure 5
SPFET functionalized with different chemical and biological materials successively (SWNTs-PCA, EDC, NHS, ND/NO-substrate, EA, Tween20, and CD-EtNa-C5T). Full article ">

13 pages, 6767 KiB

Open AccessArticle

Solvent-Free Preparation of Tannic Acid Carbon Dots for Selective Detection of Ni²⁺ in the Environment

by Yan Li, Can Liu, Menglin Chen, Yulong An, Yunwu Zheng, Hao Tian, Rui Shi, Xiahong He and Xu Lin

Int. J. Mol. Sci. 2022, 23(12), 6681; https://doi.org/10.3390/ijms23126681 - 15 Jun 2022

Cited by 16 | Viewed by 3527

Abstract

Carbon dots (CDs) are widely used nanomaterials that not only exhibit good biocompatibility and photostability, but also benefit from a simple preparation process and easy functionalization, making them promising for broad applications in the fields of heavy metal ion detection and optoelectronic devices. [...] Read more.

Carbon dots (CDs) are widely used nanomaterials that not only exhibit good biocompatibility and photostability, but also benefit from a simple preparation process and easy functionalization, making them promising for broad applications in the fields of heavy metal ion detection and optoelectronic devices. Based on the excellent optical properties of CDs and the current situation of increasing energy shortages, this paper selects the natural polyphenolic compound tannic acid (TA) found in biomass materials as the carbon source and innovatively adopts a simple and convenient solvent-free pyrolysis method without auxiliary reagents or solvents. The CDs with good water solubility and certain fluorescence properties were directly prepared under the condition of high temperature, and the obtained CDs exhibited blue fluorescence, and a high QY of 35.4% was obtained at 300 °C. The analysis and results demonstrate the selectivity of these CDs for the detection of various metal ion solutions. In particular, these CDs are sensitive to Ni²⁺ and can be used as fluorescent sensors for the efficient and sustainable detection of Ni²⁺, whereas previous sensors were often specific to Fe³⁺ and Hg²⁺. Thus, a new sensing technique has been developed for the detection of Ni²⁺ to achieve more sensitive and rapid detection. Full article

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Figure 1
The synthesis route of TA-based CDs by solvent-free pyrolysis and basic preparation flow chart. Full article ">Figure 2
(a) TG/DTG curve of tannic acid. (b–d) The evolution of gaseous products for the components at 10 °C min−1. Full article ">Figure 3
(a) UV/vis absorption spectra of CDs based on TA in ethanol solution. (b) PL emission spectra and PL excitation of CDs-Hydro in ethanol solution. (c–f) PL emission spectra and PL excitation of CDs-250 to CDs-400 in ethanol solution. Full article ">Figure 4
Dotted line plot of CDs quantum yield versus reaction temperature. Full article ">Figure 5
(a–e) TEM images of CDs-Hydro, CDs-250 to CDs-400, inset: histograms and Gaussian fittings of particle size distribution. (f–j) HR-TEM images of CDs-Hydro, CDs-250 to CDs-400. Full article ">Figure 6
(a) XPS survey spectra, and (b) high-resolution C1s spectra of CDs-Hydro and CDs-250-400. Full article ">Figure 7
(a–e) PL emission spectra of CDs-Hydro, CDs-250-400 at different durations under visible light in ethanol solution. (f–j) PL emission spectra of CDs-Hydro, CDs-250-400 at different durations under ultraviolet light in ethanol solution. (k–o) PL emission spectra of CDs-Hydro, CDs-250-400 in a water bath at different temperatures in ethanol solution. Full article ">Figure 8
Decay curve of PL intensity of CDs-Hydro, CDs-250-400 with increasing (a) visible and (b) UV irradiation time. (c) Decay curve of PL intensity of CDs-Hydro, CDs-250-400 with increasing temperature. Full article ">Figure 9
Schematic diagram of the mechanism of TA-based CDs synthesized by solvent-free pyrolysis for the detection of Ni2+. Full article ">Figure 10
(a,b) Selectivity of CDs-Hydro and CDs-300 to different metal ions, F0 and F present the fluorescence intensity of CDs before and after adding metal ions. (c,d) Fluorescence emission spectra of CDs-Hydro and CDs-300 after the addition of different concentrations of Ni2+. (e,f) Linear relationship between fluorescence intensity ratio of CDs-Hydro and CDs-300 solution and Ni2+ concentration at different Ni2+ concentrations. Full article ">

13 pages, 8378 KiB

Open AccessArticle

Antibacterial Vancomycin@ZIF-8 Loaded PVA Nanofiber Membrane for Infected Bone Repair

by Yunbo Zhao, Hongshui Wang, Xianrui Zou, Donghui Wang, Ying Fan, Xiaoyan Zhao, Mingjun Li, Lei Yang and Chunyong Liang

Int. J. Mol. Sci. 2022, 23(10), 5629; https://doi.org/10.3390/ijms23105629 - 18 May 2022

Cited by 22 | Viewed by 4280

Abstract

Bone substitutes with strong antibacterial properties and bone regeneration effects have an inherent potential in the treatment of severe bone tissue infections, such as osteomyelitis. In this study, vancomycin (Van) was loaded into zeolitic imidazolate framework-8 (ZIF-8) to prepare composite particles, which is [...] Read more.

Bone substitutes with strong antibacterial properties and bone regeneration effects have an inherent potential in the treatment of severe bone tissue infections, such as osteomyelitis. In this study, vancomycin (Van) was loaded into zeolitic imidazolate framework-8 (ZIF-8) to prepare composite particles, which is abbreviated as V@Z. As a pH-responsive particle, ZIF-8 can be cleaved in the weak acid environment caused by bacterial infection to realize the effective release of drugs. Then, V@Z was loaded into polyvinyl alcohol (PVA) fiber by electrospinning to prepare PVA/V@Z composite bone filler. The drug-loading rate of V@Z was about 6.735%. The membranes exhibited super hydrophilicity, water absorption and pH-controlled Van release behavior. The properties of anti E. coli and S. aureus were studied under the pH conditions of normal physiological tissues and infected tissues (pH 7.4 and pH 6.5, respectively). It was found that the material had good surface antibacterial adhesion and antibacterial property. The PVA/V@Z membrane had the more prominent bacteria-killing effect compared with the same amount of single antibacterial agent containing membrane such as ZIF-8 or Van loaded PVA, and the antibacterial rate was up to 99%. The electrospun membrane had good biocompatibility and can promote MC3T3-E1 cell spreading on it. Full article

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SEM images and size distributions of (a,b) ZIF-8 and (c,d) V@Z particles; TEM images of (e) ZIF-8 and (f) V@Z particles; (g) Elemental mapping of V@Z particles. Full article ">Figure 2
SEM images and contact angle (the insert figure) (a), TEM images (b), and the diameter distribution (c) of different membranes. Full article ">Figure 3
FTIR (a) and water absorption (b) of different membranes; in vitro releasing profile of Van (c) in PVA/Van and PVA/V@Z membranes. Full article ">Figure 4
SEM images of different membranes after 12 h co-culture with E. coli (a) and S. aureus (b) at pH 6.5 and pH 7.4. Full article ">Figure 5
Representative images of agar plates and corresponding data statistics after 24 h co-culture with different membranes: E. coli (a,b) and S. aureus (c,d) (n = 3). (* p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001). Full article ">Figure 6
CCK-8 results of MC3T3-E1 cells after 24 h co-culture with different membranes (n = 5). (ns, not significant). Full article ">Figure 7
(a) Images of live/dead staining of MC3T3-E1 cells after being co-cultured with different fibrous membrane extracts for 24 h. Calcein–AM (green): live cells. PI (red): dead cells; Merge: merged channel of live/dead cells. (b) Statistical quantification of the cell number, n is the number of confocal pictures analyzed (n = 5). (ns, not significant). Full article ">Figure 8
(a) Images of MC3T3-E1 cells stained with F-actin (red) and nucleus (blue) after being cultured on different fibrous membranes for 72 h: TRITC phalloidin: F-actin; DAPI: nuclei; Merge: merged channel of F-actin and DAPI; (b) Corresponding statistical results of cell spreading area. Mean values and standard deviations of 50 cells are presented. (**** p < 0.0001). Full article ">Scheme 1
The preparation routes and biological applications of PVA/V@Z membrane. Full article ">

15 pages, 3462 KiB

Open AccessArticle

Exploring the Effects of the Interaction of Carbon and MoS₂ Catalyst on CO₂ Hydrogenation to Methanol

by Pingping Cui, Ruyu Sun, Linfei Xiao and Wei Wu

Int. J. Mol. Sci. 2022, 23(9), 5220; https://doi.org/10.3390/ijms23095220 - 7 May 2022

Cited by 13 | Viewed by 2911

Abstract

Hydrogenation of CO₂ to form methanol utilizing green hydrogen is a promising route to realizing carbon neutrality. However, the development of catalyst with high activity and selectivity to methanol from the CO₂ hydrogenation is still a challenge due to the chemical [...] Read more.

Hydrogenation of CO₂ to form methanol utilizing green hydrogen is a promising route to realizing carbon neutrality. However, the development of catalyst with high activity and selectivity to methanol from the CO₂ hydrogenation is still a challenge due to the chemical inertness of CO₂ and its characteristics of multi-path conversion. Herein, a series of highly active carbon-confining molybdenum sulfide (MoS₂@C) catalysts were prepared by the in-situ pyrolysis method. In comparison with the bulk MoS₂ and MoS₂/C, the stronger interaction between MoS₂ and the carbon layer was clearly generated. Under the optimized reaction conditions, MoS₂@C showed better catalytic performance and long-term stability. The MoS₂@C catalyst could sustain around 32.4% conversion of CO₂ with 94.8% selectivity of MeOH for at least 150 h. Full article

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12 pages, 2783 KiB

Open AccessArticle

Reducing Endogenous Labile Zn May Help to Reduce Smooth Muscle Cell Injury around Vascular Stents

by Zheng Zeng, Yinhong Xie, Li Li, Huanran Wang, Jianying Tan, Xia Li, Qihao Bian, Yu Zhang, Tao Liu, Yajun Weng and Junying Chen

Int. J. Mol. Sci. 2022, 23(9), 5139; https://doi.org/10.3390/ijms23095139 - 5 May 2022

Cited by 3 | Viewed by 2365

Abstract

Vascular stent service involves complex service environments and performance requirements, among which the histocompatibility of the stent could seriously affect the therapeutic effect. In the pathology of vascular disease, the thin fiber cap is easily ruptured, exposing the necrotic core below, and triggering [...] Read more.

Vascular stent service involves complex service environments and performance requirements, among which the histocompatibility of the stent could seriously affect the therapeutic effect. In the pathology of vascular disease, the thin fiber cap is easily ruptured, exposing the necrotic core below, and triggering a series of dangerous biochemical reactions. In contrast, the thin neointima, considered an essential structure growing on the stent, may evolve into vulnerable plaque structures due to lesions induced by the stent. Therefore, the reduction of necrosis around the stent below the thin neointima is indispensable. In this work, different cell model experiments suggested that the content of endogenous labile Zn positively correlated with cell injury. Zinquin-Zn fluorescence experiments and zinc ion channels research suggested that the change in the content of endogenous labile Zn in smooth muscle cells is affected by different stent coatings. The content of endogenous labile Zn in cells negatively correlated with cell viability. Animal experiments indirectly verified the increase in endogenous labile Zn by detecting the expression of Zn regulatory protein (metallothionein) in the necrotic tissues. Reducing the content of endogenous labile Zn may favor a reduction in smooth muscle cell injury and necrosis. This biochemical mechanism is effective in improving the therapeutic effect of vascular stents. Full article

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Figure 1
Schematic illustration showing the potential relationship between endogenous labile Zn and cell injury and its potential application in stents (SMCs, smooth muscle cells). Full article ">Figure 2
Zinquin-Zn fluorescence and the mean fluorescence intensity (MFI) of Zinquin-Zn in different cell injury models, including a normal group, oxidative injury group, and apoptosis group. Zinquin-Zn fluorescence for SMC (a), ECs (c) and MSCs (e) in different cell models. The MFI of Zinquin-Zn for SMC (b), ECs (d) and MSCs (f). (g) Cell injury accompanied by an increase in endogenous labile Zn (SMCs, smooth muscle cells; ECs, endothelial cells; MSCs, mesenchymal stem cells; data were analyzed using 1-way ANOVA, *** p < 0.001; ns, not significant). Full article ">Figure 3
(a) Schematic illustration of the preparation of HPLL and HPLLZn. (b) AFM images of DA, HPLL, and HPLLZn. (c) The EPR spectra of HPLLZn particles used for coating preparation. (d) Zn 2p XPS spectrum of coatings. (e) Quantitative characterization of Zn leaching from HPLLZn (DA, dopamine coating; HPLL, heparin/poly-L-lysine coating; HPLLZn, heparin/poly-L-lysine/Zn coating). Full article ">Figure 4
(a) Zinquin-Zn fluorescence in smooth muscle cells after contact with different coatings. (b) Semi-quantitative statistics of the mean fluorescence intensity (MFI) of Zinquin. The relative transcription level of mRNA is related to the Zn ion channel, (c) ZnT1 for efflux of the Zn ion, and (d) ZIP1 mRNA for the influx. (e) The average relative ratio of the zinc channel mRNA transcription levels. (f) Schematics of the sources of the fluorescent. (g) Rhodamine 123 fluorescence images of SMCs’ growth and (h) the cell viability after incubation for 1 day and 3 days (TCP, tissue culture plate; data were analyzed using 1-way ANOVA, * p < 0.05, ** p < 0.01, *** p < 0.001; ns, not significant). Full article ">Figure 5
(a) Schematics of stainless-steel wires with different coatings implanted into Sprague Dawley rats’ abdominal aorta. (b) Hematoxylin and eosin staining and (b-i) quantification of the necrotic area surrounding the different coatings (the white dotted line shows the necrotic area). (c) Immunohistochemical of metallothionein protein expression and (c-i) semiquantitative analysis of the area (red marks regions with high MT expression). (d) The expression edge of α-SMA (green) and (d-i) quantification of the area without αSMA in the tissue close to the coating after a 1-month implantation (the white dotted line shows the edge closest to the coating). (e) Immunofluorescence staining of CD31 and (e-i) the endothelialization integrity. (f) Schematics of vascular stents with different coatings implanted in New Zealand white rabbits’ iliac artery. (g) Histomorphometric analysis of stents after a 1-month implantation and (g-i) quantification of the mean neointimal thickness. (h) The potential mechanism of this rule applies to the cardiovascular stent. (HE, hematoxylin and eosin stain; MT, metallothionein; α-SMA, α-smooth muscle actin; CD31, cluster of differentiation 31; DAPI, 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride; data were analyzed using 1-way ANOVA, * p < 0.05, *** p < 0.001; ns, not significant). Full article ">

11 pages, 2327 KiB

Open AccessArticle

Photodynamic Therapy of Up-Conversion Nanomaterial Doped with Gold Nanoparticles

by Wei Zhang, Yang Zang, Yanli Lu, Jinghui Han, Qingyun Xiong and Jinping Xiong

Int. J. Mol. Sci. 2022, 23(8), 4279; https://doi.org/10.3390/ijms23084279 - 13 Apr 2022

Cited by 7 | Viewed by 2184

Abstract

Two key concerns exist in contemporary cancer chemotherapy: limited therapeutic efficiency and substantial side effects in patients. In recent years, researchers have been investigating the revolutionary cancer treatment techniques of photodynamic therapy (PDT) and photothermal therapy (PTT) proposed by many scholars. A photothermal [...] Read more.

Two key concerns exist in contemporary cancer chemotherapy: limited therapeutic efficiency and substantial side effects in patients. In recent years, researchers have been investigating the revolutionary cancer treatment techniques of photodynamic therapy (PDT) and photothermal therapy (PTT) proposed by many scholars. A photothermal treatment of cancer was synthesized using the hydrothermal method which has high photothermal conversion efficiency and can generate reactive oxygen species (ROS) in cells. Photothermal treatment of tumors has a good short-term effect and photodynamic therapy lasts longer. However, both PTT and PDT have their inevitable shortcomings and it is difficult to completely eradicate a tumor using a single mode of treatment. PTT and PDT synergistic treatment not only inherits the advantages of low toxicity and side effects of phototherapy but also enables the two treatment methods to complement each other. It is an effective strategy to improve curative effects and reduce toxic and side effects. Furthermore, gold doped UCNPs have an exceptionally high target recognition for tumor cells. The gold doped UCNPs, in particular, are non-toxic to normal tissues, endowing the as-prepared medications with outstanding therapeutic efficacy and exceptionally low side effects. These findings may encourage the creation of fresh, effective imaging-guided approaches to meet the goal of photothermal cancer therapy. Full article

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19 pages, 5701 KiB

Open AccessArticle

Microfluidic-Based Cationic Cholesterol Lipid siRNA Delivery Nanosystem: Highly Efficient In Vitro Gene Silencing and the Intracellular Behavior

by Zhaoyuan Zhu, Li Zhang, Ruilong Sheng and Jian Chen

Int. J. Mol. Sci. 2022, 23(7), 3999; https://doi.org/10.3390/ijms23073999 - 3 Apr 2022

Cited by 4 | Viewed by 3489

Abstract

Safe and efficient delivery of small interfering RNA (siRNA) is essential to gene therapy towards intervention of genetic diseases. Herein, we developed a novel cationic cholesterol lipid derivative (CEL) in which cholesterol hydrophobic skeleton was connected to L-lysine cationic headgroup via a hexanediol [...] Read more.

Safe and efficient delivery of small interfering RNA (siRNA) is essential to gene therapy towards intervention of genetic diseases. Herein, we developed a novel cationic cholesterol lipid derivative (CEL) in which cholesterol hydrophobic skeleton was connected to L-lysine cationic headgroup via a hexanediol linker as the non-viral siRNA delivery carrier. Well-organized CEL/siRNA nanocomplexes (100–200 nm) were prepared by microfluidic-assisted assembly of CEL and siRNA at various N/P ratios. The CEL and CEL/siRNA nanocomplexes have lower cytotoxicity compared with bPEI25k. Delightfully, we disclosed that, in Hela–Luc and H1299–Luc cell lines, the micro-fluidic-based CEL/siRNA nanocomplexes exhibited high siRNA transfection efficiency under both serum-free condition (74–98%) and low-serum circumstances (80–87%), higher than that of lipofectamine 2000. These nanocomplexes also showed high cellular uptake through the caveolae/lipid-raft mediated endocytosis pathway, which may greatly contribute to transfection efficiency. Moreover, the time-dependent (0–12 h) dynamic intracellular imaging demonstrated the efficient delivery to cytoplasm after lysosomal co-localization. The results indicated that the microfluidic-based CEL/siRNA nanosystems possessed good stability, low cytotoxicity, high siRNA delivery efficiency, rapid cellular uptake and caveolae/lipid raft-dependent internalization. Additionally, this study provides a simple approach for preparing and applying a “helper lipid-free” cationic lipid siRNA delivery system as potential nanotherapeutics towards gene silencing treatment of (tumor) diseases. Full article

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State-of-the-Art Materials Science in China

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2024

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