CN110591430B

CN110591430B - Near-infrared response antibacterial nano composite coating and preparation method and application thereof

Info

Publication number: CN110591430B
Application number: CN201910766721.6A
Authority: CN
Inventors: 刘想梅; 洪丽; 吴水林
Original assignee: Hubei University
Current assignee: Hubei University
Priority date: 2019-08-20
Filing date: 2019-08-20
Publication date: 2021-05-25
Anticipated expiration: 2039-08-20
Also published as: CN110591430A

Abstract

The invention discloses a near-infrared response antibacterial nano composite coating and a preparation method thereof, wherein a bismuth sulfide nanorod array grows on the surface of a substrate of the coating, silver phosphate nano particles cover the surface of the bismuth sulfide nanorod array, and the preparation method of the composite coating comprises the following steps: s1, substrate pretreatment, S2, synthesis of bismuth sulfide nanorod arrays, and S3, synthesis of silver phosphate loaded bismuth sulfide nanorod arrays. The coating material can quickly and efficiently kill bacteria under 808-nanometer laser irradiation or in dark conditions, has excellent antibacterial performance, and can be used for preparing implanted medical instruments.

Description

Near-infrared response antibacterial nano composite coating and preparation method and application thereof

Technical Field

The invention relates to the technical field of nano composite materials, in particular to a near-infrared response antibacterial nano composite coating and a preparation method and application thereof.

Background

The biomedical metal material is an inert material of a metal or an alloy used as a biomedical material, and is also called a surgical metal material or a medical metal material. The material has high mechanical strength and fatigue resistance, and is the force bearing implant material which is widely applied in clinic. The medical titanium metal and the alloy thereof have the elastic modulus similar to that of natural bones, have excellent corrosion resistance and biocompatibility, and are widely applied to clinic at present.

With the development of modern medical systems and the aging of the population, and car accidents or other accidents, people have an increasing demand for artificial replacement materials for bones. At present, medical titanium alloy is widely applied to orthopedic implantation, but even people carry out comprehensive disinfection and sterilization treatment on surgical instruments, the problem of bacterial infection caused by a small part of medical implants is inevitable, the infection not only brings physical and economic burden to patients, but also leads to amputation and even death of the patients.

Medically, the traditional way of treating bacterial infections is to use oral or injected antibiotics to kill the bacteria, but the antibiotics have a long bactericidal effect, and abuse of antibiotics may cause the bacteria to develop resistance, and in severe cases may lead to the appearance of "superbacteria". Photodynamic or photothermal therapy is used as a novel sterilization means, the problem of long sterilization period of antibiotics is solved, and meanwhile, the generation of bacterial drug resistance is also avoided. Near-infrared light is widely used in light-controlled therapy due to its good tissue penetration and mildness. Therefore, it is necessary to develop a fast and efficient bactericidal coating for near infrared control.

Disclosure of Invention

In view of the above, the present invention provides a near-infrared responsive antibacterial nanocomposite coating, which can kill bacteria under 808 nm laser irradiation or in dark conditions, and is fast, efficient and durable.

In order to achieve the purpose, the invention specifically adopts the following technical scheme:

the invention provides a near-infrared response antibacterial nano composite coating, wherein a bismuth sulfide nanorod array grows on the surface of a substrate of the coating, and silver phosphate nano particles cover the surface of the bismuth sulfide nanorod array. The thickness of the silver phosphate nano particle loaded bismuth sulfide nanorod array is 1-2 mu m, and the particle size of the silver phosphate nano particles is 12-30 nm.

Preferably, the substrate is a titanium sheet.

The invention provides a preparation method of the near-infrared response antibacterial nano composite coating, which comprises the following steps:

s1, substrate pretreatment: polishing the surface of a substrate by using sand paper with different meshes, carrying out alkali heat treatment and drying, and then placing the substrate in an ethanol solution of 4-mercaptobenzoic acid to carry out self-assembly of 4-mercaptobenzoic acid molecules on the surface of the substrate;

s2, synthesis of bismuth sulfide nanorod arrays: dissolving bismuth nitrate in a nitric acid solution to obtain a solution A, dissolving thiourea in deionized water to obtain a solution B, mixing the solution A and the solution B, placing the mixture in a water bath, placing the pretreated substrate in the mixed solution, and carrying out a constant-temperature water bath reaction to obtain a bismuth sulfide nanorod array;

s3, synthesizing a silver phosphate loaded bismuth sulfide nanorod array: and (4) placing the bismuth sulfide nano-array obtained in the step (S2) in a silver nitrate solution for adsorption, then dropwise adding a disodium hydrogen phosphate dodecahydrate solution, and reacting for 0.5h to obtain the silver phosphate loaded bismuth sulfide nano-rod array.

Preferably, the alkali heat treatment of S1 is to put the substrate into a hydrothermal reaction kettle containing 4M KOH solution, and treat the substrate at 80-120 ℃ for 1.5 h.

Preferably, the concentration of the nitric acid solution in S2 is 3M, and the molar ratio of bismuth nitrate to thiourea in the mixed solution is 1: 10-2: 5.

Preferably, in the constant-temperature water bath reaction of S2, the substrate is suspended in the mixed solution with the reaction surface facing downwards, the reaction temperature is 50-60 ℃, and the reaction time is 12-24 hours.

Preferably, the adsorption time of S3 is 0.5-3 h, the concentration ratio of silver nitrate to disodium hydrogen phosphate dodecahydrate is 5: 7-1: 2, and the reaction time is 0.5-6 h.

Preferably, the dropwise addition of the disodium hydrogen phosphate dodecahydrate solution is carried out by the following specific operations: stirred vigorously and added dropwise slowly, and kept protected from light during the reaction.

The third aspect of the invention provides the application of the near-infrared response antibacterial nano composite coating in the preparation of an implanted medical appliance.

The invention has the beneficial effects that:

(1) bismuth sulfide is used as a photocatalytic semiconductor with a narrow band gap, has excellent performance in the aspect of photocatalysis, can generate active oxygen with a sterilization effect under the irradiation of 808-nanometer laser with excellent tissue penetration performance, and can be prepared on the surface of titanium metal to endow the coating with light-operated antibacterial performance.

(2) By further modifying the silver phosphate nano particles, the photocatalytic performance of bismuth sulfide under near-infrared illumination can be improved, and more active oxygen is generated for more efficient light-operated sterilization; meanwhile, the composite coating can release trace silver ions into an environmental solution, so that the coating has a good sterilization effect under a dark condition.

(3) The bismuth sulfide nanorod is formed on the surface of the substrate through simple water bath heating, and the silver phosphate nano particles are loaded on the surface of the bismuth sulfide nanorod through an electrostatic adsorption strategy.

(4) The surface of the inert metal titanium is subjected to alkali heating and grafted with 4-mercaptobenzoic acid to provide nucleation sites for growing bismuth sulfide, so that the growth of a bismuth sulfide nanorod array on the surface of a titanium sheet becomes possible.

Drawings

FIG. 1 is an SEM image of an array of bismuth sulfide nanorods prepared on the surface of a titanium sheet in example 1;

FIG. 2 is an SEM image of a silver phosphate loaded bismuth sulfide nanorod array prepared on the surface of a titanium plate in example 1;

FIG. 3 is a SEM sectional view of a silver phosphate loaded bismuth sulfide nanorod array prepared on the surface of a titanium plate in example 1;

FIG. 4 is an XPS plot of the coating in example 1.

FIG. 5 is a graph of the photocatalytic degradation of DCFH dye of the coating of example 1;

FIG. 6 is a statistical chart of the antibacterial rate of the coating of example 1 under 808 nm illumination for 15 min; (a is Staphylococcus aureus, b is Escherichia coli);

FIG. 7 is a statistical graph of the antibacterial efficiency of the coating against Staphylococcus aureus and Escherichia coli after co-culturing the coating with bacteria in example 1 for one day in dark conditions;

FIG. 8 is an SEM image of a silver phosphate-loaded bismuth sulfide nanorod array prepared on the surface of a titanium plate in example 2;

FIG. 9 is an SEM image of bismuth sulfide prepared on the surface of a titanium plate in example 3;

FIG. 10 is an SEM image of bismuth sulfide prepared on the surface of a titanium plate in example 4;

FIG. 11 is SEM images of bismuth sulfide prepared on the surface of a titanium sheet under different water bath times;

FIG. 12 is an SEM image of bismuth sulfide prepared on the surface of a titanium plate in example 5;

FIG. 13 is an SEM image of bismuth sulfide prepared on the surface of the titanium plate in comparative example 1;

FIG. 14 is an SEM image of bismuth sulfide prepared on the surface of the titanium plate in comparative example 2.

Detailed Description

In order that the invention may be better understood, it is further illustrated by the following detailed description, but is not to be construed as being limited thereto.

Example 1:

a near-infrared response antibacterial nano composite coating is prepared by the following steps:

(1) polishing a titanium metal wafer with the diameter of 6mm and the thickness of 2mm by using SiC sand paper with the specification of No. 240, No. 400, No. 600, No. 800 and No. 1200 respectively until the surface is smooth, then sequentially putting acetone, ethanol and deionized water into the silicon carbide wafer for ultrasonic cleaning for 15min, removing impurities on the surface of the titanium wafer, and drying the silicon carbide wafer at 37 ℃ in a vacuum environment for later use.

(2) The cleaned and dried titanium sheet is put into a 100mL hydrothermal reaction kettle, 75mL of 4M KOH solution is poured into the reaction kettle, the reaction kettle is sealed, and the titanium sheet is heated in an oven to 80 ℃ and then kept for 1.5 h. And naturally cooling to room temperature after the reaction is finished, opening the reaction kettle, taking out the titanium sheet subjected to alkali heat treatment, sequentially washing the titanium sheet by using ethanol and water, and drying the titanium sheet at 37 ℃ in a vacuum environment for later use.

(3) Placing the titanium sheet subjected to alkali heat treatment and drying in a 100mL beaker with the alkali heat side facing upwards, adding 20mL of 10mM 4-mercaptobenzoic acid solution to enable the solution to submerge the surface of the titanium sheet, sealing the beaker, and placing the sealed beaker in a 37 ℃ oven to enable 4-mercaptobenzoic acid molecules to self-assemble on the surface of the titanium sheet to provide nucleation sites for bismuth sulfide growth. After the reaction is finished, taking out the titanium sheet, washing the titanium sheet by using ethanol, and drying the titanium sheet at 37 ℃ in a vacuum environment for later use.

(4) And (3) gluing the self-assembled titanium sheet on a flat plate capable of floating in the solution by using silicon glue, exposing the modified surface of the titanium sheet subjected to the steps to the outside, and standing at room temperature for 6 hours to dry the silicon gel for later use.

(5) 1mmol of bismuth nitrate was dissolved in 10mL of 3M nitric acid solution, 10mmol of thiourea was dissolved in 100mL of deionized water, and the two were mixed and placed in a 150mL beaker and heated to 50 ℃ in a water bath.

(6) And (3) placing the flat plate in the step (4) in the mixed reaction solution, immersing the surface adhered with the titanium sheet in the solution, and sealing the container to react in a constant-temperature water bath at 50 ℃ for 24 hours. And taking out the titanium sheet, washing the titanium sheet with ethanol and deionized water, and drying the titanium sheet in a vacuum environment at 37 ℃ to obtain the bismuth sulfide nanorod array growing on the surface of the titanium sheet for later use.

(7) And placing the obtained bismuth sulfide nano array in a 20mL beaker, adding the bismuth sulfide nano array into 10mL of 1mg/mL silver nitrate solution in a dark place, and carrying out electrostatic adsorption on silver ions for 1 h.

(8) Under vigorous stirring, 2mL of 7mg/mL disodium hydrogen phosphate dodecahydrate solution is slowly added dropwise into the silver nitrate solution, and the reaction is carried out for 0.5h, and the reaction process is kept in the dark. And after the reaction is finished, taking out the titanium sheet, washing the titanium sheet by using ethanol and deionized water, and drying the titanium sheet in a dark place at 37 ℃ in a vacuum environment to obtain the silver phosphate loaded bismuth sulfide nanorod array, wherein the sample is stored in the dark place.

Scanning electron microscopy and element detection are carried out on the sample prepared by the method, and the result shows that bismuth sulfide in the titanium sheet in the figure 1 is in a uniform rod-like structure on the surface, and the surface is smooth and has no other impurities; after loading the silver phosphate nanoparticles, as shown in fig. 2, the coating still maintains the rod-like morphology, but the smooth bismuth sulfide surface is covered by the dense silver phosphate nanoparticles, and the particle size of the silver phosphate is about 25 nm; the cross-sectional view of fig. 3 shows that the thickness of the composite coating is about 1.5 microns. The XPS results of fig. 4 show that the silver phosphate loaded samples have peaks for Bi 4f, S2P, Ag 3d, P2P and O1S, indicating successful preparation of the samples.

The sample prepared by the method is characterized by photocatalytic performance and bactericidal effect: 1) as shown in fig. 5, the detection result of the DCFH fluorescent dye shows that the coating of the silver phosphate-loaded bismuth sulfide nanorod array has the most degradation condition on the DCFH dye under 808 nm illumination, and shows the strongest photocatalytic activity, which indicates that the amount of active oxygen generated by the coating is the most; 2) FIGS. 6a and b are statistical graphs of the antibacterial rate of the sample for 15min under 808 nm illumination to Staphylococcus aureus and Escherichia coli, respectively. The coating of the silver phosphate loaded bismuth sulfide nanorod array shows the highest antibacterial effect, the antibacterial effect reaches more than 99%, and the composite coating achieves the effects of quick and efficient sterilization; 3) FIG. 7 is a statistical graph of the antimicrobial efficiency of the coating against Staphylococcus aureus and Escherichia coli after co-culturing the samples with bacteria for one day in the dark. It can be seen that the sample also has good bactericidal effect on two kinds of bacteria under dark conditions, which indicates that the coating has long-term bactericidal effect.

Example 2

the steps (1), (2), (3), (4), (5), (6) and (7) are the same as those in example 1.

(8) 2mL of 7mg/mL disodium hydrogen phosphate dodecahydrate solution is quickly added without stirring, and the reaction is fully performed for 0.5h, and the reaction process is kept in the dark. And after the reaction is finished, taking out the titanium sheet, washing the titanium sheet by using ethanol and deionized water, and drying the titanium sheet in a dark place at 37 ℃ in a vacuum environment to obtain the silver phosphate loaded bismuth sulfide nanorod array, wherein the sample is stored in the dark place.

The sample prepared by the method is detected by a scanning electron microscope, and the result is shown in fig. 8, the bismuth sulfide nano-rods are not completely loaded with the silver phosphate nano-particles, and the sample synthesis is not uniform enough. It is shown that the speed of adding the disodium hydrogen phosphate dodecahydrate solution into the silver nitrate solution can affect the uniformity of the sample, and the excessively high dropping speed can cause the non-uniform synthesis of the sample.

Example 3

the steps (1), (3), (4), (5), (6), (7) and (8) are the same as those in example 1;

(2) the cleaned and dried titanium sheet is put into a 100mL hydrothermal reaction kettle, 75mL of 4M KOH solution is poured into the reaction kettle, the reaction kettle is sealed, and the titanium sheet is heated in an oven to 120 ℃ and then kept for 1.5 h. And naturally cooling to room temperature after the reaction is finished, opening the reaction kettle, taking out the titanium sheet subjected to alkali heat treatment, sequentially washing the titanium sheet by using ethanol and water, and drying the titanium sheet at 37 ℃ in a vacuum environment for later use.

And (3) performing scanning electron microscope detection on the sample obtained in the step (6), wherein the result is shown in fig. 9, the bismuth sulfide is in a sheet-like rod-like structure, and the particle size of the alkali-heat titanium sheet at 120 ℃ is much larger than that of the bismuth sulfide grown on the alkali-heat titanium sheet at 80 ℃. This is because the network structure is different after alkali heating at different temperatures, which causes the appearance of the bismuth sulfide growth to be inconsistent. Therefore, the bismuth sulfide with different morphologies can be regulated and controlled to grow by controlling the alkali-thermal process of the titanium sheet.

Example 4

the steps (1), (2), (3), (4) and (5) are the same as those in example 1;

(6) and (3) placing the flat plate in the step (4) in the mixed reaction solution, immersing the surface adhered with the titanium sheet into the solution, and sealing the container to react in a constant-temperature water bath at 60 ℃ for 12 hours. And taking out the titanium sheet, washing the titanium sheet with ethanol and deionized water, and drying the titanium sheet in a vacuum environment at 37 ℃ to obtain the bismuth sulfide nanorod array growing on the surface of the titanium sheet for later use.

(7) And placing the obtained bismuth sulfide nano array in a 20mL beaker, adding the bismuth sulfide nano array into 10mL of 1mg/mL silver nitrate solution in a dark place, and carrying out electrostatic adsorption on silver ions for 0.5 h.

(8) Under vigorous stirring, 3mL of 7mg/mL disodium hydrogen phosphate dodecahydrate solution is slowly and dropwise added into the silver nitrate solution, and the reaction is carried out for 6 hours, and the reaction process is kept in the dark. And after the reaction is finished, taking out the titanium sheet, washing the titanium sheet by using ethanol and deionized water, and drying the titanium sheet in a dark place at 37 ℃ in a vacuum environment to obtain the silver phosphate loaded bismuth sulfide nanorod array, wherein the sample is stored in the dark place.

The prepared composite coating sample still shows good photocatalytic performance and sterilization effect, and the effect is inferior to that of example 1. And (4) carrying out scanning electron microscope detection on the sample obtained in the step (6), wherein the result is shown in fig. 10, and the reticular titanium substrate subjected to alkali heating is basically covered by the bismuth sulfide nano-rods, but shows the porous appearance of the titanium sheet.

Experiments prove that under the same conditions, the time of the constant-temperature water bath reaction in the step (6) influences the coverage rate of the bismuth sulfide nanorods on the titanium sheet, when the reaction time is 4 hours, as shown in (a) in fig. 11, the titanium substrate shows a net structure after alkali heating, and a small amount of bismuth sulfide is distributed on the surface of the titanium substrate; when the reaction time is 30h, as shown in fig. 11 (b), the titanium substrate after the alkali heating is completely covered by the bismuth sulfide nanorods, and a part of the bismuth sulfide nanorods protrude on the surface of the coating due to insufficient growth space and show flower-like morphology. Too much and too little bismuth sulfide nano-rods are not beneficial to the antibacterial performance of the composite coating.

Example 5

the steps (1), (2), (3), (4), (6), (7) and (8) are the same as those in example 1.

(5) 2mmol of bismuth nitrate was dissolved in 10mL of 3M nitric acid solution and 5mmol of thiourea was dissolved in 100mL of deionized water, and the two were mixed and placed in a 150mL beaker and heated to 50 ℃ in a water bath.

The prepared composite coating sample still shows good photocatalytic performance and sterilization effect, and the effect is inferior to that of example 1. And (3) performing scanning electron microscope detection on the sample obtained in the step (6), wherein the result is shown in fig. 12, bismuth sulfide still keeps a rod-shaped structure, the width of a rod is in a micron level, but the structure is more irregular, and the bismuth sulfide is sparsely distributed on the surface of a titanium substrate.

Comparative example 1

The steps (1) (4) (5) (6) of example 1 were followed in this order to obtain bismuth sulfide coatings grown on titanium substrates without alkali heat treatment and immersion of 4-MBA molecules.

Scanning electron microscope detection is carried out on the sample prepared by the method, and the result is shown in fig. 13, wherein a very small amount of bismuth sulfide grows on the surface of titanium, which indicates that the bismuth sulfide nanorod coating cannot grow in 24 hours on the titanium sheet without alkali heat treatment and grafted with 4-MBA molecules.

Comparative example 2

The procedure of (1), (3), (4), (5) and (6) of example 1 was followed in order to obtain a bismuth sulfide nanorod array grown on a titanium substrate without being subjected to alkaline heat treatment and then being soaked in 4-MBA molecules.

The sample prepared by the method is detected by a scanning electron microscope, and the result is shown in fig. 14, wherein the width of the bismuth sulfide is micron-sized and the bismuth sulfide is irregularly arranged on the surface of the titanium sheet. The titanium plate without alkali heat treatment has poor activity, only a small amount of 4-MBA molecules can be grafted, and a uniform and compact nanorod array cannot be formed on the surface of the titanium plate.

The above is, of course, only a specific application example of the present invention, and the scope of the present invention is not limited in any way. In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by using equivalent substitutions or equivalent transformations fall within the scope of the present invention.

Claims

1. The near-infrared response antibacterial nano composite coating is characterized in that a bismuth sulfide nanorod array grows on the surface of a substrate of the coating, and silver phosphate nano particles cover the surface of the bismuth sulfide nanorod array;

the coating is prepared by the following steps:

s3, synthesizing a silver phosphate loaded bismuth sulfide nanorod array: and (4) placing the bismuth sulfide nano-array obtained in the step (S2) in a silver nitrate solution for adsorption, and then dropwise adding a disodium hydrogen phosphate dodecahydrate solution for reaction to obtain the silver phosphate loaded bismuth sulfide nano-rod array.

2. The near-infrared-responsive antimicrobial nanocomposite coating according to claim 1, wherein the substrate is a titanium sheet.

3. The method for preparing the near-infrared-responsive antibacterial nanocomposite coating according to any one of claims 1 to 2, characterized by comprising the following steps:

4. The method of claim 3, wherein the near-infrared-responsive antibacterial nanocomposite coating is prepared by the following steps,

s1 the alkali heat treatment is specifically that the substrate is put into a hydrothermal reaction kettle filled with 4M KOH solution and treated for 1.5h at 80-120 ℃.

5. The preparation method of the near-infrared response antibacterial nano composite coating according to claim 3, characterized in that the concentration of the nitric acid solution S2 is 3M, and the molar ratio of bismuth nitrate to thiourea in the mixed solution is 1: 10-2: 5.

6. The method for preparing a near-infrared-responsive antibacterial nano-composite coating according to claim 3, wherein in the constant-temperature water bath reaction of S2, a substrate is suspended in the mixed solution, the reaction temperature is 50-60 ℃, and the reaction time is 12-24 hours.

7. The preparation method of the near-infrared-response antibacterial nano composite coating according to claim 3, wherein the adsorption time of S3 is 0.5-3 h, the concentration ratio of silver nitrate to disodium hydrogen phosphate dodecahydrate is 5: 7-1: 2, and the reaction time is 0.5-6 h.

8. The method of claim 3, wherein the dropping of the disodium hydrogen phosphate dodecahydrate solution in S3 is specifically performed by: stirred vigorously and added dropwise slowly, and kept protected from light during the reaction.

9. Use of the near-infrared-responsive antibacterial nanocomposite coating according to any one of claims 1 to 2 for the preparation of an implantable medical device.