A preparation method of a porous polyethyleneimine-silver nanocluster / chitosan / silica coated material
By preparing porous polyethyleneimine-silver nanoclusters/chitosan/silica coated materials and performing etching treatment, the problem of insufficient sensing ability of metal nanocluster composite nanoparticles in the prior art has been solved, and the application in fluorescence sensing has been improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANAN UNIV
- Filing Date
- 2022-07-26
- Publication Date
- 2026-07-14
AI Technical Summary
The existing silica-coated metal nanoclusters composite nanoparticles have poor sensing properties in fluorescence sensing, which limits their application.
By preparing porous polyethyleneimine-silver nanoclusters/chitosan/silica coated materials and etching them at room temperature, a loose porous structure is formed, which enhances their sensing ability.
It improves the sensing performance of materials in fluorescence sensing, solves the problem of poor sensing performance, and is simple to operate, has mild conditions, and is easy to control the aperture.
Smart Images
Figure CN117483754B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing a coating material, specifically a method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coating material. Background Technology
[0002] Silica nanoparticles have found applications in numerous fields due to their excellent chemical stability and biocompatibility, ease of modification, and tunable specific surface area, pore size, and particle size. Composite fluorescent silica nanoparticles, obtained by coating fluorescent groups onto silica nanoparticles through doping, exhibit more advantages in physicochemical properties compared to the fluorescent groups themselves and ordinary nanomaterials. For example, silica is stable and optically transparent; coating increases the stability of the luminescent group without altering its luminescence properties. A single fluorescent silica nanoparticle can be coated with multiple fluorescent groups, significantly enhancing the fluorescent signal and greatly improving detection sensitivity. Coating with different colored luminescent materials allows for dual-color and multi-color labeling, facilitating the construction of ratiometric fluorescent sensors. The ease of modification of the silica surface facilitates the connection of specific molecules, resulting in strong specificity.
[0003] Metal nanoclusters are a novel type of nanomaterial, typically composed of several to dozens of metal atoms. Due to their size being close to the electron Fermi wavelength, they possess discrete electronic energy levels and molecular-like properties, such as inherent magnetism, the ability to switch between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, quantum capacitance charging effects, high catalytic activity, large Stokes shifts, and strong luminescence. These unique and excellent properties have led to the widespread application of metal nanoclusters in various fields, including biosensing, medical therapy, electronic devices, and energy catalysis. Fluorescence, as one of the important properties of metal nanoclusters, has attracted considerable attention from researchers. Tunable fluorescence from the visible to near-infrared region, high quantum yield, excellent photostability, simple and easy preparation methods, and ease of surface functionalization make metal nanoclusters a novel class of fluorescent nanomaterials. They are used in the design and fabrication of various fluorescent probes and have found wide applications in ion, drug, and small molecule detection and bioimaging.
[0004] However, metal nanoclusters suffer from drawbacks such as easy aggregation and susceptibility of optical properties to external environmental influences. Silica coating of metal nanoclusters can effectively prevent environmental impacts, inhibit aggregation, and improve stability. Therefore, some researchers have combined metal nanoclusters with silica to prepare metal nanocluster-doped silica composite nanoparticles. While these composite nanoparticles increase the stability of the metal nanoclusters, their sensing performance is often poor, limiting their application in fluorescence sensing. Summary of the Invention
[0005] The purpose of this invention is to overcome the problem that existing silica-coated metal nanocluster composite nanoparticles have poor sensing properties and are limited in their application in fluorescence sensing.
[0006] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows:
[0007] A method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated material is provided. This method includes etching the prepared porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles to make them porous and enhance their sensing ability. This solves the problem that existing silica-coated metal nanocluster composite nanoparticles have poor sensing properties, limiting their application in fluorescence sensing. The specific steps are as follows:
[0008] A method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material includes the following steps:
[0009] S1. Preparation of silver nanocluster solution;
[0010] S2. Prepare polyvinylimide-silver nanoclusters / chitosan / silica-coated nanoparticles, disperse the nanoparticles in ultrapure water, and store them under cold for later use;
[0011] S3. At room temperature, the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles are etched to obtain etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles. The etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles are then dispersed in pure water to obtain porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated materials.
[0012] Furthermore, the method for preparing the silver nanocluster solution in step S1 is as follows: after stirring and mixing 0.1 g / mL PEI solution and ultrapure water, add 0.01 mol / L silver nitrate solution, continue stirring, add reducing agent, stir again to obtain silver nanocluster solution, let stand until the silver nanocluster solution is stable, and then filter with a syringe filter.
[0013] Further, the method for preparing polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles in step S2 is as follows: Cyclohexane, n-hexanol, and Triton X-100 are mixed evenly, and then a silver nanocluster solution is added as the dispersed phase. The mixture is stirred to form a uniform and stable water-in-oil microemulsion. Then, 100 μL of 0.1% chitosan solution is added, and the pH of the system is adjusted to neutral after stirring. Stirring is continued, followed by the addition of tetraethyl orthosilicate and ammonia. After stirring at room temperature for 24 hours, acetone is added to break the emulsion. The nanoparticles are then separated by centrifugation and collected. The residual unreacted reagents adsorbed on the surface of the nanoparticles are then removed. Finally, the nanoparticles are dispersed in ultrapure water and then refrigerated for later use.
[0014] Furthermore, the etching method in step S3 is as follows: the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles are dispersed in ultrapure water, then NaOH solution is added, and after standing for etching for a period of time, they are washed once with ultrapure water and centrifuged to obtain the etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles.
[0015] Furthermore, the reducing agent in step S1 is 0.1 mol / L ascorbic acid.
[0016] Furthermore, in step S1, the volume ratio of PEI solution, ultrapure water, silver nitrate solution, and ascorbic acid is 1:0.5:2.5:1.
[0017] Furthermore, the volume of pure water in step S3 is 20 mL.
[0018] Furthermore, in step S3, polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles are dispersed in ultrapure water, wherein the volume of ultrapure water is 27 mL.
[0019] Furthermore, the etching time in step S3 is 5-30 minutes.
[0020] Furthermore, in step S3, the volume of the NaOH solution is 3 mL and the concentration is 0.05 mol / L.
[0021] The beneficial effects of this invention are:
[0022] The present invention incorporates an etching step into the preparation method of a porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated material. The prepared porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles are etched to make them loose and porous, thereby enhancing their sensing ability. This solves the problem that existing silica-coated metal nanocluster composite nanoparticles have poor sensing properties and are limited in their application in fluorescence sensing.
[0023] The etching method of the present invention for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coating material is simple, mild, and low in toxicity. It can react at room temperature, is easy to operate, and the pore size of the polyethyleneimine-silver nanoclusters / chitosan / silica coating material can be controlled by controlling the reaction time. Attached Figure Description
[0024] Figure 1 Transmission electron microscope image of unetched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles;
[0025] Figure 2Transmission electron microscope image of polyvinylimide-silver nanoclusters / chitosan / silica-coated nanoparticles after etching for 5 min;
[0026] Figure 3 Transmission electron microscope image of polyvinylimide-silver nanoclusters / chitosan / silica-coated nanoparticles after 10 min of etching;
[0027] Figure 4 Transmission electron microscope image of polyvinylimide-silver nanoclusters / chitosan / silica-coated nanoparticles after 15 min of etching;
[0028] Figure 5 Transmission electron microscope image of polyvinylimide-silver nanoclusters / chitosan / silica-coated nanoparticles after 20 min of etching;
[0029] Figure 6 Transmission electron microscope image of polyvinylimide-silver nanoclusters / chitosan / silica-coated nanoparticles after 30 min of etching;
[0030] Figure 7 A comparison of the relative fluorescence intensity of polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles before and after etching;
[0031] Figure 8 The fluorescence intensity stability diagram of porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles. Detailed Implementation
[0032] The following will refer to the appendix. Figure 1-8 Exemplary embodiments of this disclosure will be described in more detail below. While exemplary embodiments of this disclosure are shown in the accompanying drawings, it should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.
[0033] A method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material specifically includes the following steps:
[0034] S1. Place a clean, dry synthesis flask on a magnetic stirrer, add 1.00 mL of 0.1 g / mL PEI solution and 0.5 mL of ultrapure water, stir for 2 min, mix thoroughly, then add 2.50 mL of 0.01 mol / L silver nitrate solution, continue stirring for 2 min, and finally add 0.10 mol / L 1.00 mL of ascorbic acid and stir for 2 min to obtain a light yellow silver nanocluster solution. After standing for one week to stabilize, filter using a 0.2 μm syringe filter.
[0035] 7.5 mL of cyclohexane, 1.8 mL of n-hexanol, and 1.8 mL of Triton X-100 were mixed thoroughly. Then, 200 μL of silver nanoclusters solution was added as the dispersed phase, and the mixture was stirred to form a homogeneous and stable water-in-oil microemulsion. Next, 100 μL of 0.1% chitosan solution was added, and after stirring for 1 hour, NaOH solution was slowly added to adjust the pH to neutral, followed by stirring for another hour. Finally, 100 μL of tetraethyl orthosilicate and 70 μL of ammonia were added, and the mixture was stirred at room temperature for 24 hours. After the reaction was complete, 8 mL of acetone was added to break the emulsion. The mixture was centrifuged (8000 rpm for 5 min) and the nanoparticles were collected. The nanoparticles were then washed sequentially with anhydrous ethanol (20 mL, washed twice) and ultrapure water (20 mL, washed once) to remove residual unreacted reagents adsorbed on the nanoparticle surface. Finally, the nanoparticles were dispersed in 20 mL of ultrapure water and refrigerated for later use.
[0036] S3. At room temperature, disperse the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles in 27 mL of pure water, then add 3 mL of 0.05 mol / L NaOH solution, let stand for 5–30 min, centrifuge and wash once with ultrapure water (20 mL) to obtain etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles, and disperse them in 20 mL of pure water.
[0037] Compare with Example 1
[0038] At room temperature, the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were dispersed in 20 mL of pure water without the addition of 0.05 mol / L NaOH solution for etching.
[0039] The polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles do not have obvious pore structures, such as Figure 1 As shown.
[0040] Example 1
[0041] At room temperature, the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were dispersed in 27 mL of pure water, and then 3 mL of 0.05 mol / L NaOH solution was added. After standing for 5 min, the nanoparticles were washed once with ultrapure water (20 mL) and centrifuged to obtain the etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles, which were then dispersed in 20 mL of pure water.
[0042] The polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles exhibit a distinct porous structure, such as Figure 2 As shown.
[0043] Example 2
[0044] At room temperature, the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were dispersed in 27 mL of pure water, and then 3 mL of 0.05 mol / L NaOH solution was added. After standing for 10 min, the nanoparticles were washed once with ultrapure water (20 mL) and centrifuged to obtain the etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles, which were then dispersed in 20 mL of pure water.
[0045] The polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticle structure gradually dissociates, but still retains a relatively intact structure, such as... Figure 3 As shown.
[0046] Example 3
[0047] At room temperature, the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were dispersed in 27 mL of pure water, and then 3 mL of 0.05 mol / L NaOH solution was added. After standing for 15 min, the etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were obtained by centrifugation and washing once with ultrapure water (20 mL). The etched nanoparticles were then dispersed in 20 mL of pure water.
[0048] The structure of the polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles clearly dissociates, such as Figure 4 As shown.
[0049] Example 4
[0050] At room temperature, the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were dispersed in 27 mL of pure water, and then 3 mL of 0.05 mol / L NaOH solution was added. After standing for 20 min, the nanoparticles were obtained by centrifugation and washing once with ultrapure water (20 mL). The etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were then dispersed in 20 mL of pure water.
[0051] The core-shell structure of the polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles clearly dissociated, with the nanoparticles essentially absent; some polyethyleneimine-silver nanoclusters were dispersed in the solution, such as... Figure 5 As shown.
[0052] Example 5
[0053] At room temperature, the prepared polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were dispersed in 27 mL of pure water, and then 3 mL of 0.05 mol / L NaOH solution was added. After standing for 30 min, the nanoparticles were obtained by centrifugation and washing once with ultrapure water (20 mL). The etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were then dispersed in 20 mL of pure water.
[0054] The structure of the polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles clearly dissociated, with a large number of polyethyleneimine-silver nanoclusters dispersed in the solution, such as... Figure 6 As shown.
[0055] To further verify that the product of this invention is porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles, the inventors provided the following experimental example:
[0056] 1. Comparison of fluorescence intensity of polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles before and after etching with NaOH solution
[0057] The fluorescence intensity of the polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles prepared in Comparative Example 1 and Example 1 was compared and measured. Figure 7 As shown, the fluorescence intensity was normalized, indicating that the porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles prepared in Example 1 have strong fluorescence intensity.
[0058] 2. Fluorescence stability determination
[0059] The fluorescence stability of the porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles prepared in Example 1 was measured. Figure 8 As shown, fluorescence measurements of porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles were performed from 0 to 168 hours, indicating that their fluorescence intensity was stable.
[0060] Although five preferred embodiments of the present invention have been disclosed and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material, characterized in that, Includes the following steps: S1, Preparation of a polyethyleneimine-stabilized silver nanocluster solution; S2, Preparation of Polyethyleneimine-Silver Nanoclusters / Chitosan / Silica-Coated Nanoparticles: The method is as follows: Cyclohexane, n-hexanol and Triton X-100 are mixed evenly and then added to the polyethyleneimine-stabilized silver nanocluster solution prepared in step S1 as the dispersed phase. The mixture is stirred to form a uniform and stable water-in-oil microemulsion. Then, 100 µL of 0.1% chitosan solution is added. After stirring, the pH of the system is adjusted to neutral and stirring is continued. Then, tetraethyl orthosilicate and ammonia are added. After stirring at room temperature for 24 hours, acetone is added to break the emulsion. The nanoparticles are separated by centrifugation and collected. Then, the residual unreacted reagents adsorbed on the surface of the nanoparticles are removed. Finally, the nanoparticles are dispersed in ultrapure water and then refrigerated for later use. S3, at room temperature, disperse the polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles prepared in step S2 in ultrapure water, add NaOH solution and allow to stand for etching to obtain etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles, disperse them in ultrapure water to obtain porous polyethyleneimine-silver nanoclusters / chitosan / silica-coated materials; The etching time is 5-30 minutes.
2. The method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material according to claim 1, characterized in that: The method for preparing the polyethyleneimine-stabilized silver nanocluster solution in step S1 is as follows: 0.1 g / mL PEI solution and ultrapure water are stirred and mixed, then 0.01 mol / L silver nitrate solution is added, and after stirring, a reducing agent is added. After stirring again, the silver nanocluster solution is obtained. After standing until the silver nanocluster solution is stable, it is filtered with a syringe filter.
3. The method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material according to claim 2, characterized in that... The reducing agent in step S1 is 0.1 mol / L ascorbic acid.
4. The preparation method of a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material according to claim 3, characterized in that... In step S1, the volume ratio of PEI solution, ultrapure water, silver nitrate solution and ascorbic acid is 1:0.5:2.5:
1.
5. The preparation method of a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material according to claim 1, characterized in that: In step S3, the etched polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles are dispersed in ultrapure water, and the volume of the ultrapure water is 20 mL.
6. The method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material according to claim 1, characterized in that... In step S3, polyethyleneimine-silver nanoclusters / chitosan / silica-coated nanoparticles are dispersed in ultrapure water, wherein the volume of ultrapure water is 27 mL.
7. The method for preparing a porous polyethyleneimine-silver nanoclusters / chitosan / silica coated material according to claim 1, characterized in that... In step S3, the volume of the NaOH solution is 3 mL and the concentration is 0.05 mol / L.