Microfluidic device, application and preparation method of silver-coated gold cubic nanoparticles
By precisely controlling the flow rate and concentration using a microfluidic device, silver-coated gold cubic nanoparticles were synthesized, solving the problems of size inhomogeneity and low efficiency in traditional methods. This resulted in efficient and simple nanoparticle synthesis with a good SERS effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA JILIANG UNIV
- Filing Date
- 2023-04-12
- Publication Date
- 2026-04-17
AI Technical Summary
Traditional methods are difficult to control reaction conditions precisely, resulting in uneven size distribution and low synthesis efficiency of silver-coated gold cubic nanoparticles, and the operation is complicated.
A microfluidic device design was adopted to synthesize silver-coated gold cubic nanoparticles by precisely controlling the flow rate and concentration using a microfluidic chip, including a defined inlet and a premixing zone, and the use of an S-shaped channel to increase the reaction mixing efficiency.
The reaction efficiency was improved, the operation was simplified, and the synthesized silver-coated gold cubic nanoparticles had uniform morphology and good SERS effect, making them suitable for Raman detection.
Smart Images
Figure CN121869475A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nanomaterials technology, and more specifically to a microfluidic device and its application, particularly to the synthesis of silver-coated gold cubic nanoparticles with SERS effect based on microfluidic technology. Background Technology
[0002] Nanomaterials, due to their unique optical, electrical, thermal, chemical, and mechanical properties, have wide applications in nanoelectronic devices, medicine and health, aerospace and space exploration, environment, resources and energy, and biotechnology. Noble metal nanoparticles, with their unique localized surface plasmon resonance (LSPR) properties, have attracted widespread attention and application in medical detection, biosensing, and many other fields. Gold-core silver-shell nanoparticles have attracted interest due to their structural stability and the synergistic effect of core-shell physicochemical properties, showing broad application prospects in Raman spectroscopy. Noble metal nanoparticles of different shapes exhibit variable LSPR properties, while cubes, due to their sharp edges, possess excellent LSPR characteristics; nanocubes have been shown to exhibit excellent surface-enhanced Raman (SERS) signals due to their sharp edges.
[0003] Traditional methods for synthesizing nanoparticles in beakers suffer from low production efficiency due to the inability to precisely control reactant concentrations and reaction conditions, as well as other unavoidable external environmental influences. The synthesized core-shell nanoparticles exhibit uneven size distribution and irregular growth. In the conventional preparation of silver-coated gold (Au@Ag) core-shell nanoparticles, manual addition of silver nitrate solution is required, which can introduce errors that lead to uneven nanoparticle growth. Furthermore, stirring time must exceed thirty minutes to achieve full synthesis of Au@Ag nanoparticles.
[0004] Microfluidics, as an effective tool for synthesizing nanoparticles, can precisely regulate reaction conditions within a confined space. Especially for nanoparticles with specific morphologies and composite structures, microfluidic chips are excellent synthetic reactors, capable of integrating multi-step reactions within a micrometer-scale chip, improving reaction efficiency while avoiding interference from the external environment.
[0005] Therefore, how to provide a device and method for synthesizing silver-coated gold cubic nanoparticles with SERS effect based on microfluidic technology is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0006] In view of this, the present invention provides a microfluidic device and a method for preparing silver-coated gold cubic nanoparticles using the device. In order to synthesize silver-coated gold cubic nanoparticles with SERS effect, the present invention specifically designed a microfluidic chip, limiting the number of inlet ports and premixed zones, etc., and synthesized silver-coated gold cubic nanoparticles by precisely controlling the flow rate and concentration.
[0007] This invention not only improves reaction efficiency and provides a simple and quick operation method while saving reagents, but also produces silver-coated gold cubic nanoparticles with uniform morphology. Using the synthesized silver-coated gold cubic nanoparticles as a SERS substrate, Raman detection of different concentrations of methylene blue was performed, and the nanoparticles exhibited a good SERS effect.
[0008] One objective of this invention is to provide a microfluidic device, specifically comprising: a substrate layer, and a main chip fixed on the substrate layer;
[0009] The main chip includes: sample inlet 1, sample inlet 2, sample inlet 3, sample inlet 4, premixing zone 1, premixing zone 2, and sample outlet;
[0010] The first and second injection ports converge into the first premixing zone;
[0011] The first premixing zone is connected to the second premixing zone via a microfluidic channel;
[0012] The three and four inlets converge into the premixing zone two;
[0013] The second premixing zone is connected to the sample outlet via the second microfluidic channel;
[0014] A catheter is inserted into each of the four inlet ports, and each catheter is connected to a syringe. The syringe is controlled by an injection pump to control the liquid injection rate.
[0015] Preferably, the thickness of the main chip is 3 mm and the material is polydimethylsiloxane; the substrate layer is glass.
[0016] Preferably, the width of both the first microfluidic channel and the second microfluidic channel is 300 micrometers;
[0017] Both the first microfluidic channel and the second microfluidic channel are S-shaped channels;
[0018] The path of the first microfluidic channel is shorter than the path of the second microfluidic channel.
[0019] A catheter is inserted into the sample outlet, and the catheter is connected to a product collection vessel.
[0020] The beneficial effects of adopting the above technical solution include at least the following: the S-shaped channel can increase the channel length in a limited space, making the reaction more complete, transforming laminar flow into turbulent flow, and improving mixing efficiency.
[0021] The second objective of this invention is the application of the microfluidic device in the preparation of silver-coated gold cubic nanoparticles.
[0022] The third objective of this invention is to provide a method for preparing silver-coated gold cubic nanoparticles, specifically including the following steps:
[0023] 1) At the same time, add gold seed solution and hexadecyltrimethylammonium chloride solution to injection port one and injection port two respectively, and after preliminary mixing in premixing zone one, flow through microfluidic channel one for thorough mixing;
[0024] 2) Simultaneously, silver nitrate solution and mixed solution are added to inlet three and inlet four respectively, and premixed with the reaction synthesis solution obtained in step 1) in premixing zone two. After being fully mixed and reacted through microfluidic channel two, the reaction solution is collected through the outlet and centrifuged to obtain silver-coated gold cubic nanoparticles.
[0025] The mixture is a mixture of ascorbic acid and hexadecyltrimethylammonium chloride.
[0026] Preferably, the flow rate of the gold seed solution in step 1) is 20 μL / min; the flow rate of the 20 mM hexadecyltrimethylammonium chloride solution is 0.18 mL / min.
[0027] Preferably, in step 2), the concentration of the silver nitrate solution is 0.5 mM and the flow rate is 0.18 mL / min; the concentration of ascorbic acid in the mixture is 50 mM, the concentration of hexadecyltrimethylammonium chloride is 40 mM, and the flow rate is 0.18 mL / min.
[0028] Preferably, in step 2), the centrifugation speed is 14500 r / min and the time is 30 min.
[0029] Preferably, the gold seed solution in step 1) is obtained through a traditional gold seed synthesis method, specifically: First, 0.6 mL of freshly prepared NaBH4 solution (10 mM) is added to 10 mL of water containing HAuCl4 (0.25 mM) and CTAB (100 mM) to prepare 3 nm gold seeds, producing a brown solution. The brown 3 nm gold seed solution is kept undisturbed at 27°C for 3 hours to ensure complete decomposition of the remaining NaBH4 in the solution. Then, 6 mL of HAuCl4 solution (0.5 mM), 6 mL of CTAC solution (200 mM), and 4.5 mL of AA solution (100 mM) are mixed, and then 0.3 mL of 3 nm gold nanoparticle solution is added. The final mixture changes from colorless to red within 1 minute, and is centrifuged at 14500 r / min for 30 minutes to obtain the gold seed solution required for the experiment.
[0030] Preferably, the microfluidic device is placed on a heating plate, and the temperature is controlled at 55-65°C to complete the entire reaction process. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0032] Figure 1 This is a schematic diagram of the main chip structure of the microfluidic device in Example 1;
[0033] Figure 2 SEM characterization image of the silver-coated gold cubic nanoparticles prepared in Example 2;
[0034] Figure 3 These are TEM and EDS mapping images of a single silver-coated gold cubic nanoparticle.
[0035] Figure 4 It uses silver-coated gold cubic nanoparticles as a substrate to test different concentrations (10) -6 M-10 -10 The results of methylene blue SERS detection (M);
[0036] Figure 5 The particle size distribution diagram of the silver-coated gold cubic nanoparticles prepared in Example 2;
[0037] Figure 6 SEM characterization image of the silver-coated gold cubic nanoparticles prepared in Comparative Example 1;
[0038] Figure 7 SEM characterization image of the silver-coated gold cubic nanoparticles prepared in Comparative Example 2;
[0039] Figure 8 Comparison of UV absorption spectra of silver-coated gold cubic nanoparticles prepared in Comparative Examples 3-6 and Example 2.
[0040] Figure 9 This is a comparison chart of the reaction results of Comparative Example 7 and Example 2.
[0041] In the diagram:
[0042] 1 is the first injection port, 2 is the second injection port, 3 is the first premixing zone, 4 is the third injection port, 5 is the fourth injection port, 6 is the second premixing zone, 7 is the outlet port, 8 is the first microfluidic channel, and 9 is the second microfluidic channel. Detailed Implementation
[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0044] Example 1
[0045] This embodiment provides a microfluidic device for preparing silver-coated gold cubic nanoparticles, specifically including: a substrate layer, and a main chip fixed on the substrate layer;
[0046] The main chip includes: Inlet 1, Inlet 2, Inlet 3, Inlet 4, Inlet 4, Premixing Zone 1, Premixing Zone 2, and Outlet 7;
[0047] Inlet 1 and Inlet 2 converge into premixing zone 3;
[0048] Premixing zone 3 is connected to premixing zone 6 via microfluidic channel 8;
[0049] Inlet 3 (4) and inlet 4 (5) converge into premixing zone 2 (6);
[0050] Premixing zone 26 is connected to sample outlet 7 via microfluidic channel 29;
[0051] A tubing is inserted into each of the four injection ports: 1, 2, 4, and 5. The tubing is connected to a syringe, and the injection speed of the syringe is controlled by an injection pump.
[0052] To further optimize the above technical solution, the thickness of the main chip is 3mm and the material is polydimethylsiloxane; the substrate layer is glass.
[0053] To further optimize the above technical solution, the pore diameter of both microfluidic channel 1 8 and microfluidic channel 2 9 is 300 micrometers;
[0054] Microfluidic channel 1 (8) and microfluidic channel 2 (9) are both S-shaped channels;
[0055] The path of microfluidic channel 1 (8) is shorter than the path of microfluidic channel 2 (9).
[0056] Insert a tubing into the sample outlet 7, and connect the tubing to the product collection vessel.
[0057] Example 2
[0058] This embodiment discloses a method for preparing silver-coated gold cubic nanoparticles, which specifically includes the following steps:
[0059] 1) At the same time, add gold seed solution and hexadecyltrimethylammonium chloride solution to injection port one and injection port two respectively, and after preliminary mixing in premixing zone one, flow through microfluidic channel one for thorough mixing;
[0060] 2) Simultaneously, silver nitrate solution and mixed solution are added to inlet three and inlet four respectively, and premixed with the reaction synthesis solution obtained in step 1) in premixing zone two. After being fully mixed and reacted through microfluidic channel two, the reaction solution is collected through the outlet and centrifuged to obtain silver-coated gold cubic nanoparticles.
[0061] The further mixing solution is a mixture of ascorbic acid and hexadecyltrimethylammonium chloride.
[0062] To further optimize the above technical solution, in step 1), the flow rate of the gold seed solution is 20 μL / min; the flow rate of the 20 mM hexadecyltrimethylammonium chloride solution is 0.18 mL / min.
[0063] To further optimize the above technical solution, in step 2), the concentration of silver nitrate solution is 0.5 mM and the flow rate is 0.18 mL / min; the concentration of ascorbic acid in the mixture is 50 mM, the concentration of hexadecyltrimethylammonium chloride is 40 mM, and the flow rate is 0.18 mL / min.
[0064] To further optimize the above technical solution, step 2) centrifugation speed is 14500 r / min, time is 30 min.
[0065] To further optimize the above technical solution, step 1) involves obtaining the gold seed solution using a traditional gold seed synthesis method. Specifically, 0.6 mL of freshly prepared NaBH4 solution (10 mM) is added to 10 mL of water containing HAuCl4 (0.25 mM) and CTAB (100 mM) to prepare 3 nm gold seeds, resulting in a brown solution. This brown 3 nm gold seed solution is kept undisturbed at 27°C for 3 hours to ensure complete decomposition of any remaining NaBH4. Next, 6 mL of HAuCl4 solution (0.5 mM), 6 mL of CTAC solution (200 mM), and 4.5 mL of AA solution (100 mM) are mixed, followed by the addition of 0.3 mL of the 3 nm gold nanoparticle solution. The final mixture changes from colorless to red within 1 minute. It is then centrifuged at 14500 r / min for 30 minutes to obtain the desired gold seed solution.
[0066] To further optimize the above technical solution, the microfluidic device is placed on a heating plate and the temperature is controlled at 60°C to complete the entire reaction process.
[0067] The silver-coated gold cubic nanoparticles prepared according to Example 2 were characterized by SEM, such as... Figure 2As shown, the uniform morphology of the silver-coated gold cube nanoparticles can be clearly seen.
[0068] TEM characterization of the prepared silver-coated gold cubic nanoparticles clearly showed that the synthesized silver-coated gold cubic nanoparticles had a gold core and silver shell structure. EDS mapping results clearly showed the distribution of gold and silver elements. Figure 3 As shown.
[0069] 10 μL of the silver-coated gold cubic nanoparticle solution prepared in Example 2 was dropped onto a 5 mm * 5 mm silicon wafer and vacuum dried at 60 °C to obtain a SERS substrate. 10 μL of different concentrations of 10... -6 M-10 -10 Raman spectroscopy was performed on a methylene blue solution of M using a 633 nm laser source, with an integration time of 10 s and one integration iteration. The experimental results are as follows: Figure 4 As shown, a concentration of 10 can be detected. -6 M-10 -10 Methylene blue of M was used to demonstrate that the prepared silver-coated gold cubic nanoparticles exhibited a good SERS effect.
[0070] Comparative Example 1
[0071] The only difference from Example 2 is that, in step 2), the concentration of ascorbic acid in the mixture is 10 mM.
[0072] Comparative Example 2
[0073] The only difference from Example 2 is that, in step 2), the concentration of ascorbic acid in the mixture is 30 mM.
[0074] The silver-coated gold cubic nanoparticles prepared according to Comparative Examples 1-2 were characterized by SEM, such as... Figure 6-7 As shown, when the ascorbic acid concentration is 10 mM and 30 mM, a large amount of bulk material is generated, which is insufficient to reduce it into smaller nanoparticles.
[0075] Comparative Example 3
[0076] The only difference from Example 2 is that the microfluidic device is placed on a heating plate and the temperature is controlled at 30°C to complete the entire reaction process.
[0077] Comparative Example 4
[0078] The only difference from Example 2 is that the microfluidic device is placed on a heating plate and the temperature is controlled at 45°C to complete the entire reaction process.
[0079] Comparative Example 5
[0080] The only difference from Example 2 is that the microfluidic device is placed on a heating plate and the temperature is controlled at 75°C to complete the entire reaction process.
[0081] Comparative Example 6
[0082] The only difference from Example 2 is that the microfluidic device is placed on a heating plate and the temperature is controlled at 90°C to complete the entire reaction process.
[0083] The ultraviolet absorption spectra of the silver-coated gold cubic nanoparticles prepared in Comparative Examples 3-6 and Example 2 are shown in Figure 8. It can be seen that the full width at half maximum (FWHM) of the ultraviolet absorption peak is narrowest when the temperature is 60℃, indicating that the synthesized particles are more uniform.
[0084] Comparative Example 7
[0085] The difference from Example 2 is as follows:
[0086] Step 1) The flow rate of the gold seed solution is 40 μL / min; the flow rate of the 20 mM hexadecyltrimethylammonium chloride solution is 0.36 mL / min.
[0087] Step 2) The concentration of silver nitrate solution is 0.5 mM and the flow rate is 0.36 mL / min; the concentration of ascorbic acid in the mixture is 50 mM and the concentration of hexadecyltrimethylammonium chloride is 40 mM, and the flow rate is 0.36 mL / min.
[0088] The reaction products of Comparative Example 7 and Example 2 were obtained respectively, as follows: Figure 9 As shown; the left side is the reaction result of Comparative Example 7, and the right side is the reaction result of Example 2.
[0089] The parts of this invention not described in detail in the embodiments can be implemented using existing technologies, and will not be elaborated here.
[0090] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0091] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A microfluidic device, characterized in that, include: A substrate layer, and a main chip fixed on the substrate layer; The main chip includes: sample inlet 1, sample inlet 2, sample inlet 3, sample inlet 4, premixing zone 1, premixing zone 2, and sample outlet; The first and second injection ports converge into the first premixing zone; The first premixing zone is connected to the second premixing zone via a microfluidic channel; The three and four inlets converge into the premixing zone two; The second premixing zone is connected to the sample outlet via the second microfluidic channel; A catheter is inserted into each of the four inlet ports, and each catheter is connected to a syringe. The syringe is controlled by an injection pump to control the liquid injection rate.
2. The microfluidic device according to claim 1, characterized in that, The width of both the first microfluidic channel and the second microfluidic channel is 300 micrometers; Both the first microfluidic channel and the second microfluidic channel are S-shaped channels; The path length of the first microfluidic channel is shorter than that of the second microfluidic channel.
3. The microfluidic device according to claim 1, characterized in that, A catheter is inserted into the sample outlet, and the catheter is connected to a product collection vessel.
4. The application of the microfluidic device according to any one of claims 1-3 in the preparation of silver-coated gold cubic nanoparticles.
5. A method of preparing silver-coated gold cubic nanoparticles, characterized by, The preparation of silver-coated gold cubic nanoparticles using the microfluidic device according to any one of claims 1-3 specifically includes the following steps: 1) At the same time, add gold seed solution and hexadecyltrimethylammonium chloride solution to injection port one and injection port two respectively, and after preliminary mixing in premixing zone one, flow through microfluidic channel one for thorough mixing; 2) Simultaneously, silver nitrate solution and mixed solution are added to inlet three and inlet four respectively, and premixed with the reaction synthesis solution obtained in step 1) in premixing zone two. After being fully mixed and reacted through microfluidic channel two, the reaction solution is collected through the outlet and centrifuged to obtain silver-coated gold cubic nanoparticles. The mixture is a mixture of ascorbic acid and hexadecyltrimethylammonium chloride.
6. The method for preparing silver-coated gold cubic nanoparticles according to claim 5, characterized in that, The flow rate of the gold seed solution in step 1) is 20 μL / min; The concentration of the hexadecyltrimethylammonium chloride was 20 mM, and the flow rate was 0.18 mL / min.
7. The method for preparing silver-coated gold cubic nanoparticles according to claim 5, characterized in that, Step 2) The concentration of the silver nitrate solution is 0.5 mM, and the flow rate is 0.18 mL / min; The mixture contains 50 mM ascorbic acid, 40 mM hexadecyltrimethylammonium chloride, and a flow rate of 0.18 mL / min.
8. The method for preparing silver-coated gold cubic nanoparticles according to claim 5, characterized in that, Step 2) The centrifugation speed is 14500 r / min and the time is 30 min. 9.The method of claim 5, wherein the gold is coated on the silver cubic nanoparticles by a chemical reduction method. The gold seed solution in step 1) is obtained by a traditional gold seed synthesis method.
10. A method for preparing silver-coated gold cubic nanoparticles according to any one of claims 6-9, characterized in that, The microfluidic device is placed on a heating plate, and the temperature is controlled at 55-65℃ to complete the entire reaction process.