High-sensitivity wettability heating SERS substrate based on fish scale-like structure and preparation method thereof
By designing a SERS substrate with a fish-scale-like structure and heating function, the problems of high cost and low efficiency are solved, enabling high-throughput, low-cost trace substance detection with a detection limit of 10⁻¹⁶M, suitable for high-sensitivity detection of environmental pollutants and biomolecules.
Patent Information
- Application Number
- CN202511495445.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2025-11-28
AI Technical Summary
Existing SERS substrates are expensive to prepare, have limited wettability control, and low enrichment efficiency, making it impossible to achieve high-throughput detection and failing to meet trace detection needs.
A highly sensitive wettability heating SERS substrate with a fish-scale-like structure is used. Combined with a copper substrate and a glass substrate, a fish-scale-like and grooved structure is prepared by ultraviolet nanosecond laser. A modified layer and a silver film are then covered, along with a silver nanowire layer. The substrate is fixed with non-conductive double-sided tape to achieve superhydrophobic high adhesion and superhydrophobic low adhesion properties. Combined with the heating function, the liquid evaporation is accelerated.
It significantly improves detection efficiency, shortens evaporation time, achieves high-throughput detection, has a detection limit of 10⁻¹⁶M, reduces equipment costs, avoids sample loss, and is suitable for high-sensitivity detection of trace substances.
Smart Images
Figure CN121027074A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of surface-enhanced Raman scattering (SERS) detection, and particularly relates to a rapid concentration SERS substrate integrated with a biomimetic wetting structure and a heating function and a preparation method thereof, which is suitable for high-sensitivity and high-throughput detection of trace substances (such as environmental pollutants and biomolecules). BACKGROUND
[0002] Surface-enhanced Raman scattering (SERS) technology is widely used in the field of trace analysis due to its high sensitivity and fingerprint identification characteristics. The surface morphology, wettability and enrichment efficiency of the SERS substrate, as the core of the technology, directly determine the detection performance.
[0003] In the prior art, in order to realize wettability regulation to improve the enrichment effect, researchers use femtosecond laser to prepare a gradually changing wettability SERS substrate, but there are two major defects: ① the cost of femtosecond laser equipment is high (the price of a single device is more than 10 million yuan), which is difficult to industrialize and popularize; ② the super-hydrophobic surface causes the drying of the liquid to be tested to take a long time (usually more than 30 minutes), which seriously limits the detection efficiency. In addition, the conventional SERS substrate also has the following problems:
[0004] Single wettability regulation: mostly single hydrophobic or hydrophilic surface, which cannot realize "sample positioning" and "anti-flowing out" at the same time, and is easy to cause sample loss or cross contamination;
[0005] No heating enrichment function: relying on room temperature natural evaporation, low enrichment efficiency, difficult to meet the needs of trace detection (such as 10⁻¹ 5 M or below);
[0006] Low throughput: only one sample can be detected at a time, which cannot adapt to batch detection scenarios (such as drug screening and environmental monitoring).
[0007] Therefore, it is a technical problem urgently to be solved in the field to develop a SERS substrate with "low-cost preparation, rapid enrichment, high sensitivity and high throughput". SUMMARY
[0008] Therefore, the present application provides a high-sensitivity wetting and heating SERS substrate based on a fish scale structure and a preparation method thereof to solve the technical problems in the background art.
[0009] To achieve the above purpose, one of the present application provides the following technical scheme:
[0010] A highly sensitive wettability heated SERS substrate based on a fish-scale-like structure comprises an assembled SERS substrate and a heated substrate. The SERS substrate uses a copper substrate as its base, and the surface of the copper substrate has a fish-scale-like structure with multiple detection zones and a trench structure surrounding the detection zones. The surface of the copper substrate is sequentially covered with a 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFTS) modified layer and a silver film. The heated substrate uses a glass slide as its base, and the surface of the glass slide has a silver nanowire layer. The surface of the silver nanowire layer is covered with non-conductive double-sided adhesive tape. The SERS substrate is bonded and fixed to the heated substrate by the double-sided adhesive tape.
[0011] Furthermore, the silver nanowire layer is composed of silver nanowires with a diameter of 20-100 nm, a length of 10-20 μm, and a thickness of 3-5 μm, and the silver nanowires form a continuous conductive network on the surface of the glass sheet.
[0012] Furthermore, the fish-scale-like structure has superhydrophobic and high adhesion properties (a 5μL droplet still adheres when tilted 180° on a copper substrate), and the trench structure has superhydrophobic and low adhesion properties. The surface contact angle between the two regions is ≥150°, and the oxygen content in the fish-scale structure region is lower than that in the trench structure region.
[0013] Furthermore, the surface of the silver film is provided with silver nanoclusters: large clusters with a diameter of 200-300 nm are located at the junction of the groove structure, and small clusters with a diameter of 50-100 nm are located in the flat area of the fish scale structure.
[0014] Furthermore, the non-conductive double-sided tape has a thickness of 0.08-0.18mm, is made of medical-grade insulating material, and has a peel strength ≥2N / cm.
[0015] To achieve the above objectives, the second aspect of the present invention provides the following technical solution:
[0016] A method for preparing a highly sensitive wettability heated SERS substrate based on a fish-scale-like structure includes the following steps:
[0017] S1. Preparation of SERS substrate: A fish-scale structure and a trench structure were fabricated on a copper substrate using a 355nm ultraviolet nanosecond laser. After being soaked in a PFTS mixture and dried to form a modified layer, a 50-100nm thick silver film was sputtered by magnetron sputtering.
[0018] S2. Preparation of heating substrate: Spin-coat a mixture of 0.1-1.0 mg / mL silver nanowires and 5-20 mg / mL silver isopropoxide nanowires onto the surface of a glass slide 4-10 times to form a silver nanowire layer, and cover it with non-conductive double-sided adhesive tape;
[0019] S3. Assembly: Attach the SERS substrate to the double-sided adhesive tape of the heated substrate to obtain the target substrate.
[0020] Furthermore, the parameters for preparing the fish-scale-like structure in step S1 are: laser power 3-5W, scanning rate 200-400mm / s, number of scans 4-6, and processing spacing 0.03-0.07mm; the parameters for preparing the groove structure are: laser power 4-6W, scanning rate 30-70mm / s, number of scans 5-8, and processing spacing 0.04-0.08mm.
[0021] Furthermore, the glass slide in step S2 needs to be pretreated before spin coating: soak it in a mixture of hydrogen peroxide and concentrated sulfuric acid (volume ratio 1:3) for 20-60 minutes, rinse it with deionized water, and then blow it dry with nitrogen.
[0022] To achieve the above objectives, the third aspect of the present invention provides the following technical solution:
[0023] An application method for trace substance SERS detection using a highly sensitive wettability heating SERS substrate based on a fish-scale-like structure includes the following steps:
[0024] A. Add 5 μL of the test liquid to the fish scale-like detection area of the substrate according to any one of claims 1 to 5;
[0025] B. Apply a DC voltage to the silver nanowire layer to raise the temperature of the detection area to 50~100℃, thereby accelerating the evaporation and enrichment of the liquid;
[0026] C. Detection using a Raman spectrometer, with a detection limit of not less than 10. -16 M.
[0027] Furthermore, in step B, the DC voltage is 8-15V, and the time from the addition of the liquid to complete evaporation is ≤1 minute.
[0028] The beneficial effects of this invention are as follows:
[0029] 1. Detection efficiency has been significantly improved.
[0030] Evaporation time is significantly reduced:
[0031] Under conventional non-heating conditions, it takes 36 minutes to evaporate and enrich 5 μL of liquid; after heating at 70°C, the evaporation time is shortened to 56 seconds (an efficiency improvement of about 38 times).
[0032] High-throughput detection capability:
[0033] The substrate design includes nine detection areas with a diameter of 1 mm; the spacing between adjacent areas is 3 mm, supporting simultaneous detection of multiple samples.
[0034] The thermal imager shows that the temperature distribution in each detection area is uniform.
[0035] 2. Breakthrough in detection sensitivity
[0036] Ultra-low detection limit:
[0037] The detection limit for R6G probe molecules is 10⁻ 16 M, the characteristic peak is still clearly distinguishable at extremely low concentrations.
[0038] Signal enhancement mechanism:
[0039] Large Ag clusters are formed at the junction of gullies; silver particles are evenly distributed in the fish-scale structure region to form "hot spots"; elemental analysis shows that F, Si, O, C and Ag are evenly distributed.
[0040] 3. Replacing femtosecond lasers with ultraviolet nanosecond lasers reduces equipment costs by more than 60%, which is beneficial for industrialization.
[0041] 4. The fish-scale-like structure provides high adhesion (droplets do not slide when rotated 180°) + the groove structure provides superhydrophobicity to prevent flow-out, thus avoiding sample loss.
[0042] In summary, this invention creatively proposes a fish-scale-like structure and, under the guidance of professional theory and through repeated experimental verification, proposes a specific preparation process that results in low preparation cost, high production efficiency, and stable and reliable production quality. Based on this, a specific application method is proposed, thus realizing a complete R&D process from conception to specific preparation and then to practical application, pointing the way for the commercial implementation of this invention.
[0043] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0044] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:
[0045] Figure 1 (a) Process flow for rapid heating and high-throughput SERS substrate preparation; (b) SEM image of silver nanowires; (c) Thermal image of the sample on the heated substrate; (dⅠ) Schematic diagram of the sample planar structure and SEM images of the fish scale and groove structures, and processing speed; (dⅡ) Schematic diagram of processing parameters; (eⅠ) Optical image of the heated SERS substrate; (eⅡ) Optical thermal image of the heated SERS substrate; (eⅢ) Thermal image of the heated substrate;
[0046] Figure 2 (a) A planar schematic of the sample, and SEM images of the fish scale and groove structures, and processing speed; (b) A schematic diagram of the processing parameters.
[0047] Figure 3 (a) Optical image of heated SERS substrate; (b) Thermal image of heated substrate; (c) Optical thermal image of heated SERS substrate.
[0048] Figure 4 (a) SEM and magnified view of the SERS substrate trench structure; (b) EDX spectrum of the SERS substrate trench structure; (c) Overall mapping image of the layer and corresponding SEM image; (d) Distribution map of elements fluorine (F), silicon (Si), carbon (C), copper (Cu), silver (Ag) and oxygen (O);
[0049] Figure 5 (a) SEM and magnified view of the fish scale structure on the SERS substrate; (b) 5 μL droplet at different tilt angles; (c) EDX spectrum of the groove structure on the SERS substrate; (d) Overall and layered; (e) Mapped image and corresponding SEM image: including elements silicon (Si), carbon (C), oxygen (O), copper (Cu), silver (Ag) and fluorine (F).
[0050] Figure 6 (a) Schematic diagram of the evaporation enrichment process of the test liquid on the SERS substrate; (b) Image of the drying enrichment process of 5 μL of liquid heated to 70°C; (c) Image of the evaporation enrichment process of 5 μL of liquid without heating; (d) 5 μL 10 -9 -10 -12 The Raman spectrum of M's R6G; (e) 5 μL 10 -13 -10 -16 Raman spectra of M and R6G;
[0051] Figure 7 Heated SERS substrates and optical images at nine test sites;
[0052] Figure 8 SEM morphology images of the fish scale detection area and the groove area prepared under different laser scanning conditions, all scanned 5 times. Detailed Implementation
[0053] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0054] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.
[0055] like Figure 1 As shown, this embodiment provides a highly sensitive wettable heated SERS substrate based on a fish-scale-like structure. The highly sensitive wettable heated SERS substrate consists of two parts: a SERS substrate and a heated substrate. First, the SERS substrate is prepared. The preparation process is as follows: a fish-scale-like structure with four detection regions and adjacent trench structures is fabricated on a copper substrate using a 355 nm ultraviolet nanosecond laser. Then, the substrate marked with the ultraviolet nanosecond laser is immersed in a solution of 50 μL of PFTS and 20 ml of anhydrous ethanol for 2 hours, followed by drying in a drying oven for 4 hours to obtain a low surface energy substrate. Then, a silver thin film with a thickness of approximately 80 nm is sputtered using a magnetron sputtering device. This completes the preparation of the SERS substrate. The preparation process of the heated substrate is as follows: First, a clean glass slide is placed in a spin coater (CY-SPC4-A, Zhengzhou Chengyue Scientific Instruments Co., Ltd.). Then, 5 μL of silver nanowires (Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.) (silver nanowires mixed with 0.2 mg / ml of silver nanowires and 10 mg / ml of isopropanol for dilution) are dropped onto the glass slide and spin-coated for one minute. Then, another 5 μL of silver nanowires are dropped onto the slide and spin-coated for one minute. This process is repeated 6 times. Next, non-conductive double-sided tape is used to completely cover the silver nanowires, serving both a protective function and an adhesion function to the SERS substrate. Finally, the prepared SERS substrate is attached to a self-made silver nanowire heating plate. A heated and rapidly concentrated SERS substrate is thus prepared. A schematic diagram of the SERS substrate preparation and the heated substrate is shown below. Figure 1 As shown in (a). SEM images of silver nanowires on a heated substrate are shown in Figure 1. Figure 1 As shown in (b), the silver nanowires are uniformly and randomly distributed to ensure uniform surface heating in subsequent experiments, rapidly concentrating the SERS substrate as shown. Figure 1 As shown in (c, e).
[0056] The entire substrate design incorporates a fish-scale structure (the area for detecting the test liquid, exhibiting a superhydrophobic and highly adhesive state) and a trench structure (a trench structure to prevent the test liquid from flowing out when dry, exhibiting a superhydrophobic and low-adhesion state), as shown in the diagram. Figure 2 (a) As shown in the schematic diagram. The copper sheet used is 12×12mm in size, with four test areas of 1mm in diameter. The spacing between two adjacent test areas is 3mm. For details, please refer to [reference needed]. Figure 2(a) During the processing, the power of the ultraviolet nanosecond laser was set to 4W for both structures, the number of scans was 5, and the processing interval was 0.05mm. Figure 2 As shown in (b). However, there is a difference in processing speed between the two: the processing speed for the fish scale structure is 300 mm / s, while the processing speed for the groove structure is 50 mm / s. Under broader experimental conditions, in the ultraviolet nanosecond laser processing experiments, for the fish scale-like structure (superhydrophobic and highly adhesive), the laser power can be adjusted from 3W to 5W, the scanning speed is between 200 mm / s and 400 mm / s, the number of scans per sample is 4 to 6, and the processing spacing is controlled between 0.03 mm and 0.07 mm; while for the groove structure (superhydrophobic and low-adhesion), the laser power is adjusted to 4W to 6W, the scanning speed is reduced to 30 mm / s to 70 mm / s, the number of scans is increased to 5 to 8, and the processing spacing is slightly increased to 0.04 mm to 0.08 mm. All of the above experiments were conducted in air. Figure 8 SEM images of the fish scale detection area and the groove area prepared under different laser scanning conditions are shown.
[0057] The difference between high and low adhesion is mainly due to the microstructure and surface properties of the two structures. Under specific processing conditions (such as relatively high scanning rates), the fish-scale structure forms a unique microstructure that enhances the interaction between the liquid and the solid surface, making it easier for the liquid to spread and adhere, thus exhibiting high adhesion. In contrast, the groove structure, due to slower processing rates, has a different microstructure than the fish-scale structure, with a rougher surface and specific groove morphology. This structure makes it difficult for liquid to adhere to the surface, tending to form droplets and roll, thus exhibiting low adhesion. In short, different processing conditions shape different microstructures, leading to the difference between high and low adhesion. The fish-scale and groove structures not only contribute to achieving superhydrophobic properties, but the different processing conditions are primarily to meet the specific requirements of achieving low adhesion for the groove structure and high adhesion for the fish-scale structure.
[0058] 1. Distribution patterns and elemental uniformity analysis of Ag clusters in gully structures
[0059] Figure 3 (a) shows an optical image of a heated SERS substrate, from which it can be observed that the substrate is fully heated during the heating process and the surface temperature distribution is uniform. Figure 3 (b) is a thermal image of the heated substrate, further confirming the uniformity of temperature distribution in the heated area, indicating that heat can be uniformly transferred to the entire substrate surface during the heating process. Furthermore, it was also through... Figure 3(c) shows an optical thermal image of the heated SERS substrate, which, combined with optical and thermal imaging techniques, visually presents the temperature distribution of the substrate during the heating process. The results indicate that the heated area of the substrate is uniform during the heating process, with no obvious local overheating or temperature unevenness, which provides a reliable guarantee for stable heating in subsequent experiments.
[0060] from Figure 3 As shown in (c), the temperature of the four test areas (fish-scale structure) is lower than that of the superhydrophobic low-adhesion area (groove structure). This phenomenon can be attributed to the difference in laser marking speed: the laser marking speed in the test areas is faster, resulting in less material being etched and a thicker material. The thicker material may affect the heat transfer efficiency, leading to less heat accumulation on the surface and thus a lower temperature. In contrast, in the superhydrophobic low-adhesion area, the laser marking speed is slower, resulting in more material being etched, making the material thickness in these areas relatively smaller and thus a higher temperature. This finding indicates that the laser marking speed not only affects the morphology of the material surface but also influences heat transfer behavior by changing the material thickness, providing an important basis for optimizing laser processing parameters to achieve a more uniform temperature distribution.
[0061] Detailed analysis of the surface structure of the SERS substrate revealed a regular distribution of Ag clusters. For example... Figure 4 As shown in (a), larger Ag clusters were observed at the junction of the two trenches (the area marked by the orange circle). This is likely because, during the fabrication process, Ag particles may preferentially deposit at the junction of the trenches. Due to the geometric features of these areas (such as edges or corners), Ag particles may more easily accumulate and form larger clusters. In contrast, in the flat areas of the SERS substrate (such as...),... Figure 4 (a) The area marked with a pink circle) shows that the size of the Ag clusters is significantly smaller than that at the gully junction (e.g. Figure 4 (a) The area marked with an orange circle. This size difference is likely closely related to the surface properties of the smooth areas and their influence on the Ag particle stacking behavior. Compared to the trench boundaries, the smooth areas lack obvious geometric undulations (such as edges or corners), which makes the Ag particle stacking behavior more uniform. Without the guidance of trench structures, Ag particles are less likely to aggregate into large clusters in local areas. Although this study did not directly detect the surface-enhanced Raman scattering enhancement effect of Ag clusters of different sizes (large and small clusters), detailed analysis of the substrate surface morphology revealed the distribution patterns of Ag clusters at trench boundaries and in the smooth areas.
[0062] Although the binding modes of silver particles differ, they have little impact on the overall wettability of the SERS substrate. The trench region retains its superhydrophobic and low-adhesion characteristics after coating. This may be because, with sufficient roughness, the silver film thickness is relatively thin, and the wettability of the silver particles themselves has little effect on the wettability of the SERS substrate. Elemental mapping analysis (e.g., ...) was performed on SERS substrates modified with PFTS and silver-plated by magnetron sputtering. Figure 4 As shown in (b, c, d), fluorine (F), silicon (Si), oxygen (O), carbon (C), and silver (Ag) elements were found to be uniformly distributed on the substrate surface. The uniform distribution of F, Si, O, and C elements confirmed that PFTS modification was applied to the substrate surface and formed a stable chemically bonded layer, while the uniform distribution of Ag elements indicated that the magnetron sputtering silver plating process achieved uniform deposition of Ag particles.
[0063] 2. Design of SERS substrate based on fish scale structure and wettability of the substrate
[0064] Figure 5 (a) Demonstrates a fish-scale-like structure ingeniously fabricated using nanosecond laser technology. This structure not only possesses a unique surface morphology but also exhibits surface-enhanced Raman scattering properties, such as... Figure 6 As shown in (de), the achievable detection limit is 10. -16 M. By plating silver onto the fish-scale-like structure, the SERS enhancement effect was further achieved. The uniform deposition of silver particles on the fish-scale-like structure formed abundant "hot spot" areas, such as... Figure 5 (e) As shown in the elemental mapping of Ag, these regions can enhance the local electromagnetic field, thereby significantly increasing the intensity of the Raman signal. This biomimetic design combined with silver plating provides a new approach to developing high-performance SERS substrates, demonstrating their enormous application potential in sensing and biosensing. To verify the substrate's adhesion during detection, contact angles were measured at tilt angles of 0°, 45°, 90°, and 180°. Figure 5 As shown in (b), it was found that even when completely flipped, good adhesion was maintained, which would ensure that the test liquid was positioned during the drying process without slipping.
[0065] according to Figure 5 (c) EDX analysis revealed that the oxygen content in the fish-scale structure region was lower than that in the groove structure region. Figure 4 (b) This phenomenon can be explained from the perspective of laser ablation: during nanosecond laser processing, the laser energy density and rate have a significant impact on the oxidation behavior of the material surface (the only difference between groove structures and fish-scale structures is the marking rate, such as...). Figure 2(As shown). The formation of fish-scale structures typically requires a high laser marking rate, which leads to rapid ablation and resolidification of the material surface within a very short time, thereby reducing oxidation. In contrast, the formation of trench structures may involve a slower laser marking rate, making the material surface more susceptible to reaction with oxygen from the surrounding environment during laser treatment, resulting in a higher oxygen content. Therefore, the energy density and ablation rate during laser ablation are key factors affecting the degree of surface oxidation, leading to lower oxygen content in fish-scale structures compared to trench structures. This finding provides a new perspective for optimizing laser processing parameters to reduce oxidation. Simultaneously, to detect the uniformity of individual elements, overall and layered mappings of each element were performed, as shown... Figure 5 As shown in (d) and (e), it can be seen that the elements are evenly distributed on the substrate surface.
[0066] Figure 6 (a) illustrates the drying of analyte molecules at the fish-scale structure during the evaporation enrichment process. Due to the unique surface properties of the fish-scale structure (high adhesion) and the superhydrophobic surface properties of the groove structure, liquids more easily form local evaporation enrichment points in the fish-scale structure region, leading to the drying and concentration of analyte molecules at the fish-scale structure. This selective enrichment behavior not only enhances the local intensity of the surface-enhanced Raman scattering signal but also improves the detection sensitivity. Figure 6 (b) shows the drying and enrichment process of 5 μL of liquid heated to 70 °C, with continuous images from 0 to 56 seconds recording the rapid evaporation behavior of the liquid under heating conditions. In contrast, Figure 6 (c) illustrates the evaporation enrichment process without heating. Continuous images from 0 to 36 minutes show the slow evaporation behavior of the liquid at room temperature. By comparing the evaporation process under heating and non-heating conditions, it is clearly observed that heating accelerates the evaporation of the liquid and the enrichment of the solute, providing an important reference for improving the efficiency and sensitivity of SERS detection.
[0067] Figure 6 (d) and Figure 6 (e) Results of surface-enhanced Raman scattering (SERS) detection using Rhodamine 6G as a probe molecule are presented. The detection limit of the prepared SERS substrate was evaluated by detecting R6G at different concentrations. The rapidly concentrated SERS substrate exhibited extremely high sensitivity, capable of detecting concentrations as low as 10⁻⁶. -16 M R6G solution. Figures 5-7 The image shows the Raman spectra of R6G solutions at different concentrations, from 10... -9 M to extremely low concentrations of 10 -16 M. As the R6G concentration decreases, the intensity of the Raman signal gradually weakens, but at 10 -16Characteristic peaks could still be clearly detected at M, indicating that the prepared heated rapidly concentrated SERS substrate exhibited excellent detection performance. This result confirms the application potential of the developed SERS substrate in ultra-high sensitivity detection and provides strong technical support for trace analysis.
[0068] Figure 7 This paper presents a heated SERS substrate with nine test sites designed on a 12×12 mm² copper substrate, along with its optical images. The thermal image and optical photographs clearly demonstrate excellent heating uniformity across the nine test areas during the heating process. This design not only maximizes the use of the substrate area and reduces material waste but also ensures consistency and reliability of each test site during the experiment. The uniform heating distribution facilitates the simultaneous detection of multiple samples, improving experimental efficiency and data reproducibility. This multi-region heating design offers advantages in practical applications. It allows researchers to simultaneously detect multiple samples on the same substrate, significantly reducing experimental time and increasing efficiency. Because the heating conditions in each region are highly consistent, the reliability and comparability of the experimental results are effectively guaranteed. Furthermore, this design enables high-throughput detection, making it particularly suitable for scenarios requiring rapid screening of large numbers of samples, such as drug screening or environmental pollutant monitoring.
[0069] This embodiment systematically studies the preparation process, surface properties, and performance optimization of a heated SERS-enriched substrate. Experimental verification shows that this substrate accelerates the liquid evaporation enrichment process under heating conditions, solving the problem of slow drying speed on traditional superhydrophobic or superhydrophobic-superhydrophilic surfaces. Combining a biomimetic fish-scale structure and groove design, the substrate surface exhibits unique wettability regulation capabilities, providing an ideal platform for efficient analyte enrichment. Elemental analysis and morphological characterization results show that silver nanoparticles are uniformly distributed on the substrate surface, and abundant "hot spot" regions are formed at the groove boundaries, providing a structural basis for SERS signal enhancement. Performance testing further confirms that the detection limit of this substrate can reach 10-1. -16 M demonstrates its great potential in trace detection.
[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A highly sensitive wettability heating SERS substrate based on a fish-scale-like structure, characterized in that, The system includes an assembled SERS substrate and a heating substrate. The SERS substrate is based on a copper substrate with a fish-scale-like structure and a trench structure surrounding the detection areas on its surface. The surface of the copper substrate is sequentially covered with a 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFTS) modified layer and a silver film. The heating substrate is based on a glass slide with a silver nanowire layer on its surface, which is covered with non-conductive double-sided adhesive tape. The SERS substrate is bonded and fixed to the heating substrate by the double-sided adhesive tape.
2. The highly sensitive wettability heating SERS substrate based on a fish-scale-like structure according to claim 1, characterized in that, The silver nanowire layer consists of silver nanowires with a diameter of 20-100 nm, a length of 10-20 μm, and a thickness of 3-5 μm, and the silver nanowires form a continuous conductive network on the surface of the glass sheet.
3. The highly sensitive wettability heating SERS substrate based on a fish-scale-like structure according to claim 1, characterized in that, The fish-scale-like structure has superhydrophobic and high adhesion properties (a 5μL droplet still adheres when tilted 180° on a copper substrate), while the trench structure has superhydrophobic and low adhesion properties. The surface contact angle between the two regions is ≥150°, and the oxygen content in the fish-scale structure region is lower than that in the trench structure region.
4. The highly sensitive wettability heating SERS substrate based on a fish-scale-like structure according to claim 1, characterized in that, The surface of the silver film is covered with silver nanoclusters: large clusters with a diameter of 200-300 nm are located at the junction of the groove structure, and small clusters with a diameter of 50-100 nm are located in the flat area of the fish scale structure.
5. The highly sensitive wettability heating SERS substrate based on a fish-scale-like structure according to claim 1, characterized in that, The non-conductive double-sided tape has a thickness of 0.08-0.18mm, is made of medical-grade insulating material, and has a peel strength ≥2N / cm.
6. A method for preparing a highly sensitive wettability heated SERS substrate based on a fish-scale-like structure, characterized in that, Includes the following steps: S1. Preparation of SERS substrate: A fish-scale structure and a trench structure were fabricated on a copper substrate using a 355nm ultraviolet nanosecond laser. After being soaked in a PFTS mixture and dried to form a modified layer, a 50-100nm thick silver film was sputtered by magnetron sputtering. S2. Preparation of heating substrate: Spin-coat a mixture of 0.1-1.0 mg / mL silver nanowires and 5-20 mg / mL silver isopropoxide nanowires onto the surface of a glass slide 4-10 times to form a silver nanowire layer, and cover it with non-conductive double-sided adhesive tape; S3. Assembly: Attach the SERS substrate to the double-sided adhesive tape of the heated substrate to obtain the target substrate.
7. The method for preparing a highly sensitive wettability heated SERS substrate based on a fish-scale-like structure according to claim 6, characterized in that, The parameters for preparing the fish-scale-like structure in step S1 are: laser power 3-5W, scanning rate 200-400mm / s, number of scans 4-6, and processing spacing 0.03-0.07mm; the parameters for preparing the groove structure are: laser power 4-6W, scanning rate 30-70mm / s, number of scans 5-8, and processing spacing 0.04-0.08mm.
8. The method for preparing a highly sensitive wettability heated SERS substrate based on a fish-scale-like structure according to claim 6, characterized in that, In step S2, the glass slide needs to be pretreated before spin coating: soak it in a mixture of hydrogen peroxide and concentrated sulfuric acid (volume ratio 1:3) for 20-60 minutes, rinse it with deionized water, and then blow it dry with nitrogen.
9. An application method for a highly sensitive wettability heated SERS substrate based on a fish-scale-like structure, characterized in that, For trace SERS detection, the following steps are included: A. Add 5 μL of the test liquid to the fish scale-like detection area of the substrate according to any one of claims 1-5; B. Apply a DC voltage to the silver nanowire layer to raise the temperature of the detection area to 50-100℃, thereby accelerating the evaporation and enrichment of the liquid. C. Detection using a Raman spectrometer, with a detection limit of not less than 10. -16 M.
10. The application method of the highly sensitive wettability heating SERS substrate based on a fish-scale-like structure according to claim 9, characterized in that, In step B, the DC voltage is 8-15V, and the time from the addition of the liquid to complete evaporation is ≤1 minute.