Vertically aligned silicon nanowires with indium tin oxide thin film coating and their applications in sensitive nanoelectronic devices

Abstract

The present application relates to a nanostructure sensing substrate, which comprises vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide (ITO) coating. The ITO / USNWs are prepared by first producing vertically aligned silicon nanowires (USNWs) through a silver metal-assisted chemical etching method, then reducing the density of the USNWs through KOH / IPA, and finally coating the ITO coating. In addition, the ITO / USNWs modified by biological receptors can be developed as a sensing substrate, and other electronic reading devices can be connected to read the voltage, current or resistance signals, so as to realize the label-free detection of diseases related to biological markers, such as acute myocardial infarction, coronary artery disease, and cancer. In addition, the vertically aligned silicon nanowires coated with the ITO coating can also be used in cell biological sensors to quantitatively evaluate the electrical properties of cells affected by drug release.

Description

Technical Field

[0001] This invention relates to a sensitive nanoelectronic device (NED), primarily a nanostructure sensing substrate comprising vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide film coated upstanding silicon nanowires. Background Technology

[0002] Extended gate field-effect transistors have been widely developed to address problems encountered when using transistors for biosensing, such as damage to conventional transistors caused by ions from biomolecules, salts, and electrolytes.

[0003] Various structures and materials have been applied to sensing substrates for extended gate field-effect transistors, such as gallium nitride nanowires (GaN NWs), zinc oxide nanowires (ZnO NWs), coaxial zinc oxide / silicon nanowires (ZnO / SiNWs), copper oxide nanowires (CuO NWs), zinc oxide / tantalum (ZnO / Ta) films, palladium oxide (PdO) films, indium zinc oxide (InZnxOymembrane) films, zinc oxide nanoarrays (ZnO nano-arrays), indium nitride / indium gallium nitride quantum dots (InN / InGaN quantum dot), and indium tin oxide (ITO) films (Ahmed, NM, et al., Semicond Sci Tech 36(4), 2021). Among the various available nanostructures, upstanding nanowires (USNWs) are particularly noteworthy due to their ability to interact extensively with the nanoscale features of biomolecules. It is worth noting that surface modification and functionalization of sensing substrates with high aspect ratios can improve the sensing sensitivity and specificity of EGFETs, thereby expanding the application of EGFETs to the detection of a variety of biological substances. Summary of the Invention

[0004] The purpose of this invention is to provide a nanostructure sensing substrate comprising vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide coating. The nano-roughened surface of the vertically aligned silicon nanowires with the modified indium tin oxide coating can serve as a sensing substrate, or it can be externally connected to other electronic readout devices to read signals such as voltage, current, or resistance, and can be applied to label-free and specific detection of biomarkers for certain diseases.

[0005] To achieve the above objectives, the present invention provides a nanostructure sensing substrate comprising vertically aligned silicon nanowires with an indium tin oxide (ITO) coating, wherein the average height of the vertically aligned silicon nanowires is 0.01-10 μm, and the thickness of the ITO coating is 10-600 nm. According to one embodiment of the present invention, the average height of the vertically aligned silicon nanowires is 0.01-4 μm, and the thickness of the ITO film is 100-400 nm.

[0006] In some embodiments of the invention, the vertically aligned silicon nanowires with an indium tin oxide coating comprise a nanoroughened surface having a suitable average surface roughness greater than 400 nm. According to one embodiment of the invention, the average surface roughness of the nanoroughened surface ranges from 50 to 1000 nm. According to another embodiment of the invention, the average surface roughness of the nanoroughened surface ranges from 400 to 650 nm.

[0007] In some embodiments of the invention, the vertically aligned silicon nanowires with an indium tin oxide coating are further coated on their nano-roughened surface with small molecules containing silanol groups, such as 3-aminopropyltrimethoxysilane, to further bond to cells, proteins, or biological receptors. In other embodiments of the invention, the biological receptor includes, but is not limited to, biomarked antibodies. In one embodiment of the invention, the biological receptor is a cardiac troponin I antibody.

[0008] In another aspect, the present invention provides a method for preparing the above-mentioned vertically aligned silicon nanowires with an indium tin oxide (ITO) coating, comprising the following steps: forming silver nanoparticles on a silicon surface; performing silver-assisted chemical etching in a solution of hydrofluoric acid and hydrogen peroxide for 0.5-4 minutes to produce vertically aligned silicon nanowires with a high aspect ratio and a nano-rough surface; reducing the density of the vertically aligned silicon nanowires using a potassium hydroxide / isopropanol solution; and coating the vertically aligned silicon nanowires with an ITO layer to prepare vertically aligned silicon nanowires with an ITO coating. The ITO / USNWs can be used as a sensing substrate for extended gate field-effect transistor (FET) devices.

[0009] In some embodiments of the invention, the silver-assisted chemical etching described by USNWs is performed in the dark for 3-4 minutes. In some embodiments of the invention, the density reduction step is performed in an aqueous solution containing 4.0-4.45M potassium hydroxide and 0.8-2.61M isopropanol for 5 seconds to 2 minutes, for example, for 20-30 seconds.

[0010] In some embodiments of the present invention, the method for preparing vertically aligned silicon nanowires with an indium tin oxide coating further includes the steps of modifying the surface of the vertically aligned silicon nanowires with an indium tin oxide coating using 3-aminopropyltrimethoxysilane and subsequently binding them to a protein.

[0011] In another aspect, the present invention provides a method for the immediate detection of acute myocardial infarction, comprising detecting human cardiac troponin I from a liquid biopsy of a subject using a nanostructured sensing substrate comprising vertically aligned silicon nanowires with an indium tin oxide coating. In some embodiments of the invention, the nanoroughened surface of the vertically aligned silicon nanowires with an indium tin oxide coating is modified with 3-aminopropyltrimethoxysilane and a cardiac troponin I antibody to form cardiac troponin I antibody-modified vertically aligned silicon nanowires with an indium tin oxide coating. In one embodiment of the invention, the nanostructured sensing substrate is integrated into the impedance measurement system of a sensitive nanoelectronic device and used as a working electrode. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a method for manufacturing a nano-rough surface of a sensing substrate according to an embodiment of the present invention.

[0013] Figures 2A to 2C The morphology of the nano-roughened surface of the sensing substrate, observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), is shown; among them, Figure 2A SEM image of vertically aligned silicon nanowires (USNWs) after silver-assisted chemical etching (MACE); Figure 2B SEM images of USNWs after density reduction; Figure 2C AFM image of vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide coating; Figure 2B and Figure 2C The magnification is 1000K X.

[0014] Figures 3A to 3D The reactions of extended gate field-effect transistors (GFETs) with indium tin oxide coatings and modified with 3-aminopropyltrimethoxysilane (APTMS) as vertically aligned silicon nanowires (APTMS / ITO / USNWs) in solutions of different pH values ​​(pH = 3-11) are demonstrated; among which, Figure 3AThe relationship between current and gate voltage (I) in buffer solutions of different pH values ​​is shown. D -V G The transfer characteristics of ). Figure 3B The threshold voltage (V) in the solution is shown. T,sol The linear relationship between pH value and pH value; Figure 3C The output characteristics in the saturation region of different pH buffer solutions were shown (I D -V D ); Figure 3D This shows the square root of the current (I) in the saturation region. D ) 1 / 2 Linear relationship with pH value.

[0015] Figures 4A to 4D The following results are presented; among them, Figure 4A The resistance result is the impedance spectrum; Figure 4B The reactance result is for the impedance spectrum; Figure 4C Calibration curves for different concentrations of cardiac troponin I (cTnI) are shown. Error bars represent the mean ± standard error (SEM, n=6). Figure 4D The selectivity of cTnIAb-modified vertically aligned silicon nanowires with an indium tin oxide coating (cTnIAb-modified ITO / USNWs) was demonstrated using bovine serum albumin (BSA).

[0016] Figure 5A An example of a nanoscale cell-based biosensor (CBB) is shown for use in non-Latin electrochemical impedance spectroscopy (EIS) measurements.

[0017] Figure 5B Significant changes in electrical signals in electrochemical impedance spectroscopy were observed during cell culture and drug (125 μg / mL curcumin) treatment. Detailed Implementation

[0018] This invention provides a nanostructured sensing substrate comprising vertically aligned silicon nanowires (referred to as ITO / USNWs) with an indium tin oxide coating. Using silver nanoparticles as a catalyst, silver metal-assisted chemical etching is employed in an HF / H2O2 / H2O solution to etch the silicon substrate to form the vertically aligned silicon nanowires (USNWs). Then, the USNWs are further etched in a KOH / IPA solution to form USNWs of appropriate density. Next, an ITO film is deposited on the vertically aligned silicon nanowires as a sensing conductive layer. Subsequently, the surface of the ITO-coated USNWs is modified with a self-assembled monolayer (SAM) of (3-aminopropyl)trimethoxysilane (APTMS) to immobilize a bioreceptor, such as cardiac troponin I antibody. Antibody (cTnIAb), neurofilament light chain antibody (NFLAb), and L-lactate dehydrogenase (LDH).

[0019] Other features and advantages of the present invention will be further illustrated and described in the following embodiments. The embodiments described in this document are for illustrative purposes only and do not constitute a limitation thereof.

[0020] Example 1: Fabrication of vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide coating

[0021] Figure 1 This is a schematic diagram illustrating a method for manufacturing a nano-roughened surface of a sensing substrate according to an embodiment of the present invention, for further attachment to the gate of a metal oxide semiconductor field-effect transistor (MOSFET). Silver nanoparticles are used as a catalyst in an HF / H₂O₂ / H₂O solution, and a silver-assisted chemical etching method is used to etch a silicon substrate to form the vertically aligned silicon nanowires (USNWs). After reducing the density of the USNWs using a KOH / IPA solution, ITO is coated onto the USNWs to form ITO / USNWs, which serve as the sensing substrate for an extended gate MOSFET device. The preparation method is described below.

[0022] First, a nano-roughened surface with a high aspect ratio, USNWs, was prepared using a simple metal-assisted chemical etching method. Silicon wafers were sequentially ultrasonically cleaned in ultrapure water, acetone, and 95% ethanol, and then dried using nitrogen. To prevent etching of the unpolished back side of the silicon wafer, it was spin-coated with AZ1518 photoresist at 2,000 rpm for 30 seconds, and then baked on a hot plate at 100°C for 1.5 minutes. The wafer was then immersed in 20 mL of 3% HF solution for 3 minutes to remove the native oxide layer on the surface. Next, the wafer was immediately immersed in an aqueous solution containing 0.005 M AgNO3 and 4.8 M HF for 4 minutes for electroless deposition of silver nanoparticles (AgNPs) in the dark. After being gently rinsed with ultrapure water, the silicon wafer was immersed in an etching solution containing 8.61 M HF, 0.45 M H2O2 and 48 M H2O and etched in the dark for 3 minutes to generate vertically aligned silicon nanowires (USNWs).

[0023] After the formation of USNWs, they were first thoroughly rinsed with ultrapure water. Then, the sample was immersed in 20 mL of a 1:1 (v / v) HNO3 aqueous solution for 10 minutes to remove the AgNP catalyst. After thorough rinsing with ultrapure water, the silicon sample was immersed in 20 mL of a 5% HF solution for 3 minutes to remove the oxide layer, and then rinsed again with water. Finally, the photoresist coating on the back of the silicon sample was dissolved using acetone, rinsed with 95% ethanol, and then dried on a hot plate at 110°C. To reduce the areal density of the USNWs to facilitate uniform ITO coating in the next step, the USNWs were further immersed in a 20 mL aqueous solution containing 4.45 M KOH and 2.61 M isopropanol (IPA) for 20 seconds for etching. The etched sample was rinsed with 95% ethanol and dried on a hot plate at 110°C.

[0024] Uniform coating of the ITO thin film was performed using an ion-assisted electron beam evaporation system (SGC-22SA; Showa Vacuum Corporation, Japan), with O2 (10 sccm) as the reactant gas and Ar (12 sccm) as the working gas. Before evaporation, the chamber was evacuated to an internal pressure of 2 × 10⁻⁶. -3 Pa, the pressure is maintained at 5×10 during the vapor deposition process. -2 Pa. The anode voltage and filament current were set to 130V and 2.3A, respectively, and the deposition rate was [missing value]. The same process parameters were also used to prepare planar ITO films on glass slides. The thickness of the deposited ITO film (approximately 400 ± 50 nm) was measured using a probe profilometer (Dektak; Bruker, Massachusetts, USA). After ITO coating, the samples were annealed in an oven at 500°C for 1 hour to form a denser and more conductive ITO film. Subsequently, the ITO / USNWs were cut into 1.1 × 1.3 cm pieces. 2 It is a sheet-like material used as a sensing substrate for extended gate field-effect transistor (EGFET) devices.

[0025] The surface morphology of the sensing substrate was examined using field-emission scanning electron microscopy (FE-SEM; ZEISS Ultra Plus; Zeiss, Germany) and atomic force microscopy (AFM; DI-3100; Veeco, New York, USA). SEM images were obtained using the InLens mode of the FE-SEM at an accelerating voltage of 10 kV. AFM measurements were performed in soft-tapping mode with a scanning range of 10 × 10 μm. 2 (Including glass, USNWs, ITO / USNWs, and APTMS / ITO / USNWs), the scan rate was 0.598 Hz. Each scan contained 256 lines, with 512 samples per line. AFM data were visualized and analyzed using NanoScope Analysis software (version 1.70; Bruker, MA, USA) to determine the average surface roughness (Ra).

[0026] After 20 seconds of etching, the nano-roughened surface of the USNWs was formed, with a significantly increased average surface roughness (Ra) (657.33 ± 46.10 nm). In contrast, the Ra of the ITO film was 2.07 ± 0.62 nm, while the Ra of the USNWs after the MACE process was 123.33 ± 17.12 nm. Although the Ra of ITO / USNWs decreased (568.17 ± 46.48 nm), it still retained the appropriate roughness of a nano-roughened surface. The difference in Ra between USNWs and ITO / USNWs was not significant, indicating that the ITO film was uniformly deposited on the nano-roughened surface of the USNWs.

[0027] SEM images of USNWs fabricated on a silicon substrate using the MACE process show that the USNWs are uniformly and vertically aligned on the substrate surface, with a height of approximately 2.8 μm and a high aspect ratio. Figure 2AAfter 20 seconds of KOH / IPA etching, the density and height of USNWs decreased significantly, with the height reduced to 2.3 μm. Figure 2B After depositing a 400 nm thick ITO film on USNWs, the height of the ITO / USNWs increased to approximately 2.8 μm. Figure 2C The results show that USNWs nanostructure sensing substrates with controllable areal density can be successfully fabricated by MACE and KOH / IPA etching. The nano-rough surface is suitable for uniform ITO coating and subsequent surface modification.

[0028] To quantify the performance of the fabricated APTMS / ITO / USNWs extended gate field-effect transistor (EGFET) for future application in sensing neuron-derived exosomes, its transfer characteristics in the linear region (IL) were collected. D -V G (curve) and output characteristics in the saturation region (I) D -V D (Curve). The experiment used solutions with different pH values ​​(pH = 3-11) for testing, and the results are as follows. Figures 3A to 3D As shown. According to MOSFET theory, I D The reactions in the linear and saturated regions can be expressed by equations (1) and (2), respectively:

[0029]

[0030] Where, μ n C represents the carrier mobility of the channel. ox V represents the gate oxide capacitance per unit area, where W and L represent the width and length of the channel, respectively. G V T and V D These represent the reference electrode voltage (V) REF ), threshold voltage, and drain-source voltage of the EGFET sensor.

[0031] When an EGFET sensor is immersed in an electrolyte solution, the threshold voltage V changes due to the shift in surface potential at the interface between the functionalized sensing surface (such as an antibody or chemical functional group) and the electrolyte solution. T Significant changes will occur. Therefore, the threshold voltage (V) in the solution... T,sol The signal of our APTMS / ITO / USNWsEGFET can be represented by formula (3) for further analysis:

[0032]

[0033] Among them, E ref The reference electrode potential is equivalent to V. REF; Φ0 is the surface potential at the interface between the functionalized surface of the sensing substrate and the electrolyte solution; χ sol The surface potential of the buffer solution; Let V be the work function of the conductive reference electrode. At a fixed V... D Under the condition that V = 0.3V, let V G The IT of APTMS / ITO / USNWs EGFET is measured by scanning within the 0-3V range. D -V G curve.

[0034] like Figure 3A As shown, with the increase of pH value, i.e. H + As the concentration decreases from high to low, the concentration of OH- increases, and V... T,sol Moving from left to right. This indicates that negative charges are attracted to the APTMS-modified sensing surface, and negatively charged ions (OH-) repel electrons in the n-channel, thereby reducing the current I. D .according to Figure 3B Chinese V T,sol The relationship curve between pH value and the prepared APTMS / ITO / USNWs EGFET device shows that it has high sensitivity to changes in pH value, with a reaction sensitivity of 47.27 mV / pH and a linearity of 0.99 in the pH range of 3 to 11.

[0035] Figure 3C The APTMS / ITO / USNWs EGFET in the saturation region is shown. D -V D Curve, through a fixed V G Under the condition of 1.5V, V D The values ​​were measured from 0V to 3V in solutions with different pH values ​​(pH = 3-11). According to formula (2), the current (I) can be analyzed... D ) 1 / 2 To evaluate the device's response to pH changes. Current I in the n-channel. D The reduction is attributed to the presence of hydroxyl anions in the alkaline solution. For example... Figure 3D As shown, (I) D ) 1 / 2 The pH-dependent curve confirms that the APTMS / ITO / USNWs EGFET exhibits excellent pH sensitivity of 0.77 μA. 1 / 2 The linearity is 0.96 at pH / . Based on the electrical properties of the aforementioned nanostructure sensing substrate, it can be seen that vertically aligned nanostructures can significantly improve sensing sensitivity and stability.

[0036] Example 2: Detection of cardiac troponin I using a sensitive nanoelectronic device comprising vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide coating.

[0037] Currently, cardiac troponin I (cTnI) and cardiac troponin T (cTnT) biomarkers are considered the gold standard for diagnosing acute myocardial infarction (AMI) due to their high sensitivity. In this embodiment, a sensitive nanoelectronic device prepared in Example 1 is used, comprising vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide coating, for detecting cTnI in human serum. The ITO-coated USNWs have a length of 2.5 μm. Energy-dispersive X-ray spectroscopy (EDX) analysis shows that indium accounts for 16.07% of the atomic content of ITO. After modification with a cardiac troponin I antibody (cTnIAb), the cTnIAb-modified ITO-coated USNWs are used to detect different concentrations of cTnI in human serum via a microfluidic system.

[0038] Polydimethylsiloxane (PDMS) microfluidic channels (16 mm × 1 mm × 0.06 mm) were fabricated using standard microfabrication techniques to deliver the sensing substance. The PDMS microfluidic channels were then assembled on top of the exposed sensing area of ​​the nanoelectronic device (NED), and a syringe pump was used to flow the sample liquid through the analytical area. A silver / silver chloride (Ag / AgCl) reference electrode (ALS, RE-1S) was used as the counter electrode for ground potential. Clinical trials using different concentrations of cTnI in patient serum have been approved by the Ethics Committee of Changhua Christian Hospital (IRB No. 170113). Human serum diluted 10-fold with known concentrations of cTnI was used for detection to validate sensing performance. Impedance measurements were performed using an E4980A high-precision LCR instrument (Agilent Technologies) in frequency scan mode, operating at 2 mV over a frequency range of 20 Hz to 2 MHz. Analytical results are expressed as impedance components (resistance and reactance), and statistical significance was assessed using independent t-tests. Sensing selectivity was validated using bovine serum albumin (BSA, 66.5 kDa).

[0039] like Figure 4A As shown, the change in resistance is proportional to the increase in cTnI concentration. Due to the capacitive effect of cTnI on the cTnIAb-modified ITO coating USNWs, the reactance shifts at higher frequencies. Figure 4A and 4BThis demonstrates the direct correlation between charged cTnI and the interfacial interaction between it and the sensing surface. Figure 4C The calibration results for resistance changes at different cTnI concentrations are shown, and a regression equation (y = 0.40819x + 0.18075) is obtained in the range of 1.76011–17601.1 ng / mL. Based on the results, the limit of detection (LOD) of cTnI is calculated to be 0.53 ng / mL (R0). 2 =0.96). and Figure 4A and 4B In comparison, when detecting bovine serum albumin (BSA, 66500.0 ng / mL), the electrical resistance ( Figure 4D ) and reactance ( Figure 4D No significant changes were observed in the embedded images, indicating better sensing selectivity. Based on impedance measurements for cTnI detection, we summarized the sensing characteristics using two articles on different nanomaterials (see Table 1) to demonstrate the feasibility of this invention. The results show that the cTnIAb-modified ITO / USNWs in this invention exhibit comparable sensing results in cTnI detection.

[0040] Table 1: Comparison of different nanomaterials in cTnI detection

[0041]

[0042] Example 3: Electrophysiological quantitative assessment of drug release using vertically aligned silicon nanowires (ITO / USNWs) with indium tin oxide coating in a cell biosensor (CBB).

[0043] A nanoscale cell-based biosensor (CBB) such as Figure 5A As shown. Vertically aligned silicon nanowires (ITO / USNWs) with an indium tin oxide coating were prepared according to the method of Example 1. After modification with 3-aminopropyltrimethoxysilane, a polystyrene cylinder with a PDMS cap was mounted on top of the device. MCF7 cells (human breast adenocarcinoma, ATCC HTB-22) were induced at 2.9 × 10⁻⁶ cells / year. 4 cells / cm 2 The density was measured and cultured in DMEM containing 10% fetal bovine serum (FBS) at 37°C and 5% CO2. For drug treatment, 125 μg / mL curcumin-encapsulated nanocarriers were added to nano-sized CBBs for testing.

[0044] In this embodiment, a Keysight E4980A high-precision LCR instrument was used. The E4980A, operating at 1mV, recorded the relationship between reactance and resistance at 100 sampling points within a frequency range of 20Hz to 2MHz to observe the survival and death of MCF-7 cells. Figure 5B As shown, the nanoscale cell biosensor of the present invention exhibits high stability and repeatability in various sensing environments. On days 1, 2, and 3 of cell culture, the nanoscale CBB showed significant changes in impedance spectra. Signal disturbances were observed after processing the curcumin-encapsulated nanocarrier.

[0045] In addition to neuroimaging recommended by most clinical guidelines, embodiments of this invention demonstrate that the developed nano-roughened surface, utilizing a modified nanostructured sensing substrate, can also be combined with EGFET to detect NFL (neurofilament light chain) specific neuronal-derived exosomes (NDEs), with a limit of detection (LOD) of 60 NDEs / mL and a limit of quantitation (LOQ) of 6 × 10⁻⁶. 3 NDE / mL. The correlation between the level of NFL-specific NDEs in plasma and the severity of cognitive impairment can be achieved through label-free and rapid differentiation using NFLab / APTMS / ITO / USNWs EGFETs, with a detection time of only 2 minutes. Furthermore, the captured NFL-specific NDEs can be further washed, desorbed, and processed from the modified EGFET nano-roughened surface for future extraction of important proteins associated with cognitive brain disorders.

[0046] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A nanostructured sensing substrate, characterized in that, Include: Vertically aligned silicon nanowires with an indium tin oxide coating, wherein the average height of the vertically aligned silicon nanowires is 0.01-10 μm and the thickness of the indium tin oxide coating is 10-600 nm.

2. The nanostructure sensing substrate according to claim 1, characterized in that, The vertically aligned silicon nanowires with an indium tin oxide coating contain a nano-rough surface with an average surface roughness of 50-1000 nm.

3. The nanostructure sensing substrate according to claim 2, characterized in that, The average surface roughness of this nano-rough surface is 400-650 nm.

4. The nanostructure sensing substrate according to claim 1, characterized in that, The nano-roughened surface of the vertically aligned silicon nanowires with an indium tin oxide coating is further modified with small molecules containing silanol groups to further bond to cells, proteins, or biological receptors.

5. The nanostructure sensing substrate according to claim 4, characterized in that, The small molecule containing silanol groups is 3-aminopropyltrimethoxysilane.

6. The nanostructure sensing substrate according to claim 4, characterized in that, The biological receptor is an antibody.

7. The nanostructure sensing substrate according to claim 6, characterized in that, The biological receptor is a cardiac troponin I antibody.

8. A method for fabricating a nanostructure sensing substrate according to claim 1, characterized in that, Includes the following steps: Silver nanoparticles are formed on the silicon surface; Silver-assisted chemical etching was performed in a solution of hydrofluoric acid and hydrogen peroxide for 0.5 to 4 minutes to produce the vertically aligned silicon nanowires with a high aspect ratio nano-rough surface. The density of the vertically aligned silicon nanowires was reduced using a potassium hydroxide / isopropanol solution. as well as An indium tin oxide thin film is coated on the vertically aligned silicon nanowires of the nanostructure sensing substrate.

9. The method for preparing a nanostructured sensing substrate according to claim 8, characterized in that, The silver-assisted chemical etching process is carried out in the dark for 3 to 4 minutes.

10. The method for fabricating a nanostructured sensing substrate according to claim 8, characterized in that, The density reduction step is carried out in an aqueous solution containing 4 to 4.45 M potassium hydroxide and 0.8 to 2.61 M isopropanol for 5 seconds to 2 minutes.

11. The method for fabricating a nanostructure sensing substrate according to claim 8, characterized in that, It further includes the step of modifying the surface of the vertically aligned silicon nanowires with an indium tin oxide coating with small molecules containing silanes.

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