Application of self-assembled peptide nano array / ZnO composite gas-sensitive material in acetone gas sensor

Abstract

The invention discloses an application of a self-assembled peptide nano array / ZnO composite gas sensitive material in an acetone gas sensor. The self-assembled peptide nano array with a porous structure is prepared by utilizing a physical vapor deposition technology, ZnO nano particles can be effectively adsorbed and dispersed, adsorption and desorption of acetone gas are facilitated, and transmission of electrons is also facilitated. The prepared sensor exerts the synergistic effect of the self-assembled peptide nano array and ZnO, realizes efficient detection of gas acetone exhaled by a human body at room temperature, has very high selectivity to acetone, has relatively high response to low-concentration acetone, and provides a thought for noninvasive detection of diabetes mellitus.

Description

Technical Field

[0001] This invention belongs to the field of gas sensor technology, specifically relating to an acetone gas sensor based on a self-assembled peptide nanoarray / ZnO composite gas-sensitive material. Background Technology

[0002] With the development of the big health industry and non-invasive medical technology, breath biomarker detection technology, as a non-invasive, painless, and non-surgical new method for disease diagnosis, has seen significant development in health management and disease prevention. For example, acetone, a breath biomarker for diabetic ketoacidosis, has a concentration of 0.3 ppm-0.9 ppm in the breath of healthy individuals, but as high as 1.8 ppm in the breath of patients with ketoacidosis. Accurate detection of acetone concentration in breath can enable early screening, disease monitoring, and early warning of ketoacidosis risk in diabetes. People are increasingly valuing their health. The demand for "self-health monitoring" in home settings is surging. Traditional diabetes testing methods relying on blood draws and professional hospital equipment can no longer meet the needs of "real-time, convenient, and home-based" care. Portable breathalyzer devices, which can directly collect exhaled gases and output test results instantly, have become an ideal choice for home diabetes management. The core function of such devices relies entirely on high-performance acetone gas sensors.

[0003] Currently, metal-oxide-semiconductor (MOS) gas sensors are widely used, but these sensors still have some problems, such as high operating temperature (200-400℃, requiring an additional heating module, making them unsuitable for portable devices), easy particle aggregation, susceptibility to poisoning, poor selectivity (easily affected by interfering gases such as ethanol and methanol in exhaled breath), and insufficient sensitivity at low concentrations (difficult to capture the difference in acetone concentration between healthy individuals and early-stage patients), which cannot meet the needs of non-invasive diabetes detection. Therefore, there is an urgent need to develop gas-sensitive materials with low operating temperature, high sensitivity, and high selectivity, as well as suitable preparation processes to improve gas-sensitive performance. Biomass aromatic short peptide self-assembled nanoarrays are an ideal selective gas-sensitive material for the following reasons: ① They are p-type organic semiconductors, easy to synthesize and modify, and have good biocompatibility; ② The structure of aromatic short peptide self-assembled nanoarrays is tunable, with high temperature stability (~150℃), and the ordered structure is conducive to carrier transport; ③ The large specific surface area of ​​the array structure can provide more adsorption sites for the target gas, shortening the response recovery time; ④ They exhibit high sensitivity and high selectivity at room temperature.

[0004] The fabrication of self-assembled peptide nanoarrays based on aromatic short peptides using physical vapor deposition (PVD) for the detection of acetone in human exhaled breath, and thus for early prevention of diabetes, is of great significance. Therefore, this invention innovatively designs a gas-sensitive material, directly depositing a self-assembled peptide nanoarray structure on an electrode using PVD technology and then combining it with ZnO. The prepared self-assembled peptide nanoarray / ZnO composite gas-sensitive material is then applied to a photoexcited acetone gas sensor. This method is simple and low-cost, and the gas sensor can detect and analyze human exhaled acetone at room temperature. The prepared acetone gas sensor can be applied to the room temperature and visible light excitation detection of acetone in human exhaled breath: by capturing changes in acetone concentration in exhaled breath, it enables early warning and non-invasive diagnosis of diabetes, providing a core sensing component for home health monitoring and portable medical testing devices. Summary of the Invention

[0005] The purpose of this invention is to propose the application of a self-assembled peptide nanoarray / ZnO composite gas-sensitive material in an acetone gas sensor. By introducing the self-assembled peptide nanoarray, ZnO nanoparticles can be effectively dispersed, promoting the adsorption and desorption of acetone gas. Furthermore, the photoelectric properties of the self-assembled peptide nanoarray can introduce additional photogenerated carrier channels into the composite material system, thereby improving gas-sensing performance. A method for preparing the self-assembled peptide nanoarray / ZnO composite gas-sensitive material is also proposed.

[0006] The self-assembled peptide nanoarray / ZnO composite gas-sensitive material was applied to a room-temperature acetone gas sensor under visible light excitation. Specifically, a ZnO suspension was drop-coated onto an interdigitated electrode sheet with the self-assembled peptide nanoarray deposited using a pipette. The interdigitated electrode sheet was then dried in an oven (drying conditions: drying temperature 30 ℃~80 ℃, drying time 2 h~8 h) to obtain the self-assembled peptide nanoarray / ZnO gas sensor. This sensor was then placed in a gas detection system for gas detection under visible light excitation and room temperature conditions.

[0007] Preferably, the visible light intensity is 4.7 mW / cm². 2 It has the best time-sensitive performance.

[0008] Furthermore, the fabrication process of the self-assembled peptide nanoarray / ZnO gas sensor is as follows:

[0009] Add 2 mg to 20 mg of ZnO nanoparticles to 2 ml to 10 ml of deionized water and sonicate (sonication time is 0.5 h to 2 h, ultrasonic power is 50% to 100%) to ensure that a uniformly dispersed ZnO suspension is obtained.

[0010] The concentration of the ZnO nanoparticle suspension has a significant impact on the gas-sensing response. Lower concentrations result in lower ZnO content and fewer available active sites, leading to a lower response. Conversely, excessively high concentrations cause ZnO to aggregate, also affecting the gas-sensing response value. Similarly, the volume of the ZnO suspension also affects the response. Preferably, the volume of the ZnO suspension is 40–100 µL, and the concentration is 1.0 mg / mL–10.0 mg / mL.

[0011] ZnO suspensions of different concentrations were drop-coated onto an electrode with a self-assembled peptide nanoarray deposited using a pipette. Uniform drop-coating ensured that the ZnO nanoparticles were uniformly dispersed on the surface of the self-assembled peptide nanoarray. Preferably, the deposition temperature was 200℃–300℃ and the deposition time was 30s–180s.

[0012] By changing the deposition time, the thickness and density of the self-assembled peptide nanoarray can be controlled. If the deposition time is too short, the self-assembled peptide nanoarray has not yet formed or the array gaps are too large, making it impossible to effectively disperse ZnO nanoparticles. If the deposition time is too long, the density and thickness of the self-assembled peptide nanoarray will be too large, and ZnO nanoparticles will not be able to penetrate into the array gaps, which is also not conducive to the dispersion of ZnO nanoparticles.

[0013] Finally, the prepared sample was dried in a forced-air drying oven to ensure the stability of the composite material and to form a strong gas-sensitive layer.

[0014] Furthermore, the self-assembled peptide nanoarray is prepared using physical vapor deposition (PVD) technology, and the specific process is as follows:

[0015] First, 5 mg–20 mg of phenylalanine dipeptide FF powder was placed in the vacuum chamber of a thermal evaporation deposition machine, while interdigitated electrodes were fixed on a substrate support. Evaporation was performed using PVD technology at a temperature of 200–300 °C for 30–180 s. During evaporation, the phenylalanine dipeptide FF molecules spontaneously self-assembled on the surface of the interdigitated electrodes through sublimation, forming a large-scale, highly ordered, and vertically aligned self-assembled peptide nanoarray. This porous array structure facilitates the dispersion of ZnO nanoparticles during sensor fabrication, provides more reactive sites, and promotes the diffusion of the target gas.

[0016] This invention applies a self-assembled peptide nanoarray to the field of gas sensors. The array structure possesses numerous pores and a large specific area, effectively adsorbing ZnO nanoparticles. This allows ZnO nanoparticles to form complete connection pathways on the surface of the self-assembled peptide nanoarray, facilitating electron transfer. The porous structure also promotes the diffusion of the target gas. The photoelectric properties of the self-assembled peptide nanoarray introduce additional photogenerated carrier channels into the composite material system, thereby enhancing gas-sensing performance. The self-assembled peptide nanoarray / ZnO composite gas-sensing material leverages the synergistic effect of the self-assembled peptide nanoarray and ZnO, exhibiting high selectivity for acetone and achieving efficient detection of exhaled acetone at room temperature. Furthermore, this sensor demonstrates a high response even to low concentrations of acetone.

[0017] This invention employs a self-assembled peptide nanoarray and ZnO nanoparticles to prepare a binary composite gas-sensitive material. An acetone sensor is fabricated using this self-assembled peptide nanoarray / ZnO binary composite material, achieving low detection limit, effective, and highly selective detection of acetone gas at room temperature under visible light excitation. This self-assembled peptide nanoarray / ZnO composite gas-sensitive material is applied to a non-invasive diagnostic sensor for diabetes, detecting acetone in human breath under visible light excitation at room temperature. By replacing blood sampling with breath testing, it achieves non-invasive, convenient, and home-based diagnosis and monitoring of diabetes, while ensuring detection accuracy—precisely distinguishing the difference in acetone concentration between healthy individuals (0.3-0.9 ppm) and diabetic ketoacidosis patients (≥1.8 ppm), meeting the sensitivity and specificity requirements of clinical diagnosis. This provides a new approach for non-invasive diabetes detection. Furthermore, phenylalanine dipeptide and ZnO materials are readily available, inexpensive, require minimal equipment investment, and involve a simple process. Attached Figure Description

[0018] Figure 1 The image shown is a scanning electron microscope image of the self-assembled peptide nanoarray (deposited for 60 s) in the example. The inset is a side view of the array.

[0019] Figure 2 Self-assembled peptide nanoarrays obtained at different deposition times;

[0020] Figure 3 The image shown is a scanning electron microscope image of the self-assembled peptide nanoarray / ZnO binary composite gas-sensitive material in the examples.

[0021] Figure 4 The following are gas-sensing response diagrams of the self-assembled peptide nanoarray / ZnO gas sensor at different acetone concentrations (1 ppm to 50 ppm) obtained by drop-coating ZnO gas sensor (ZnO concentration of 5 mg / ml) and ZnO suspensions of different concentrations (1 mg / ml, 3 mg / ml, 5 mg / ml, 7 mg / ml) in the examples.

[0022] Figure 5 The response recovery time test results of the acetone gas sensor prepared by drop-coating 5 mg / ml ZnO suspension in the example are shown in the example at an acetone concentration of 10 ppm.

[0023] Figure 6 The results show the selectivity and repeatability of the acetone gas sensor prepared by dropping a 5 mg / ml ZnO suspension in the examples for different gases. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0025] The specific process for preparing an acetone gas sensor is as follows:

[0026] First, 10 mg of phenylalanine dipeptide FF powder was placed in the vacuum chamber of a thermal evaporation deposition machine. Interdigitated electrodes were fixed on a substrate support, and evaporation was performed using PVD technology at 220 °C with a heating rate of 10 °C / min and a deposition time of 60 s. During evaporation, phenylalanine dipeptide FF molecules spontaneously self-assembled on the surface of the interdigitated electrodes through sublimation, forming a peptide self-assembled nanoarray. The scanning electron microscope image of the prepared self-assembled peptide nanoarray is shown below. Figure 1 As shown.

[0027] During the preparation process, the evaporation temperature and time during the self-assembly of the phenylalanine dipeptide are crucial, affecting the stability, thickness, and density of the self-assembled peptide nanoarray, and consequently, its gas-sensing performance. If the evaporation temperature is too low, the phenylalanine dipeptide FF powder cannot effectively sublimate and deposit; while a higher temperature will disrupt the π-π bonds between the benzene rings, making the structure of the resulting self-assembled peptide nanoarray unstable. Therefore, it is essential to control the deposition temperature carefully. If the evaporation time is too short, the self-assembled peptide nanoarray may not have formed or the inter-array gaps may be too large, hindering the effective dispersion of ZnO nanoparticles; conversely, a longer evaporation time results in an excessively high density of the self-assembled peptide nanoarray, preventing ZnO nanoparticles from penetrating the array gaps, which is also detrimental to ZnO nanoparticle dispersion. Figure 2 As shown, four self-assembled peptide nanoarrays were obtained with different deposition times. It can be seen that the self-assembled peptide nanoarrays prepared with deposition times ranging from 30s to 180s all have voids.

[0028] Next, 15 mg of ZnO was added to 3 ml of deionized water and sonicated for 1 h to obtain a uniformly dispersed ZnO suspension. 80 μl of this suspension was then drop-coated onto an electrode with a self-assembled peptide nanoarray deposited on it using a pipette. After drying at 40 °C for 4 h, an acetone gas sensor capable of room-temperature detection under visible light excitation was obtained. The scanning electron microscope image of the obtained self-assembled peptide nanoarray / ZnO binary composite gas-sensitive material (acetone gas sensor) is shown below. Figure 3 As shown.

[0029] The gas-sensing performance of the above-mentioned acetone gas sensor was tested at room temperature (test temperature approximately 26 ℃, irradiated with white light (wavelength 400–700 nm, light intensity 4.7 mW / cm²)). 2 (Dynamic gas loading) involves mixing target gas and carrier gas at different concentrations and injecting them into the test chamber at a total rate of 500 sccm. The specific concentration of the gas to be introduced is controlled by adjusting the gas flow meter, and the change in resistance value during the test is recorded using a source meter.

[0030] The gas-sensing characteristics of the acetone gas sensor at different acetone concentrations (1 ppm to 50 ppm) are shown in the figure below. Figure 4 As shown. From Figure 4 It can be seen that when detecting acetone gas at different concentrations, the response value of the self-assembled peptide nanoarray / ZnO sensor is higher than that of the pure ZnO sensor. As the ZnO concentration increases, the response value of the self-assembled peptide nanoarray / ZnO sensor shows a trend of first increasing and then decreasing. Among them, when the ZnO concentration is 5 mg / ml, the response value of the self-assembled peptide nanoarray / ZnO sensor is large, especially at a concentration of 50 ppm. At the same ZnO concentration, the response value of the self-assembled peptide nanoarray / ZnO sensor is nearly 4 times that of the pure ZnO sensor.

[0031] The response recovery time curve of the acetone gas sensor prepared by drop-coating a 5 mg / ml ZnO suspension at an acetone concentration of 10 ppm is shown in the figure below. Figure 5 As shown. From Figure 5 It can be seen that the response recovery time of the self-assembled peptide nanoarray / ZnO sensor is shorter than that of the pure ZnO sensor, indicating that the self-assembled peptide nanoarray / ZnO gas sensor can quickly test the target gas.

[0032] The selectivity test results of the acetone gas sensor prepared by drop-coating a 5 mg / ml ZnO suspension are as follows: Figure 6 As shown. From Figure 6It can be seen that, when testing different gases at the same concentration, the sensor shows the highest response value to acetone, which is significantly higher than that of other gases. This indicates that the prepared acetone gas sensor has excellent selectivity. Five cycles of testing demonstrate that the gas sensor also exhibits good reversibility.

[0033] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. The self-assembled peptide nanoarray / ZnO composite gas-sensitive material was applied to an acetone gas sensor under visible light excitation at room temperature. Specifically, ZnO suspension was drop-coated onto an interdigitated electrode sheet with a self-assembled peptide nanoarray deposited on it using a pipette. The interdigitated electrode sheet was then dried in an oven to obtain the self-assembled peptide nanoarray / ZnO gas sensor. The sensor was then placed in a gas detection system for gas detection under visible light excitation at room temperature.

2. The application as described in claim 1, characterized in that: The deposition temperature is 200℃~300℃, and the deposition time is 30s~180s.

3. The application as described in claim 1, characterized in that: The drying conditions of the oven are: drying temperature 30 ℃~80 ℃, drying time 2 h~8 h.

4. The application as described in claim 1, characterized in that: The visible light intensity is 4.7 mW / cm². 2 .

5. The application as described in claim 1, characterized in that: The fabrication process of the self-assembled peptide nanoarray / ZnO gas sensor is as follows: Add 2 mg to 20 mg of ZnO nanoparticles to 2 ml to 10 ml of deionized water and sonicate to ensure a uniformly dispersed ZnO suspension. On an electrode with a self-assembled peptide nanoarray deposited on it, ZnO suspensions of different concentrations were drop-coated using a pipette; uniform drop-coating ensured that ZnO nanoparticles were uniformly dispersed on the surface of the self-assembled peptide nanoarray. Finally, the prepared sample was dried in a forced-air drying oven to ensure the stability of the composite material and to form a strong gas-sensitive layer.

6. The application as described in claim 5, characterized in that: The ultrasonic treatment is as follows: ultrasonic time 0.5h to 2h, ultrasonic power 50% to 100%.

7. The application as described in claim 1 or 5, characterized in that: The self-assembled peptide nanoarray was prepared using physical vapor deposition (PVD) technology, and the specific process is as follows: First, 5 mg–20 mg of phenylalanine dipeptide FF powder was placed in the vacuum chamber of a thermal evaporation deposition machine, while the interdigitated electrodes were fixed on a substrate support. PVD technology was used to evaporate the powder at 200–300 °C for 30–180 s. During evaporation, the phenylalanine dipeptide FF molecules spontaneously self-assembled on the surface of the interdigitated electrodes through sublimation, forming a large-scale, highly ordered, and vertically aligned self-assembled peptide nanoarray. This porous array structure facilitated the dispersion of ZnO nanoparticles during sensor fabrication, provided more reactive sites, and promoted the diffusion of the target gas.

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