Sensing material for detecting isoprene in exhaled air and sensing equipment thereof

Abstract

The invention relates to a sensing material for detecting isoprene in exhaled air and sensing equipment thereof, the sensing material is an n-type In2O3-based semiconductor two-dimensional nanosheet with the thickness of 10-100 nm, p-type impurities Cr, Cu and Ni with the content of 0-10 wt.% are doped to construct a p-n heterojunction, 0-5 wt.% of uniformly distributed Pt nanoclusters with the diameter of 2-5 nm are loaded, the sensing detection lower limit of isoprene reaches 2 ppb, and the sensing material can be used for detecting isoprene in exhaled air. And the responsiveness to isoprene is 4-10 times that of other gases in expired air. The optimized sensing material is fixed on a sensing chip of one of interdigital and annular electrode structures and the like, and is integrated on the surface of the electrode of the sensing chip to serve as a sensitive layer interacting with isoprene molecules, and the prepared portable digital display sensor can detect the concentration of isoprene in expired gas of a potential lung cancer patient within 3 seconds. The method is low in cost, easy to obtain, noninvasive, simple and convenient to operate, rapid in detection and high in accuracy, greatly promotes non-invasive early screening and monitoring of lung cancer, and meets various medical scenes and health management requirements.

Description

Technical Field

[0001] The present invention relates to the field of medical diagnosis and daily home health monitoring equipment, and in particular to a sensing material for detecting ultra-trace isoprene in human breath, a key biomarker for early lung cancer, and a digital display portable sensing device for isoprene in breath. The device can be used for early clinical diagnosis of lung cancer and daily home health monitoring, and provides a cheap, readily available, safe, non-invasive and rapid lung cancer detection technology. Background Art

[0002] As the incidence of cancer continues to rise around the world, lung cancer has once again become the type of cancer with the most new cases worldwide. According to the 2022 global cancer data released by CA: A Cancer Journal for Clinicians on April 4, 2024, there were 2.48 million new cases of lung cancer, surpassing breast cancer to become the world's number one cancer. Lung cancer generally has no symptoms in the early stages, and only about 20% of patients are diagnosed in the first stage. If the tumor is removed surgically in time, the survival rate can reach 90%; while more than 40% of patients are diagnosed in the fourth stage, and the survival rate is less than 10%. This grim reality highlights the importance of early diagnosis and monitoring of cancer in order to reduce the mortality rate of patients.

[0003] Traditional cancer diagnostic methods, such as tissue biopsy and imaging tests, although accurate, are invasive and may cause physical and psychological discomfort to patients while increasing healthcare costs. Therefore, non-invasive diagnostic techniques, such as breath analysis, have received increasing attention due to their portability, reduced patient discomfort, and cost-effectiveness.

[0004] Volatile organic compounds (VOCs) produced during human metabolism are exhaled through breathing. Their concentration and type are related to specific disease states, providing potential biomarkers for disease diagnosis. In particular, the content of isoprene in the breath of lung cancer patients is closely related to the development of the disease. Studies have shown that the concentration level of isoprene can serve as an important basis for distinguishing lung cancer patients from healthy people.

[0005] Currently, methods for detecting isoprene in breath include solid phase microextraction-gas chromatography / mass spectrometry (SPME-GC / MS) and proton transfer mass spectrometry, etc. Although these technologies are accurate, they have limitations such as complex operation, bulky equipment, and delayed data acquisition. Therefore, developing a semiconductor chemiresistor-based gas sensing technology to achieve low-cost, portable, fast and real-time breath analysis has important clinical significance and practical value for the early diagnosis and monitoring of lung cancer.

[0006] However, due to the complexity of the components of the exhaled breath biological system and the isoprene concentration at the ppb level, it is urgent to develop highly sensitive, highly specific, fast-response, stable and reliable sensing materials and portable visual devices. The present invention designs isoprene sensing materials with excellent performance and integrates these sensing materials into portable visual devices, providing a simple and advanced means of health monitoring and disease diagnosis and treatment. Summary of the invention

[0007] The purpose of the present application is to address the above-mentioned problems existing in the prior art and to provide a sensing material for detecting isoprene in exhaled breath and a digital display portable sensing device thereof, which, while maintaining the simple structure of a traditional gas detector, not only eliminates or avoids the influence of exhaled humidity, interfering gases and ambient temperature to the greatest extent, but also reduces noise interference in the development of hardware equipment, thereby ensuring the sensitivity, selectivity and accuracy of isoprene detection, and has optimization functions such as self-calibration, thereby providing service convenience to users to the greatest extent.

[0008] In order to achieve the above application purpose, the present application adopts the following technical solution: a sensing material for detecting isoprene in exhaled breath, wherein the sensing material is an n-type In2O3-based semiconductor two-dimensional nanosheet, the thickness of the nanosheet is 10-100nm, and the pore size of the nanosheet is a mesopore of 2-50nm.

[0009] It should be noted that the sensing material for detecting isoprene in exhaled breath provided in this scheme has an excellent ppb-level isoprene detection limit, a low sensing temperature, good moisture resistance, strong selectivity and cyclic stability, and is suitable for the detection of ultra-trace isoprene concentrations in exhaled breath, and can be integrated on the electrode surface of a sensor chip as a sensitive layer that interacts with isoprene molecules.

[0010] Furthermore, the sensing material is a pn heterojunction in which p-type impurities Cr, Cu, and Ni are doped with 0-10 wt.% on an n-type In2O3-based semiconductor two-dimensional nanosheet substrate to improve the moisture resistance of the material.

[0011] Furthermore, the sensing material has excellent moisture resistance. Under an environmental humidity of 0-100 RH%, the current baseline drift and the response value are both offset by less than 5%.

[0012] Further, the pn heterojunction is uniformly loaded with Pt nanoclusters, wherein the diameter of the Pt nanoclusters is 2-5nm. Specifically, the sensing material is loaded with Pt active sites on the surface of the In2O3-based semiconductor two-dimensional nanosheet substrate with a pn heterojunction, and the size of the Pt sites is regulated and evenly distributed. Preferably, the sensing material is anchored and loaded with 0-5wt.% Pt on the surface of the In2O3-based semiconductor two-dimensional nanosheet substrate with a pn heterojunction, wherein the diameter of the Pt nanoclusters is 2-5nm and is evenly distributed on the surface of the In2O3-based semiconductor two-dimensional nanosheet substrate with a pn heterojunction, that is, this scheme obtains Pt nanoclusters with a diameter of 2-5nm by regulating the size of the Pt active sites and evenly distributing them.

[0013] Furthermore, the sensing material has a low detection limit and low-temperature sensitivity. At an operating temperature of 150-350°C, the device has a detection limit of 2-500 ppb.

[0014] Furthermore, the specific response of the sensing material to isoprene is much higher than that to other gases such as carbon dioxide, ammonia, acetone, ethane, and methyl mercaptan in exhaled breath. The responsiveness of isoprene is 4-10 times that of other gases.

[0015] Furthermore, the isoprene sensing cycle stability is not less than 9 times, and the time is not less than 1.6h.

[0016] Furthermore, after structural regulation and surface modification, the proportion of surface active oxygen in the sensing material increases, providing good matrix conditions for electron exchange in gas-sensitive reactions.

[0017] In a second aspect, the present solution provides a digital display portable sensing device, including a semiconductor gas sensor, wherein the surface of a sensor chip electrode of the semiconductor gas sensor is integrated with a sensing material for detecting isoprene in exhaled breath, and the sensing material for detecting isoprene in exhaled breath serves as a sensing layer that interacts with isoprene molecules, wherein the sensor chip electrode is one of a forked finger electrode, a ring electrode, a grid electrode, a strip electrode, an array electrode, a microfluidic electrode, a segmented electrode, and a three-electrode system.

[0018] In other words, this solution uses the chip electrode substrate mentioned above to integrate and calcine the semiconductor gas sensor to stabilize it, and obtains a digital display portable sensing device through complex circuit integration such as independent heating electrodes.

[0019] Furthermore, the method for integrating the sensing material for detecting isoprene in breath into the sensing chip electrode on the semiconductor gas sensor includes:

[0020] Prepare an ethanol slurry containing 10-80% solid content of the sensing material and rotate it at 300-2000 r·min at room temperature. -1 The mixture was stirred at a rate of 100-200 °C for more than 0.5-12 h, 1-50 μL of the ethanol slurry was transferred with a pipette and dropped onto the electrode surface of the sensor chip on the semiconductor gas sensor. After drying at room temperature, the mixture was transferred to a muffle furnace and calcined at 150-450 °C for 2-24 h in an air atmosphere.

[0021] Furthermore, the digital display portable sensor device can detect the isoprene concentration in the breath of potential lung cancer patients within 0.01-3 seconds, and the sensing value returns to zero within 0.01-6 seconds.

[0022] Furthermore, when the digital display portable sensor device tests that the isoprene concentration in the breath of a potential lung cancer patient is lower than the isoprene concentration in the breath of a healthy person, the test subject is screened as a potential lung cancer patient.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention can be used to conveniently perform breath analysis and detection, and the breath analysis method has natural advantages over traditional lung cancer diagnosis and examination methods. The rapid, real-time, and non-invasive monitoring method is more easily accepted by patients, avoiding the fear and resistance of patients caused by invasive examinations such as CT examinations, needle aspiration biopsy, and respiratory endoscopy. It has the advantages of convenience, safety, and low cost, which reduces the burden on the medical system. Moreover, the design based on semiconductor chemical resistance sensors greatly reduces the manufacturing cost compared to traditional chromatography or mass spectrometry. At the same time, by selecting a variety of sensing material combinations, it can be optimized for different populations and environmental conditions, thereby improving the popularity and scope of application of detection technology.

[0025] 2. The present invention detects the concentration of isoprene in exhaled breath through gas sensing technology, and can achieve a detection limit of 2ppb, which is the lowest detection limit reported in the literature so far, and it can still operate stably in the presence of humidity and other interfering gases. That is, by selecting specific semiconductor sensing materials, especially the optimized n-type In2O3 and its doped p-type impurity NiO, and Pt@InNiO loaded with precious metal Pt x The material can show high sensitivity and selective response to isoprene molecules in exhaled breath, greatly improving the accuracy and reliability of detection, and contributing to the early detection of lung cancer. In addition, the use of nano-scale sensing materials, especially two-dimensional nanosheet structures, effectively increases the specific surface area of ​​the material, shortens the time of gas adsorption and desorption, and enables the sensing device to achieve rapid response and recovery to changes in isoprene concentration, meeting the needs of instant detection.

[0026] 3. The device of the present invention is compact and lightweight in design. It combines the intuitive display interface and human-computer interaction function of the output module and the remote upgrade function integrated in the control module. It is not only easy to carry, but also can realize remote updating and maintenance. It is suitable for a variety of application scenarios, including home self-testing, mobile medical care and on-site screening, etc., which greatly improves the user experience and medical service efficiency. In addition, the present invention can not only provide isoprene gas detection, but also can be expanded to other gas detection by changing software parameters and sensors.

[0027] 4. The sensing material of the present invention is an In2O3-based semiconductor metal oxide with a thickness of 10-100nm, doped with p-type impurities Cr, Cu, and Ni at a content of 0-10wt.%, constructing a pn heterojunction, and loading Pt at a content of 0-5wt.%, obtaining a 2-5nm Pt nanocluster as an active site, catalytically activating the conjugated double bond structure of isoprene, and the detection limit of isoprene reaches 2ppb, the sensing temperature is 150-350°C, and the specific response to isoprene is much higher than that of carbon dioxide, ammonia, acetone, ethane, methyl mercaptan and other types of gases in exhaled air. The responsiveness of isoprene is 4-10 times that of other gases, and the sensing cycle stability is not less than 9 times, and the time is not less than 1.6h. Under an environmental humidity of 0-100RH.%, the current baseline drift and the response value are both offset by less than 5%, which meets the concentration detection of ultra-trace isoprene in exhaled air. The optimized sensing material is fixed on a sensor chip with one of multiple electrode structures such as forked fingers and rings, and integrated on the surface of the sensor chip electrode as a sensitive layer that interacts with isoprene molecules. The prepared portable digital sensor can detect the isoprene concentration in the breath of potential lung cancer patients within 3 seconds. The isoprene concentration in the breath of lung cancer patients is lower than that in the breath of healthy people, and lung cancer patients are successfully identified. The present invention is cheap, easy to obtain, non-invasive, easy to operate, fast in detection speed, and high in accuracy, which greatly promotes the non-invasive early screening and monitoring of lung cancer and meets the needs of various medical scenarios and personal health management. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A physical picture of the digital display portable sensor device of the present invention;

[0029] Figure 2 This is a schematic diagram of the internal structure of a semiconductor gas sensor in a detection module of a digital display portable sensor device of the present invention;

[0030] Figure 3 The Pt@InNiO of the present invention x SEM image of nanosheets;

[0031] Figure 4 To observe Pt@InNiO under dark field transmission electron microscopy (HAADF-STEM) xAnd the distribution of Pt, In, Ni, and O elements under EDS-mapping scanning;

[0032] Figure 5 The nitrogen adsorption-desorption isotherms and pore size distribution of In2O3-based materials;

[0033] Figure 6 The dynamic response curves of the In2O3-based series sensors exposed to different concentrations of isoprene at 200℃;

[0034] Figure 7 Pt@InNiO x Sensor selectivity test;

[0035] Figure 8 Pt@InNiO x Sensor stability test;

[0036] Fig. 9 In2O3, InNiO x 、Pt@InNiO x Stability and responsiveness test of the sensor exposed to different humidity

[0037] Fig.10 This is a schematic diagram of the breath sample collection process;

[0038] Fig.11 Schematic diagram of the real-time process of testing the breath sample of lung cancer patient Wang.

[0039] Fig.12 Statistical analysis of test results for healthy subjects and lung cancer subjects.

[0040] In the figure, 1, output module; 2, control module; 3, detection module; 31, semiconductor gas sensor; 311, base; 312, tube cap; 313, sensor chip electrode; 314, pin; 315, metal wire mesh; 316, lead; 317, insulating substrate; 318, sensing material. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0042] Those skilled in the art should understand that, in the disclosure of the present application, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present application.

[0043] Example 1

[0044] The synthesis of In2O3 nanosheets is prepared by hydrothermal method. 0.2-3mmol InCl3 is dissolved in deionized water, 1-10mmol 2-aminothiophenol is dissolved in anhydrous ethanol, and the InCl3 aqueous solution is added dropwise to the 2-aminothiophenol ethanol solution under stirring. The mixture is transferred to a reactor, reacted at 160-220℃ for 6-20h, and the precursor solution is obtained after cooling to room temperature. After centrifugal washing with deionized water and anhydrous ethanol, it is placed in a vacuum oven at 45-80℃ for 3-12h to obtain a solid powder. The obtained solid powder is transferred to a crucible and calcined at 350-500℃ in an air atmosphere of a muffle furnace for 1-6h to finally obtain In2O3 nanosheets.

[0045] Example 2

[0046] InCrO x 、InCuO x 、InNiO x The nanosheets are made by doping In2O3 with Cr, Cu and Ni. The specific synthesis steps refer to Example 1. When InCl3 is dissolved, specific substances are added in amounts of Cr(NO3)3·9H2O, Cu(NO3)2·3H2O and Ni(NO3)2·6H2O to make the molar ratio of In:Cr, In:Cu and In:Ni 30:1-3:1. The other synthesis steps are the same as those in Example 1. Finally, InCrO x 、InCuO x 、InNiO x Nanosheets.

[0047] Example 3

[0048] Pt@InNiO x Nanosheets are InNiO x Based on the synthesis of Example 2, 0.01-.g chloroplatinic acid was dissolved in deionized water, and 0.2-10g InNiO xThe powder was stirred vigorously at room temperature for more than 12 h, heated to dryness, and transferred to a muffle furnace and calcined at 350-500 °C in an air atmosphere for 1-h to obtain Pt@InNiO x Nanosheet powder.

[0049] Example 4

[0050] like Figure 1 As shown in the figure, the actual picture of the digital display portable sensor device for detecting isoprene lung cancer in breath is shown in Figure 1 As shown, its functions are mainly divided into output module 1, control module 2, and detection module 3.

[0051] Output module 1 is presented in the form of a large-screen digital display screen, located on the left side of the device, and displays real-time isoprene detection concentration, accuracy, test range, concentration unit, detection progress (presented in the form of a progress bar), date, clock, ambient temperature, battery power and other information. During the processes of power-on preheating, self-test, inhalation, exhalation, emptying and self-calibration, the working status can be displayed in real time and the status can be automatically switched, prompting the user to confirm or directly proceed to the next step, and prompting and correcting errors during the operation.

[0052] Control module 2, located on the right side of output module 1, includes a power button, indicator light, setup, and up, down, left, and right control buttons. The setup control options include alarm settings, record management, instrument zeroing, system settings, parameter settings, instrument calibration and other options. In the alarm settings, the A1 channel can set parameters such as high alarm, low alarm, high alarm hysteresis, and low alarm hysteresis. In the record management, the A1 channel can store more than 2000 historical records, alarm records, and fault records respectively, and the storage interval defaults to 5 minutes. In the instrument zeroing, the A1 channel sets zero point calibration to zero the instrument. In the system settings, the system clock can be set to real-time time, including year, month, day, hour, and minute, accurate to seconds; the gas flow rate defaults to 600mL·min -1 ; The detection mode is real-time detection; there are also system setting options such as password modification, language selection, and factory reset. Parameter setting A1 channel gas type is isoprene, accuracy is 0.1, range defaults to 999.9, concentration units can be set to ppm, ppb, mg·m -3 , LEL, vol.%, etc. Use standard gases with known concentrations (25, 50, 100, 200, 600) to calibrate the instrument and obtain the corresponding AD value. According to a series of standard values ​​and corresponding AD values, a calibration curve is established by linear regression or other fitting methods. The calibration coefficient, i.e., the slope and intercept of the linear regression, is calculated from the calibration curve. The measured AD value is converted into the corresponding standard value through the calibration coefficient to verify the accuracy and reliability of the calibration result.

[0053] Detection module 3 is Figure 1 The schematic diagram of the semiconductor gas sensor 31 in the white breath detection area is similar to the schematic diagram of the semiconductor sensor chip as shown in FIG. Figure 2 As shown. The semiconductor gas sensor 31 (hereinafter referred to as the sensor) is composed of a metal mesh 315, a metal cap 312, a base 311 and pins 314. The metal mesh 315 is used to effectively filter gas and transmit. The upper part of the base 311 includes a support structure for supporting the semiconductor sensor chip and maintaining a fixed position and contact stability. The pins 314 at the bottom of the base 311 are used to sense the transmission of electrical signals and are connected to the circuit inside the device.

[0054] In this embodiment, the enlarged detail of the semiconductor sensor chip supported by the upper portion of the base 311 is shown in FIG. Figure 2 As shown on the right, the semiconductor sensor chip is composed of a lead 316, a sensor chip electrode 313, an insulating substrate 317, and a Pt@InNiO x The sensor chip electrode 313 plays the role of sensor signal conversion and signal amplification processing. Common electrode layouts include interdigital electrodes, ring electrodes, grid electrodes, strip electrodes, array electrodes, microfluidic electrodes, segmented electrodes, and three-electrode systems. The specific embodiment of the present invention is preferably an interdigital electrode. It is worth mentioning that Figure 2 The size of the sensor chip is for reference only. Sensor chips of any size are suitable for the corresponding type of semiconductor gas sensor 31.

[0055] Example 5

[0056] The sensing material 318 is preferably an n-type semiconductor metal oxide In2O3, which has a high 2 ·V -1 ·s -1 The electron mobility of In2O3 is high. Compared with widely studied n-type semiconductors such as ZnO, SnO2 and WO3, In2O3 has a high defect site concentration and high catalytic activity, and can detect reducing gases at relatively low operating temperatures. The preferred morphological structure is a two-dimensional nanosheet structure. The thickness and sheet size of the nanosheet are controlled at a scale of tens to hundreds of nanometers, and the specific surface area and porosity of the nanosheet are regulated to mesopores or macropores of 2-50nm. P-type impurities Cr, Cu, and Ni are doped on the n-type In2O3 nanosheet substrate, preferably Ni is doped, and 1wt.% Pt is preferably loaded on the surface of the nanosheet material, and the size of the Pt site is regulated and evenly distributed. Pt@InNiO x The morphology and structure of nanosheet materials are as follows Figure 3As shown in the figure, the thickness of the nanosheet is about 10nm. The clustered nanosheet structure increases the contact opportunity with gas molecules, thereby enhancing the gas sensing effect. Pt@InNiO was observed under a dark field transmission electron microscope (HAADF-STEM). x And do EDS-mapping scan to determine the element distribution, such as Figure 4 As shown in Figure 2, Pt is adsorbed on the sample surface in the form of nanoclusters of about 2 nm, and each element component is evenly distributed. Surface characterization information such as nitrogen adsorption and desorption is shown in Figure 2. Figure 5 As shown in the following Table 1:

[0057] Table 1

[0058]

[0059] Example 6

[0060] In the embodiment of the present invention, Pt@InNiO x We conducted multi-dimensional performance evaluation tests suitable for breath analysis, including optimal operating temperature test, dynamic responsiveness test, selectivity test, cycle stability test, and moisture resistance test. The test results show that Figure 6 As shown, it has a detection limit of 2 ppb at an operating temperature of 200°C; Figure 7 In the selective test shown, Pt@InNiO x The response to isoprene is at least 4 times that of other gases; the response reproducibility is good under multiple cycles, proving the reliability and accuracy of the response data, such as Figure 8 As shown; when exposed to 0-100R.H.% relative humidity environment, Pt@InNiO x The baseline state is basically not affected by humidity changes, and the responsiveness is not reduced, such as Fig. 9 In summary, Pt@InNiO x At an operating temperature of 200°C, it exhibits high responsiveness, selectivity, stability, and an excellent 2 ppb detection limit for low-concentration isoprene gas, which is the lowest detection limit reported for isoprene sensing to date. x As a high-performance sensing material, it has high application potential in the sensing analysis of isoprene in exhaled breath.

[0061] Example 7

[0062] In the embodiment of the present invention, considering the flexibility of the sensor chip integration method, the applicability of the material properties and the cost factor, the drop coating method is preferably used as the integration of the nanosheet material on the sensor chip. The specific method is as follows: prepare a 30% solid content Pt@InNiOx Ethanol slurry, at room temperature, 800 r min -1 The mixture was stirred at a rate of 1000 μg / min for more than 6 hours, and 3 μL was transferred with a pipette and dropped onto the sensor chip. After drying at room temperature, it was transferred to a muffle furnace and calcined at 220°C for 12 hours in an air atmosphere to improve its mechanical stability. The back of the sensor chip has a self-integrated heating electrode to provide the required temperature conditions. The four leads 316 of the electrode substrate are respectively connected to the four pins 314 of the sensor according to the markings to ensure correct signal input and temperature control.

[0063] The development process of the digital display portable exhalation device includes demand analysis, concept design, technology research and development, prototype production and clinical verification stages. In the demand analysis stage, the device aims to provide lung cancer patients with services such as home health monitoring, medical institution analysis and testing, sports medicine training, and health management planning, avoiding the fear and resistance of patients to invasive examinations such as CT examinations, needle aspiration biopsy, and respiratory endoscopy, and providing real-time health self-examination functions. It has the advantages of convenience, safety, and low cost, while reducing the burden on the medical system. In the conceptual design stage, the device integrates the semiconductor gas sensor 31 into the portable exhalation device, and integrates the sample collection, signal processing, and data display functions. Through the display interface, users can easily obtain health warnings about low concentrations of isoprene, ensuring user friendliness and ease of operation, and having the advantages of portability and data reliability. In the technical research and development stage, the hardware circuits required for the device are developed, including sensor interfaces, data acquisition modules, signal processors, etc., and the software system is developed, including embedded programs, user interface design, data processing algorithms, etc. The data processing and analysis algorithms are optimized to improve the detection accuracy and real-time performance of the device for isoprene concentrations.

[0064] Example 8

[0065] The present invention provides a digital display portable sensor device, and the specific use method thereof comprises the following steps:

[0066] S00. Collection of breath samples:

[0067] When collecting breath samples, in order to exclude interference from other factors, the basic information of the subjects was recorded, including age, gender, lung cancer stage, diabetes history and smoking history. In order to ensure the quality of sampling, all volunteers were required not to engage in strenuous exercise or eat within 3 hours before sampling.

[0068] S10. Sample testing:

[0069] After adjusting the control module 2 of the device according to the instructions in the specific implementation, start the sample testing work. Squeeze the breath sample in the gas sample bag into the white breath sensor area of ​​the digital portable breath sensor device, and the isoprene concentration is displayed in real time on the output module 1 of the device. The sensor completes the response to a breath sample within 10 seconds and returns to the initial state.

[0070] S20. Statistics and analysis of results:

[0071] According to the isoprene concentration values ​​output by the digital display screen of the equipment, record and compare them. Combined with the overall test results, discuss the relationship between the isoprene concentration value and age, gender, lung cancer stage, diabetes history and smoking history.

[0072] Example 9

[0073] Based on Example 8, actual tests were conducted. The volunteers for the collection of breath samples were lung cancer patients from the Department of Critical Care Medicine of the Second Affiliated Hospital of Zhejiang University School of Medicine and healthy people from the Quzhou Branch of the School of Engineering of Zhejiang University. When collecting breath samples, in order to eliminate the interference of other factors, the basic information of the volunteers was recorded, including age, gender, lung cancer stage, history of diabetes and smoking history. This example will compare the effects of these variables on the test results. In order to ensure the quality of sampling, all volunteers were required not to engage in strenuous exercise or eat within 3 hours before sampling. The breath samples were collected using a 0.5L polyvinyl fluoride (PVF, Tedlar) gas sample bag. The breath schematic diagram and sample collection process are shown in the figure. Fig.10 As shown. In this example, breath samples of 10 volunteers were collected, including 5 lung cancer patients, 5 healthy individuals, and 1 indoor air sample. Taking the breath sample test process of lung cancer patient Wang as an example, the implementation process is as follows Fig.11 shown.

[0074] By testing the collected breath samples and indoor air samples, the information and test results of the 10 subjects are shown in Table 2 below:

[0075] Table 2

[0076]

[0077] Combined with the overall test results, the test results of the digital display portable breath sensor device show that the level of isoprene concentration is closely related to the stage of lung cancer. The lung cancer stages of Lai. and Wang. were Ⅲ-C and Ⅲ-A, respectively, and the measured isoprene concentrations in the breath were 34.3 and 33.2, respectively. The isoprene concentrations in the breath of the other three patients with lung cancer stage Ⅳ ranged from 27.4 to 30.3, which preliminarily proved that the digital display portable breath sensor device designed and developed in this study has a certain ability to classify lung cancer stages. The comparison between Fan. and Weng. healthy individuals preliminarily proved that the isoprene concentration in the breath decreases with age. Gender, history of diabetes, smoking history and other factors have little effect on the test results and are within the allowable range of test error. The measured concentration value of the indoor air sample is zero, and there is no need to subtract the air background from the above test concentration values. The isoprene concentration values ​​in the breath of lung cancer patients and healthy people measured in Table 2 are compared with the health status of the subjects. Fig.12 It can be seen that the exhaled isoprene concentration of lung cancer patients is consistently lower than 40 ppb, while the exhaled isoprene concentration of healthy individuals exceeds 60 ppb, which forms a clear contrast and proves the clinical effectiveness of the digital display portable breath sensor device designed and developed in this study.

[0078] The parts not described in detail in this application are prior art, so this application does not describe them in detail.

[0079] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0080] Although this article uses more terms such as output module 1, control module 2, detection module 3, semiconductor gas sensor 31, base 311, cap 312, sensor chip electrode 313, pin 314, wire mesh 315, lead 316, insulating substrate 317, and sensing material 318, it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of this application; interpreting them as any additional restrictions is contrary to the spirit of this application.

[0081] The present application is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of this application. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present application.

Claims

1. A sensing material for detecting isoprene in breath, characterized in that: The sensing material is an n-type In2O3-based semiconductor two-dimensional nanosheet, the thickness of the nanosheet is 10-100nm, and the pore size of the nanosheet is a mesopore of 2-50nm.

2. A sensing material for detecting isoprene in breath as claimed in claim 1, characterized in that: The sensing material is a pn heterojunction formed by doping p-type impurities Cr, Cu and Ni with a content of 0-10 wt.% on an n-type In2O3-based semiconductor two-dimensional nanosheet substrate.

3. A sensing material for detecting isoprene in breath according to claim 2, characterized in that: Pt nanoclusters are uniformly loaded on the pn heterojunction, where the diameter of the Pt nanoclusters is 2-5 nm.

4. A sensing material for detecting isoprene in breath as claimed in claim 1, characterized in that: The detection limit is 2-500 ppb at an operating temperature of 150-350°C, and the specific response to isoprene is 4-10 times that to carbon dioxide, ammonia, acetone, ethane, and methyl mercaptan gases in breath.

5. A sensing material for detecting isoprene in breath as claimed in claim 1, characterized in that: The sensing cycle stability of isoprene is not less than 9 times, and the time is not less than 1.6h.

6. A sensing material for detecting isoprene in breath as claimed in claim 1, characterized in that: Under the environment humidity of 0-100RH%, the current baseline drift and the response value deviation are less than 5%.

7. A digital display portable sensor device, characterized in that: It comprises a semiconductor gas sensor, wherein the surface of a sensor chip electrode of the semiconductor gas sensor is integrated with a sensing material for detecting isoprene in breath as described in any one of claims 1 to 6, and the sensing material for detecting isoprene in breath serves as a sensing layer that interacts with isoprene molecules, wherein the sensor chip electrode is one of an interdigitated electrode, a ring electrode, a grid electrode, a strip electrode, an array electrode, a microfluidic electrode, a segmented electrode, and a three-electrode system.

8. A digital display portable sensing device according to claim 7, characterized in that: The method for integrating the sensing material for detecting isoprene in breath into a semiconductor gas sensor comprises: preparing an ethanol slurry containing 10-80% solid content of the sensing material for detecting isoprene in breath according to claim 1 and rotating the slurry at 300-2000 r·min at room temperature. -1 The mixture was stirred at a rate of 100-200 °C for more than 0.5-12 h, 1-50 μL of the ethanol slurry was transferred with a pipette and dropped onto the electrode surface of the sensor chip on the semiconductor gas sensor. After drying at room temperature, the mixture was transferred to a muffle furnace and calcined at 150-450 °C for 2-24 h in an air atmosphere.

9. A digital display portable sensing device according to any one of claims 7-8, characterized in that: The digital display portable sensor device is used to detect the isoprene concentration in the breath of potential lung cancer patients within 0.01-3 seconds, and the sensing value returns to zero within 0.01-6 seconds.

10. A digital display portable sensing device according to any one of claim 9, characterized in that: When the digital display portable sensor device tests that the isoprene concentration in the breath of a potential lung cancer patient is lower than the isoprene concentration in the breath of a healthy person, the person being screened is a potential lung cancer patient.

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