A wearable exhaled breath acetone detection method and device based on MXene

Abstract

The present invention discloses a wearable exhaled breath acetone detection method and device based on MXene. The device includes an exhaled breath acetone detection tag. The exhaled breath acetone detection tag is assembled from a MXene acetone sensor, a flexible detection circuit board, a polydimethylsiloxane encapsulation layer, and a light-emitting diode circuit board, and is used to detect the acetone concentration in the exhaled breath. The present invention utilizes wireless Bluetooth between the MXene device and the mobile terminal for data interaction to achieve continuous and real-time monitoring of the dynamic changes in the exhaled breath acetone concentration, and reflects the intensity of lipid metabolic activities such as diet and fat burning exercise, thereby achieving daily metabolic health management. The method provides a wearable detection platform for exhaled breath analysis, which has the advantages of non-invasiveness, continuous real-time, simple operation, and rapid detection.

Description

Technical Field

[0001] The present invention relates to a technology for detecting exhaled breath acetone, and in particular to a wearable exhaled breath acetone detection method and device based on MXene. Background Art

[0002] Exhaled breath acetone is an important product of lipid metabolism and is considered one of the most attractive targets for lipid metabolism monitoring. Clinical evidence shows that acetone is produced by a series of oxidation reactions of fatty acids in liver mitochondria and is mainly excreted from the body through exhaled breath. Therefore, exhaled breath acetone has a clear metabolic source and pathway, and can reflect the lipid metabolism related to daily activities such as eating habits and physical exercise. Studies have shown that the exhaled breath acetone concentration of healthy subjects ranges from hundreds of ppb (parts per billion) to 0.9 ppm (parts per million), and can significantly increase to tens or hundreds of ppm after fasting, ketogenic diet, or aerobic exercise. Therefore, exhaled breath acetone detection has great potential in guiding weight loss, evaluating exercise endurance, or guiding ketoacidosis treatment, and is expected to be applied to clinical practice. In addition, compared with the biochemical analysis of blood ketone detection, exhaled breath analysis has the outstanding advantages of simple and non-invasive sampling, which is less burdensome to the subject being tested, so it has great prospects in medical diagnosis and personalized health care.

[0003] At present, standard exhaled breath detection often relies on desktop analytical instruments, such as gas chromatography-mass spectrometry, selective ion flow tube mass spectrometry, etc. These methods are suitable for laboratory or hospital examinations, but are difficult to be widely applied to daily personal metabolic health monitoring. Therefore, the development of portable, wearable miniaturized exhaled breath sensing detection solutions can serve as an important supplement to clinical standard exhaled breath detection. In recent years, the emerging family of two-dimensional transition metal carbides and nitrides nanomaterials (MXenes) has received great attention in sensor development, mainly due to their excellent properties such as metallic conductivity, highly chemically active surface and high signal-to-noise ratio. Therefore, MXenes have unique appeal in designing room temperature gas sensors with high sensitivity and low detection limit. In addition, recent studies have shown that masks worn daily can not only provide protection for individuals, but can also be combined with sensing materials to achieve wearable detection of viruses and biochemical markers in exhaled breath. Therefore, in order to address the detection application bottlenecks such as high humidity, multiple interferents, and sensor response drift in exhaled breath detection, a set of MXene smart mask devices and methods for exhaled breath acetone detection integrating interferent filtration, sensor detection, response correction and wireless data transmission were developed based on the MXene nanomaterial platform and disposable masks. This is of great significance for promoting wearable respiratory analysis and daily lipid metabolism management. Summary of the invention

[0004] The purpose of the present invention is to provide a wearable exhaled breath acetone detection method and device based on MXene in view of the deficiencies of existing technologies and products, so as to realize continuous real-time wearable detection of exhaled breath acetone in daily life, reflecting the diet and exercise health management related to lipid metabolism.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A wearable exhaled breath acetone detection device based on MXene, comprising: an exhaled breath acetone detection tag; the exhaled breath acetone detection tag comprises a MXene acetone sensor, a flexible detection circuit board, a polydimethylsiloxane encapsulation layer for encapsulating the flexible detection circuit board, and a light-emitting diode circuit board, which are assembled in sequence from bottom to top, the light-emitting diode circuit board comprises a light-emitting diode substrate, and a light-emitting diode fixed on the light-emitting diode substrate, the flexible detection circuit board and the polydimethylsiloxane encapsulation layer are provided with windows, so that the light-emitting diode faces the MXene acetone sensor; the diode circuit board, the MXene acetone sensor and the flexible detection circuit board are electrically connected; wherein the MXene acetone sensor is used to detect the acetone concentration in the exhaled breath and convert it into an electrical signal, and the flexible detection circuit board is used to obtain and process the electrical signal of the MXene acetone sensor; the MXene acetone sensor comprises a sensor substrate, a gold interdigital electrode and a MXene nanosensing layer, which are assembled in sequence from bottom to top, and the surface of the MXene nanosensing layer is modified with titanium dioxide nanoparticles and short peptide molecules.

[0007] Furthermore, the MXene nanosensing layer is prepared by mixing 2 parts by mass of ceramic phase titanium aluminum carbon powder with 2 parts by mass of lithium fluoride and dissolving them in 40 parts by volume of concentrated hydrochloric acid, etching at 40°C for 24 hours, washing the precipitate with deionized water, and spraying it on the surface of the gold interdigital electrode after ultrasonic mechanical stripping assisted by a vortex generator.

[0008] Furthermore, the titanium dioxide nanoparticles are modified by the following method: a MXene nanosensing layer is mixed with a 3% by mass hydrogen peroxide solution, and the mixture is heated in a water bath at 80° C., and the titanium dioxide nanoparticles are in situ grown on the MXene nanosensing layer.

[0009] Furthermore, the short peptide molecule is modified by the following method: the MXene nanosensing layer with in-situ grown titanium dioxide nanoparticles is mixed and dissolved in a mass ratio of 1:2, and 0.005 mass parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine catalyst are added respectively, and the mixture is stirred at 100°C for 3 hours to obtain a MXene nanosensing layer co-modified with titanium dioxide nanoparticles and short peptide molecules.

[0010] Furthermore, it also includes a MXene-based fabric filter for filtering exhaled breath; the MXene-based fabric filter is composed of a platinum nanoparticle-loaded MXene fabric and an active desiccant wrapped in the platinum nanoparticle-loaded MXene fabric, and the platinum nanoparticle-loaded MXene fabric is obtained by electrostatically adsorbing MXene on the surface of cotton fabric, and then in-situ reducing the loaded platinum nanoparticles on the MXene surface in a chloroplatinic acid solution.

[0011] Furthermore, the platinum nanoparticle-loaded MXene fabric is prepared by the following method: a white cotton fabric washed with deionized water and dried is immersed in a 5 mg / mL MXene solution, deposited for 30 minutes, repeatedly washed and dried, and then immersed in a 3.86 mM chloroplatinic acid solution for 30 minutes, and reacted by using the chemically active surface of MXene to achieve in-situ reduction of platinum nanoparticles.

[0012] Furthermore, the flexible detection circuit board is composed of a detection circuit substrate, a detection circuit, a diode circuit connection pad and a sensor connection pad. The detection circuit substrate is composed of a polyimide film. The detection circuit mainly includes a micro low-power chip and peripheral resistors and capacitors, which are used to obtain and process the electrical signal of the MXene acetone sensor; the light-emitting diode circuit board and the MXene acetone sensor are respectively welded to the diode circuit connection pad and the sensor connection pad by low-temperature soldering to realize the electrical connection between the diode circuit board, the MXene acetone sensor and the flexible detection circuit board.

[0013] Furthermore, the detection circuit is composed of a microcontroller, a constant current source, an analog-to-digital converter, Bluetooth, a low-pass network, a field effect transistor, a light-emitting diode, a battery and a power management circuit, and peripheral resistors and capacitors.

[0014] Furthermore, it also includes a disposable mask, a breathing valve fixed on the disposable mask and a breathing valve housing, the exhaled air acetone detection label is fixed between the breathing valve on the outside of the disposable mask and the breathing valve housing, and the MXene-based fabric filter is fixed on the breathing valve on the inside of the disposable mask to filter the exhaled air passing through the breathing valve.

[0015] Based on the same principle, the present invention also provides a method for detecting acetone in exhaled breath based on MXene, specifically:

[0016] The acetone concentration of the exhaled breath was obtained using the above device, and the light emitting diode was kept turned on during the acetone detection period.

[0017] In the detection method of the present invention, the exhaled air is filtered through a MXene-based fabric filter, and is directly detected by the MXene acetone sensor through the openings of the detection circuit board and the openings of the packaging layer, without the need for other pretreatment.

[0018] The beneficial effects of the embodiments of the present invention are as follows: The present invention provides a wearable exhaled breath acetone detection method and device based on MXene, which can realize continuous and real-time wearable exhaled breath analysis. The MXene acetone sensor designed based on MXene nanomaterials has excellent sensitivity and low detection limit, and the combination with the MXene-based fabric filter improves the selectivity and anti-interference ability of exhaled breath acetone detection. The exhaled breath acetone detection tag constructed based on flexible electronic technology is combined with a disposable mask to provide a wearable detection platform for exhaled breath analysis without pretreatment. Using the Bluetooth in the MXene smart mask for wireless communication, it is possible to further realize the continuous real-time display of the respiratory curve on the mobile terminal, as well as the monitoring and analysis of physiological and biochemical parameters such as exhaled breath acetone concentration and respiratory rate.

[0019] Compared with desktop exhaled breath analysis instruments such as gas chromatography-mass spectrometry and selective ion flow tube mass spectrometry, the MXene smart mask of the present invention does not require manual operation, is flexible and convenient to use, and is not restricted by the user and the scene. Compared with similar portable exhaled breath analysis technologies, the present invention realizes wearable exhaled breath acetone detection, which is more convenient to use and can achieve continuous and real-time exhaled breath acetone analysis. The wearing feel of the MXene smart mask is similar to that of an ordinary disposable mask. While achieving daily health protection, it can further reflect the changes in exhaled breath acetone concentration caused by lipid metabolic activities such as diet and exercise in daily life. Based on the above advantages, the device and method of the present invention can be widely used in daily metabolic health management. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1 This is a schematic diagram of the outer side of the MXene smart mask provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the inside of the MXene smart mask provided by an embodiment of the present invention;

[0023] Figure 3 This is a hierarchical structure diagram of an exhaled breath acetone detection label provided by an embodiment of the present invention;

[0024] Figure 4 is an assembly diagram of an exhaled breath acetone detection label provided by an embodiment of the present invention;

[0025] Figure 5 This is a modified image of a MXene acetone sensor provided in an embodiment of the present invention;

[0026] Figure 6 is a structural diagram of a MXene-based fabric filter provided in an embodiment of the present invention;

[0027] Figure 7 This is a modified diagram of a MXene-based fabric filter provided by an embodiment of the present invention;

[0028] Figure 8 is a functional module diagram of a detection circuit provided by an embodiment of the present invention;

[0029] Fig. 9 is an acetone detection response diagram of an acetone detection device provided by an embodiment of the present invention;

[0030] Fig.10 is a linear fitting diagram of acetone detection of an acetone detection device provided by an embodiment of the present invention;

[0031] Fig.11 is an acetone detection repeatability response diagram of an acetone detection device provided by an embodiment of the present invention;

[0032] Fig.12 is an acetone detection stability response diagram of an acetone detection device provided by an embodiment of the present invention;

[0033] Fig.13 is a humidity filtration performance diagram of an acetone detection device provided by an embodiment of the present invention;

[0034] Fig.14 This is a graph of ethanol filtration performance of an acetone detection device provided by an embodiment of the present invention;

[0035] Fig.15 This is a graph of ammonia filtration performance of an acetone detection device provided by an embodiment of the present invention;

[0036] Fig.16 is an acetone filtration performance diagram of an acetone detection device provided by an embodiment of the present invention;

[0037] Fig.17 is an acetone detection selectivity diagram of an acetone detection device provided by an embodiment of the present invention;

[0038] Fig.18 This is a schematic diagram of an implementation scheme of a MXene smart mask provided in an embodiment of the present invention;

[0039] Fig.19 This is a correlation diagram between the exhaled breath acetone detection result and the blood ketone detection result of the MXene smart mask provided in an embodiment of the present invention;

[0040] In the figure: disposable mask 1, breathing valve 2, breathing valve housing 3, exhaled breath acetone detection label 4, MXene-based fabric filter 5, MXene acetone sensor 41, flexible detection circuit board 42, detection circuit board window 421, polydimethylsiloxane encapsulation layer 43, encapsulation layer window 431, light-emitting diode circuit board 44, light-emitting diode substrate 441, light-emitting diode 442, detection circuit substrate 422, detection circuit 423, diode circuit connection pad 424, sensor connection pad 425, sensor substrate 411, gold interdigital electrode 412, MXene nanosensing layer 413, titanium dioxide nanoparticles 414, short peptide molecules 415, active desiccant 51, platinum nanoparticle-loaded MXene fabric 52, MXene smart mask 11, mobile terminal 12, real-time breathing curve display function area 13, breathing result analysis function area 14. DETAILED DESCRIPTION

[0041] The embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings, but the present invention is not limited thereto. Based on any embodiment expanded from the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field, without making creative work, belong to the scope of protection of the present invention. The same symbols in the drawings represent the same or functionally similar elements. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0042] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the specific implementation modes below. Those skilled in the art should understand that the present disclosure can also be implemented without certain specific details. Some methods and means well known to those skilled in the art and the use of components are not described in detail in order to highlight the main purpose of the present disclosure.

[0043] The embodiment of the present invention provides a wearable exhaled breath acetone detection device based on MXene, which mainly includes: an exhaled breath acetone detection tag 4, wherein the exhaled breath acetone detection tag 4 is used to detect the acetone concentration in the exhaled breath.

[0044] Figure 3The hierarchical structure diagram of the exhaled breath acetone detection label 4 is shown. The exhaled breath acetone detection label 4 is assembled from top to bottom by a light-emitting diode circuit board 44, a polydimethylsiloxane encapsulation layer 43, a flexible detection circuit board 42 and a MXene acetone sensor 41. Among them, the polydimethylsiloxane encapsulation layer 43 performs top-level encapsulation of the flexible detection circuit board 42 by a solution thermal curing method, and the polydimethylsiloxane encapsulation layer 43 and the flexible detection circuit board 42 are processed by laser cutting. The size of the encapsulation layer window 431 and the detection circuit board window 421 is consistent with the MXene acetone sensor 41. This design is conducive to the direct contact between the MXene acetone sensor 41 located at the bottom of the exhaled breath acetone detection label 4 and the exhaled breath to realize the detection of exhaled breath acetone. The polydimethylsiloxane encapsulation layer 43 plays a protective role for the flexible detection circuit board 42, and at the same time acts as a spacer to fix the working distance between the light-emitting diode circuit board 44 and the MXene acetone sensor 41. By adjusting the thickness of the polydimethylsiloxane encapsulation layer 43, different illumination working distances can be controlled. The illumination working distance is related to the sensor receiving power density, and in this embodiment is 1.5 mm.

[0045] Figure 4 The assembly diagram of the exhaled breath acetone detection tag 4 is shown. The flexible detection circuit board 42 is composed of a detection circuit substrate 422, a detection circuit 423, a diode circuit connection pad 424 and a sensor connection pad 425. The light-emitting diode 442 is fixed on the light-emitting diode substrate 441, and is further assembled on the polydimethylsiloxane encapsulation layer 43. It is aligned with the MXene acetone sensor 41 through the encapsulation layer window 431 and the detection circuit board window 421 to fix the illumination working distance, and is welded to the diode circuit connection pad 424 through low-temperature soldering to achieve electrical connection with the flexible detection circuit board 42. The MXene acetone sensor 41 includes a sensor substrate 411 and a gold interdigital electrode 412, and is welded to the sensor connection pad 425 through low-temperature soldering to achieve electrical connection with the exhaled breath acetone detection tag 4.

[0046] like Figure 5As shown, the MXene acetone sensor 41 is modified with a MXene nanosensing layer 413, titanium dioxide nanoparticles 414 and short peptide molecules 415 on a gold interdigitated electrode 412. The short peptide molecules 415 can improve the detection performance. In the present invention, short peptide molecules such as phenylalanine-serine-lysine, methionine-cysteine-histidine, tryptophan-alanine-leucine, etc. can be used, but not limited to this. The MXene nanosensing layer 413 is prepared by etching ceramic phase titanium aluminum carbon with hydrochloric acid / lithium fluoride solution. Specifically, 2 parts by mass of lithium fluoride are dissolved in 40 parts by volume of concentrated hydrochloric acid (mass fraction of 36% to 38%), stirred at room temperature for 30 minutes, and an etching solution is prepared. Then 2 parts by mass of ceramic phase titanium aluminum carbon powder are slowly added to the solution, and the reaction is stirred at 40°C for 24 hours. After the reaction is completed, the mixed solution is centrifuged at 3500 rpm, the supernatant is removed and washed with deionized water, mechanically oscillated using a vortex generator, and centrifuged again at 3500 rpm, and the supernatant is removed again. Repeat the above steps until the black precipitate swells and is clearly stratified. The black precipitate is collected and dispersed with deionized water, and the MXene multilayer film is further peeled off using an ultrasonic method to obtain a MXene nanosensing layer 413. The obtained MXene nanosensing layer 413 is configured to a suitable concentration, mixed with 3% mass fraction hydrogen peroxide in different volume ratios, and heated in a water bath at 80°C for 5 minutes to prepare a MXene nanosensing layer 413 loaded with titanium dioxide nanoparticles 414 at different concentrations. The above materials were mixed and dissolved with the short peptide molecule 415 (phenylalanine-serine-lysine) at a mass ratio of 1:2, stirred at room temperature for 5 minutes, and a uniformly dispersed solution was obtained. Subsequently, 0.005 parts by mass of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine were added, respectively, and stirred at 100°C for 3 hours. The obtained solution was centrifuged at a speed of 8000 rpm, and the sediment was rinsed with deionized water and redispersed into a suitable concentration to obtain a MXene nanosensing layer co-modified with titanium dioxide nanoparticles and short peptides, which was sprayed on the plasma-cleaned sensor substrate 411 and the gold interdigitated electrode 412 using a spray gun, and finally the MXene acetone sensor 41 was obtained after drying.

[0047] The detection system functional modules of the device are as follows: Figure 8As shown. The detection circuit 423 is mainly composed of a microcontroller, a constant current source, a low-pass network, an analog-to-digital converter, Bluetooth, a field effect tube, a battery and a power management circuit, and peripheral resistors and capacitors. Among them, the microcontroller realizes signal modulation, data processing and other functions, specifically, the constant current source provides a reference voltage Vref, obtains the analog-to-digital converter sampling signal through buses such as I2C, transmits data with Bluetooth, and controls the on-off of the field effect tube, etc. The constant current source outputs a constant test current Imeasure according to the reference voltage Vref, generates a voltage signal after passing through the MXene acetone sensor 41, and removes the power frequency noise interference through the low-pass network filtering, and finally is converted by the analog-to-digital converter to generate a sampling signal. The microprocessor generates a control signal to adjust the on-off of the field effect tube, realizes the switch of the light-emitting diode 442, and controls the light irradiation time of the MXene acetone sensor 41. Bluetooth transmits signals with the mobile terminal through wireless communication, and performs data processing and display at the mobile terminal. The system is powered by a battery and a power management module to provide a power supply voltage Vcc to drive the detection circuit 423. In order to realize compact and miniaturized circuit design, the detection circuit 423 may adopt micro-low-power chips, including but not limited to MSP430FR2632 microprocessor chip, AD8605 operational amplifier chip, ADS1115 analog-to-digital conversion chip, etc.

[0048] The device of the present invention can monitor the exhaled breath acetone concentration of 0.5-50ppm in real time and is calibrated before use. In the calibration experiment, standard acetone gas (100ppm) is mixed with standard air to obtain acetone gas of different concentrations. The standard acetone gas is obtained by completely volatilizing anhydrous acetone in standard air.

[0049] Since the MXene acetone sensor 41 has irreversible acetone adsorption, in order to achieve good repeatability and quantitative analysis of acetone sensing detection, the present invention introduces a light-emitting diode 442 to irradiate the MXene acetone sensor 41. Since the photoelectric response heterogeneous interface composed of titanium dioxide nanoparticles 414 and MXene nanosensing layer 413 in the MXene acetone sensor 41 can generate photogenerated carriers under light irradiation conditions to improve acetone desorption, the light-emitting diode 442 is kept turned on during acetone detection to correct the response of the MXene acetone sensor 41.

[0050] like Fig. 9 As shown, when acetone gas is introduced, the MXene acetone sensor 41 produces a positive normalized resistance response, indicating that the sensor resistance increases with the introduction of acetone. When air is introduced again, the acetone response returns to the baseline value, indicating that the acetone response under light irradiation conditions is completely reversible, and the response value increases successively with the increase of acetone concentration. In addition, Fig. 9This indicates that the MXene acetone sensor 41 has a faster acetone response and recovery speed, which is beneficial to further shorten the exhaled breath analysis time. The same batch of MXene acetone sensors 41 were subjected to three independent repeated experiments, and the obtained results were plotted in a scatter plot and piecewise linear fitting was used. Fig.10 As shown, the acetone response shows linear correlation in the concentration ranges of 0.5-2ppm and 2-50ppm, respectively. In the range of 0.5-2ppm, the linear correlation coefficient R 2 The linear correlation coefficient R in the range of 2-50ppm is 0.98, the sensitivity is 0.672% / ppm; 2 The results of independent repeated tests have good consistency, as shown in Fig.10 Smaller error bars.

[0051] This embodiment tests the detection repeatability and long-term stability of the MXene acetone sensor 41. Figure 11-12 As shown, the MXene acetone sensor 41 exhibits good reversibility in the response-recovery of 5ppm acetone for multiple consecutive cycles, and the response amplitude remains consistent. The stability test for 15 consecutive days shows that the MXene acetone sensor 41 has good long-term stability and can be used for long-term exhaled breath acetone detection with a small response attenuation.

[0052] In view of typical interferences such as humidity, exhaled ethanol, and ammonia in exhaled breath, as a preferred embodiment, the present invention proposes a MXene-based fabric filter 5 capable of suppressing respiratory interference. The MXene-based fabric filter 5 is composed of a platinum nanoparticle-loaded MXene fabric 52 and an active desiccant 51, such as Figure 6 As shown. The active desiccant 51 can be a granular desiccant that is harmless to the human body, including but not limited to activated alumina, color-changing silica gel, etc. The platinum nanoparticle-loaded MXene fabric 52 is prepared by a two-step solution treatment method, such as Figure 7As shown. First, the white cotton fabric washed with deionized water and dried was immersed in a 5 mg / mL MXene solution and deposited for 30 minutes. MXene is used to form a hydrogen bond network with the abundant oxygen-containing functional groups on the surface of the cotton fabric to achieve stable electrostatic adsorption of MXene on the cotton fabric. The unadsorbed MXene was rinsed with deionized water and dried. Repeat the above steps until a black MXene fabric was obtained. The obtained MXene fabric was immersed in a 3.86 nM chloroplatinic acid solution and reacted for 30 minutes. The chemically active surface of MXene was used to achieve in-situ reduction of platinum nanoparticles to prepare a platinum nanoparticle-loaded MXene fabric 52. The active desiccant 51 was filled between the platinum nanoparticle-loaded MXene fabric 52, and the platinum nanoparticle-loaded MXene fabric 52 was encapsulated and bonded with polydimethylsiloxane glue with good air permeability to obtain a MXene-based fabric filter 5.

[0053] The present invention calibrates its interference filtering performance. Figure 13-16 As shown, the experiment used simulated exhaled air (5% carbon dioxide, 79% nitrogen, 16% oxygen) mixed with 10ppm ammonia, ethanol, acetone and 90% relative humidity to obtain unfiltered standard gas. The unfiltered interferent response was tested using a MXene acetone sensor 41, and the humidity was calibrated using a commercial hygrometer, and the concentrations of ammonia, ethanol, and acetone were calibrated using a meteorological chromatograph. At the same time, the simulated exhaled air containing interferents was passed through a MXene-based fabric filter 5, and the filtered simulated exhaled air was tested for response by a MXene acetone sensor 41, and the exhaust gas was collected with an air bag and the humidity was calibrated again using a commercial hygrometer, and the concentrations of ammonia, ethanol, and acetone were calibrated using a meteorological chromatograph. Figure 13-16 It shows that the MXene-based fabric filter 5 has a good filtering effect on ammonia, ethanol, and humidity, and has a certain filtering effect on acetone, but the MXene acetone sensor 41 still maintains a high acetone response. Therefore, the MXene-based fabric filter 5 can improve the selectivity of exhaled breath acetone detection.

[0054] Furthermore, the device of the present invention can achieve selective exhaled breath acetone detection in the presence of interfering substances. Fig.17 As shown, the experiment was configured with 90% RH humidity simulated exhaled breath mixed with 10 ppm acetone, ammonia, ethanol, hexane, and isoprene respectively. The test results showed that the device of the present invention produced the highest response to acetone, and had obvious inhibition on both polar and non-polar exhaled breath interferents. From the aspect of selectivity, it can meet the demand for acetone detection in complex exhaled breath environments.

[0055] In order to achieve stable detection, as a preferred embodiment, the device also includes a disposable mask 1, a breathing valve 2, and a breathing valve housing 3, forming a MXene smart mask 11, wherein the exhaled breath acetone detection label 4 is fixed between the breathing valve 2 and the breathing valve housing 3 on the outside of the disposable mask 1, and is used to detect the acetone concentration in the exhaled breath. The MXene-based fabric filter 5 is fixed on the breathing valve 2 on the inside of the disposable mask 1, and is used to filter the exhaled air passing through the breathing valve 2, such as Figure 1-2 shown.

[0056] Fig.18 It is a schematic diagram of an implementation of the MXene smart mask 11 provided in an embodiment of the present invention. The MXene-based fabric filter 5 is mounted on the inner surface of the disposable mask 1 close to the breathing valve 2, and the exhaled breath acetone detection label 4 is mounted between the breathing valve 2 and the breathing valve housing 3 on the outside of the disposable mask 1. Bluetooth wireless transmission is used to realize data communication and subsequent data display processing between the MXene smart mask 11 for exhaled breath acetone detection and the mobile terminal 12. The exhaled air is filtered through the MXene-based fabric filter 5, and is directly detected by the MXene acetone sensor 41 through the detection circuit board window 421 and the packaging layer window 431, without other preprocessing. The mobile terminal 12 draws a continuous real-time breathing curve based on the received data, and displays the exhaled breath rhythm and exhaled breath acetone concentration changes caused by respiratory activity in the real-time breathing curve display function area 13, and the breathing result analysis function area 14 displays the calculated exhaled breath acetone concentration and the breathing rate per minute.

[0057] Furthermore, this embodiment recruited 5 volunteers to conduct in vivo breathing test verification on the MXene smart mask 11 described in the present invention, and detected the changes in blood ketone concentrations of the 5 volunteers as a standard reference for changes in exhaled breath acetone concentrations. Blood ketone test is a commonly used ketone body test method in clinical practice, and it is also a common reference value for exhaled breath acetone detection. During the experiment, the volunteers followed the guidance of the experimenters, wore the MXene smart mask 11 for exhaled breath acetone detection, and conducted an exhaled breath acetone test within 5 minutes, while collecting fingertip blood and performing blood ketone level detection. Before blood collection, use alcohol cotton pads to disinfect the fingertips, use a blood collection pen and a disposable minimally invasive blood collection needle when collecting blood, and use standard biochemical test paper to detect blood ketone levels as a reference. One exhaled breath acetone test and one blood ketone level test are counted as one standard test. Among them, two volunteers participated in the diet test, consuming a balanced diet, a ketogenic diet, and a high-carb diet for three days. Standard tests were performed at 5:30 pm and 8:30 pm on the first day, and every 3 hours from 8:30 am to 8:30 pm on the second day. Standard tests were performed every 3 hours from 8:30 am to 5:30 pm on the third day, for a total of 11 standard tests per person. Another three volunteers participated in the exercise test, doing two and a half hours of cycling on weekdays, for a total of one hour of exercise. The experiment controlled the subjects' exercise load and monitored cardiac output as a reference for exercise intensity. Afterwards, the volunteers needed to sit and rest for a total of two hours, and the experiment lasted a total of three hours. During the experiment, standard tests were performed at 0, 30, 90, 120, and 180 minutes, for a total of 5 standard tests per person.

[0058] like Fig.19 As shown, the MXene smart mask 11 provided in the embodiment of the present invention is used for exhaled breath acetone detection, and the obtained results are correlated with the blood ketone levels of volunteers. The Pearson correlation coefficient between exhaled breath acetone and blood ketone obtained by linear regression is 0.911, which proves that the MXene smart mask 11 can be used for reliable exhaled breath acetone detection.

[0059] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Without making creative work, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims

1. A wearable exhaled breath acetone detection device based on MXene, characterized in that: It includes: An exhaled breath acetone detection label (4); the exhaled breath acetone detection label (4) comprises a MXene acetone sensor (41), a flexible detection circuit board (42), a polydimethylsiloxane encapsulation layer (43) for encapsulating the flexible detection circuit board (42), and a light-emitting diode circuit board (44) assembled in sequence from bottom to top, wherein the light-emitting diode circuit board (44) comprises a light-emitting diode substrate (441) and a light-emitting diode (442) fixed to the light-emitting diode substrate (441), and the flexible detection circuit board (42) and the polydimethylsiloxane encapsulation layer (43) are provided with windows so that the light-emitting diode (442) faces the MXene acetone sensor (41); The diode circuit board (44), the MXene acetone sensor (41) and the flexible detection circuit board (42) are electrically connected; wherein the MXene acetone sensor (41) is used to detect the concentration of acetone in the exhaled breath and convert it into an electrical signal, and the flexible detection circuit board (42) is used to obtain and process the electrical signal of the MXene acetone sensor (41); the MXene acetone sensor (41) comprises a sensor substrate (411), a gold interdigital electrode (412) and a MXene nanosensing layer (413) assembled in sequence from bottom to top, and the surface of the MXene nanosensing layer (413) is modified with titanium dioxide nanoparticles (414) and short peptide molecules (415).

2. The device according to claim 1, characterized in that The MXene nanosensing layer (413) is prepared by mixing 2 parts by mass of ceramic phase titanium aluminum carbon powder with 2 parts by mass of lithium fluoride and dissolving them in 40 parts by volume of concentrated hydrochloric acid, etching at 40° C. for 24 hours, washing the precipitate with deionized water, and then spraying the MXene nanosensing layer on the surface of the gold interdigital electrode (412) using a vortex generator to assist ultrasonic mechanical stripping.

3. The device according to claim 1, characterized in that The titanium dioxide nanoparticles (414) are modified by the following method: a MXene nanosensing layer (413) is mixed with a 3% by mass hydrogen peroxide solution, and the mixture is heated in a water bath at 80° C. The titanium dioxide nanoparticles (414) are in-situ grown on the MXene nanosensing layer (413).

4. The device according to claim 1, characterized in that The short peptide molecule (415) is modified by the following method: the short peptide molecule (415) is mixed and dissolved with a MXene nanosensing layer (413) on which titanium dioxide nanoparticles (414) are grown in situ at a mass ratio of 1:2, and 0.005 mass parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine catalyst are added respectively, and the mixture is stirred at 100° C. for 3 hours to react to obtain a MXene nanosensing layer (413) co-modified with titanium dioxide nanoparticles (414) and the short peptide molecule (415).

5. The device according to claim 1, characterized in that It also includes a MXene-based fabric filter (5) for filtering exhaled air; the MXene-based fabric filter (5) is composed of a platinum nanoparticle-loaded MXene fabric (52) and an active desiccant (51) wrapped in the platinum nanoparticle-loaded MXene fabric (52); the platinum nanoparticle-loaded MXene fabric (52) is obtained by electrostatically adsorbing MXene on the surface of cotton fabric, and then in situ reducing the loaded platinum nanoparticles on the surface of MXene in a chloroplatinic acid solution.

6. The device according to claim 5, characterized in that The platinum nanoparticle-loaded MXene fabric (52) is specifically prepared by the following method: a white cotton fabric washed with deionized water and dried is immersed in a 5 mg / mL MXene solution, deposited for 30 minutes, repeatedly washed and dried, and then immersed in a 3.86 mM chloroplatinic acid solution, reacted for 30 minutes, and the in-situ reduction of platinum nanoparticles is achieved by utilizing the chemically active surface of MXene.

7. The device according to claim 1, characterized in that The flexible detection circuit board (42) is composed of a detection circuit substrate (422), a detection circuit (423), a diode circuit connection pad (424) and a sensor connection pad (425). The detection circuit substrate (422) is composed of a polyimide film. The detection circuit (423) mainly includes a micro low-power chip and peripheral resistors and capacitors, and is used to obtain and process the electrical signal of the MXene acetone sensor (41). The light-emitting diode circuit board (44) and the MXene acetone sensor (41) are respectively welded to the diode circuit connection pad (424) and the sensor connection pad (425) by low-temperature soldering, so as to realize the electrical connection between the diode circuit board (44), the MXene acetone sensor (41) and the flexible detection circuit board (42).

8. The device according to claim 7, characterized in that The detection circuit (423) is composed of a microcontroller, a constant current source, an analog-to-digital converter, Bluetooth, a low-pass network, a field effect transistor, a light-emitting diode, a battery and a power management circuit, and peripheral resistors and capacitors.

9. The device according to any one of claims 1 to 8, characterized in that: The invention also comprises a disposable mask (1), a breathing valve (2) fixed on the disposable mask (1), and a breathing valve housing (3); the exhaled air acetone detection label (4) is fixed between the breathing valve (2) and the breathing valve housing (3) on the outside of the disposable mask (1); and a MXene-based fabric filter (5) is fixed on the breathing valve (2) on the inside of the disposable mask (1) to filter the exhaled air passing through the breathing valve (2).

10. A method for detecting acetone in exhaled breath based on MXene, characterized in that: Specifically: The acetone concentration in the exhaled breath is obtained using the device according to any one of claims 1 to 9, and the light emitting diode (442) is kept turned on during the acetone detection.

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