CN115486834A - A wearable exhaled acetone detection method and device based on MXene - Google Patents

Abstract

The invention discloses a wearable exhaled breath acetone detection method and device based on MXene. The device includes an exhaled breath acetone detection label. The exhaled breath acetone detection label is formed by assembling an MXene acetone sensor, a flexible detection circuit board, a polydimethylsiloxane packaging layer and a light-emitting diode circuit board and is used for detecting the concentration of acetone in exhaled breath. The invention utilizes the wireless Bluetooth between the MXene device and the mobile terminal to carry out data interaction, realizes continuous and real-time monitoring of the dynamic change of the acetone concentration of the exhaled breath, reflects the intensity of lipid metabolism activities such as diet and fat burning movement and the like, and further realizes daily metabolic health management. The method provides a wearable detection platform for exhaled breath analysis, and has the advantages of non-invasiveness, continuity, real-time performance, simplicity in operation, rapidness in detection and the like.

Description

A wearable exhaled acetone detection method and device based on MXene

technical field

The invention relates to a detection technology of acetone in exhaled gas, in particular to a wearable method and device for detecting acetone in exhaled gas based on MXene.

Background technique

Exhaled acetone is an important product of lipid metabolism and is considered to be one of the most attractive targets for monitoring lipid metabolism. Clinical evidence shows that acetone is produced by a series of oxidations of fatty acids in the mitochondria of the liver and is mainly excreted by exhaled air. Therefore, exhaled acetone has a clear source and pathway of metabolism, which can reflect the lipid metabolism related to daily activities such as dietary habits and physical exercise. Studies have shown that exhaled acetone concentrations in healthy subjects range from hundreds of ppb (parts per billion) to 0.9 ppm (parts per million) after fasting, a ketogenic diet, or aerobic exercise Can rise significantly to tens or hundreds of ppm. Therefore, the detection of acetone in exhaled breath has great potential in guiding weight loss, evaluating exercise tolerance, or guiding the treatment of ketoacidosis, and is expected to be applied in 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 has less burden on the tested object, so it has great prospects in medical diagnosis and personalized health care.

At present, standard exhaled breath testing 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 inspections, but are difficult to be widely used in daily personal metabolic health monitor. Therefore, the development of portable and wearable miniaturized exhaled breath detection solutions can be used as an important supplement to clinical standard exhaled breath detection. In recent years, an emerging family of two-dimensional transition metal carbide and nitride nanomaterials (MXenes) has received great attention in sensor development, mainly due to its metallic conductivity, highly chemically active surface, and high signal-to-noise ratio. A series of excellent characteristics. Therefore, MXenes are uniquely attractive for 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, aiming at the detection application bottlenecks such as high humidity, multiple interferers, and sensor response drift in exhaled breath detection, based on the MXene nanomaterial platform and disposable masks, a set of exhaled breath filters integrating interferent filtering, sensor detection, response correction and wireless data transmission will be developed. The gas acetone detection MXene smart mask device and method are of great significance for promoting wearable breath analysis and daily lipid metabolism management.

Contents of the invention

The purpose of the present invention is to address the deficiencies of the prior art and products, to provide a wearable exhaled acetone detection method and device based on MXene, so as to realize the continuous real-time wearable detection of exhaled acetone in daily life, reflecting the relationship with lipid metabolism Related diet, exercise and health management.

The purpose of the present invention is achieved through the following technical solutions:

A wearable exhaled acetone detection device based on MXene, which includes: an exhaled acetone detection label; the exhaled acetone detection label includes an MXene acetone sensor assembled sequentially from bottom to top, a flexible detection circuit board, and a flexible detection circuit board for packaging The polydimethylsiloxane encapsulation layer of the detection circuit board and the light-emitting diode circuit board, the light-emitting diode circuit board is composed of a light-emitting diode base and a light-emitting diode fixed on the light-emitting diode base, the flexible detection circuit board and polydimethylsiloxane The siloxane-based encapsulation layer is provided with a window, so that the light-emitting diode is facing the MXene acetone sensor; the diode circuit board, the MXene acetone sensor are electrically connected to the flexible detection circuit board; wherein, the MXene acetone sensor is used to detect the concentration of acetone in the exhaled air And convert it into an electrical signal, the flexible detection circuit board is used to acquire and process the electrical signal of the MXene acetone sensor; the MXene acetone sensor includes a sensor substrate, a gold interdigitated electrode and an MXene nano-sensing layer assembled sequentially from bottom to top, the The surface of the MXene nano sensing layer is modified with titanium dioxide nanoparticles and short peptide molecules.

Further, the MXene nano-sensing layer is composed of 2 parts by mass of ceramic phase titanium aluminum carbon powder mixed with 2 parts by mass of lithium fluoride dissolved in 40 parts by volume of concentrated hydrochloric acid, etched at 40 ° C for 24 hours, passed through deionized water Clean the precipitate, use the vortex generator to assist ultrasonic mechanical peeling, and then spray it on the surface of the gold interdigitated electrode.

Further, the titanium dioxide nanoparticles are modified by the following method: the MXene nano-sensing layer is mixed with a 3% mass fraction hydrogen peroxide solution, prepared by heating in a water bath at 80°C, and the titanium dioxide nanoparticles are grown on the MXene nano-sensing layer in situ superior.

Further, the short peptide molecule is modified by the following method: mix and dissolve with the MXene nano-sensing layer of titanium dioxide nanoparticles grown in situ at a mass ratio of 1:2, and add 0.005 parts by mass of 1-ethyl-(3- Dimethylaminopropyl) carbodiimide and 4-dimethylaminopyridine catalysts were stirred at 100°C for 3 hours to obtain a MXene nanosensing layer co-modified with titanium dioxide nanoparticles and short peptide molecules.

Further, it also includes an MXene-based fabric filter for filtering exhaled air; the MXene-based fabric filter consists of a platinum nanoparticle-loaded MXene fabric and an active desiccant wrapped in a platinum nanoparticle-loaded MXene fabric, so The platinum nanoparticle-loaded MXene fabric is obtained by electrostatically adsorbing MXene on the surface of cotton fabric, and then reducing the loaded platinum nanoparticles on the MXene surface in situ in a chloroplatinic acid solution.

Further, the platinum nanoparticle-loaded MXene fabric is specifically prepared by the following method: the white cotton fabric washed and dried with deionized water is soaked in a 5 mg/mL MXene solution, deposited for 30 minutes, washed and dried repeatedly, soaked in 3.86 In mM chloroplatinic acid solution for 30 min, the chemically active surface of MXene was used to realize the in situ reduction of platinum nanoparticles.

Further, the flexible detection circuit board is composed of a detection circuit base, a detection circuit, a diode circuit connection pad and a sensor connection pad, the detection circuit base is composed of a polyimide film, and the detection circuit mainly includes a micro low-power chip, The external resistor and capacitor 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 on the diode circuit connection pad and the sensor connection pad through low-temperature soldering tin to realize the diode circuit board and MXene acetone sensor. Electrical connection of the acetone sensor to the flex detection circuit board.

Further, 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.

Further, it also includes a disposable mask, a breathing valve and a breathing valve shell fixed on the disposable mask, and the exhaled acetone detection label is fixed between the breathing valve and the breathing valve shell on the outside of the disposable mask, and the fabric based on MXene The filter is fixed on the breathing valve inside the disposable mask to filter the exhaled air passing through the breathing valve.

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

The acetone concentration in the exhaled breath is obtained by using the above-mentioned device, and the light-emitting diode is kept turned on during the acetone detection period.

In the detection method of the present invention, the exhaled air is filtered through the MXene-based fabric filter, and is directly detected by the MXene acetone sensor through the window opening of the detection circuit board and the packaging layer without other pretreatment.

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 acetone detection. The combination of exhaled acetone detection label based on flexible electronic technology and disposable masks provides a wearable detection platform for exhaled breath analysis without pretreatment. Using the Bluetooth in the MXene smart mask for wireless communication can 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 acetone concentration and respiratory rate in the exhaled breath.

Compared with desktop exhaled gas 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 users and scenarios. Compared with similar portable exhaled gas analysis technologies, the present invention realizes wearable exhaled acetone detection, is more convenient to use, and can realize continuous and real-time exhaled acetone analysis. The MXene smart mask has a similar wearing feel to ordinary disposable masks. While achieving daily health protection, it can further reflect the changes in exhaled acetone concentration caused by lipid metabolism activities such as diet and exercise in daily life. According to the above advantages, the device and method of the present invention can be widely used in daily metabolic health management.

Description of drawings

The drawings described here are used to provide a further understanding of the application and constitute a part of the application. The schematic embodiments and descriptions of the application are used to explain the application and do not constitute an improper limitation to the application. In the attached picture:

Fig. 1 is a schematic diagram of the outside of the MXene smart mask provided by the embodiment of the invention;

Fig. 2 is a schematic diagram of the inside of the MXene smart mask provided by the embodiment of the present invention;

Fig. 3 is a hierarchical structure diagram of an exhaled acetone detection label provided by an embodiment of the present invention;

Fig. 4 is an assembly diagram of an exhaled acetone detection label provided by an embodiment of the present invention;

Fig. 5 is the modified figure of the MXene acetone sensor provided by the embodiment of the invention;

Fig. 6 is the structural diagram of the fabric filter based on MXene provided by the embodiment of the present invention;

Fig. 7 is the modified figure of the fabric filter based on MXene provided by the embodiment of the present invention;

Fig. 8 is a functional block diagram of a detection circuit provided by an embodiment of the present invention;

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

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

Fig. 11 is a response diagram of acetone detection repeatability of the acetone detection device provided by the embodiment of the present invention;

Fig. 12 is a response diagram of acetone detection stability of the acetone detection device provided by the embodiment of the present invention;

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

Fig. 14 is an ethanol filtration performance diagram of the acetone detection device provided by the embodiment of the present invention;

Fig. 15 is a diagram of the ammonia filtration performance of the acetone detection device provided by the embodiment of the present invention;

Figure 16 is a diagram of the acetone filtration performance of the acetone detection device provided by the embodiment of the present invention;

Figure 17 is a selectivity diagram of acetone detection by the acetone detection device provided by the embodiment of the present invention;

Figure 18 is a schematic diagram of the implementation of the MXene smart mask provided by the embodiment of the present invention;

Figure 19 is a correlation diagram between the detection results of exhaled acetone and blood ketone detection by the MXene smart mask provided by the embodiment of the present invention;

In the figure: disposable mask 1, breathing valve 2, breathing valve housing 3, exhaled 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 opening 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 interdigitated electrode 412, MXene nano-sensing layer 413, titanium dioxide nanoparticles 414, short peptide molecules 415, active desiccant 51, platinum nanoparticles loaded MXene fabric 52, MXene smart mask 11, mobile Terminal 12, real-time respiratory curve display functional area 13, respiratory result analysis functional area 14.

detailed description

Embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings, but do not limit the present invention. Based on any embodiment extended from the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work shall fall within the protection scope of the present invention. Like numbers in the figures indicate identical or functionally similar elements. While various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that the present disclosure can also be implemented without certain specific details. The methods and means well known to those in the art, and the use of components are not described in detail in order to highlight the gist of the present disclosure.

An embodiment of the present invention provides a wearable exhaled acetone detection device based on MXene, which mainly includes: an exhaled acetone detection label 4, and the exhaled acetone detection label 4 is used to detect the concentration of acetone in the exhaled air.

Figure 3 shows the hierarchical structure diagram of the exhaled acetone detection label 4. The 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 an MXene acetone sensor 41 . Among them, the polydimethylsiloxane encapsulation layer 43 encapsulates the flexible detection circuit board 42 on the top layer by solution thermal curing, and uses laser cutting to encapsulate the polydimethylsiloxane encapsulation layer 43 and the flexible detection circuit board 42. Window processing, the size of the window 431 in the packaging layer and the window 421 in the detection circuit board are consistent with the size of 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 acetone detection label 4 and the exhaled gas, so as to realize the exhaled acetone detection. The polydimethylsiloxane encapsulation layer 43 protects the flexible detection circuit board 42 and serves as a spacer to fix the working distance between the LED circuit board 44 and the MXene acetone sensor 41 . By adjusting the thickness of the polydimethylsiloxane encapsulation layer 43 , different working distances of light can be controlled. The working distance of illumination is related to the received power density of the sensor, which is 1.5 mm in this embodiment.

FIG. 4 shows an assembly diagram of the breath acetone detection label 4 . 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, further assembled on the polydimethylsiloxane encapsulation layer 43, and aligns with the MXene acetone sensor 41 through the encapsulation layer opening 431 and the detection circuit board opening 421 to fix the light. Working distance, and through low-temperature soldering and diode circuit connection pad 424 welding, and the electrical connection with the flexible detection circuit board 42 . The MXene acetone sensor 41 includes a sensor substrate 411 and a gold interdigitated electrode 412, and is welded to the sensor connection pad 425 by low-temperature soldering to realize the electrical connection with the exhaled acetone detection label 4 .

As shown in Figure 5, the MXene acetone sensor 41 has modified the MXene nano-sensing layer 413, titanium dioxide nanoparticles 414 and short peptide molecules 415 on the gold interdigitated electrode 412, and 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 are not limited thereto. The MXene nano-sensing 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 was dissolved in 40 parts by volume of concentrated hydrochloric acid (36%-38% by mass), and stirred at room temperature for 30 minutes to prepare an etching solution. Then slowly add 2 parts by mass of ceramic phase titanium aluminum carbon powder into the solution, and stir and react at 40° C. for 24 hours. After the reaction is completed, take the mixed solution and centrifuge at a speed of 3500 rpm, remove the supernatant, wash with deionized water, use a vortex generator for mechanical oscillation, and centrifuge again at a speed of 3500 rpm, and remove the supernatant again . Repeat the above steps until the black precipitate swells and visibly separates. The black precipitate was collected and dispersed with deionized water, and the MXene multilayer film was further peeled off by ultrasonic method to obtain the MXene nano-sensing layer 413 . The obtained MXene nano-sensing 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 MXene nano-particles 414 loaded with different concentrations of titanium dioxide nanoparticles. Sensing layer 413 . Mix and dissolve the above materials with the short peptide molecule 415 (phenylalanine-serine-lysine) at a mass ratio of 1:2, stir at room temperature for 5 minutes to obtain a uniformly dispersed solution, and then add 0.005 parts by mass of 1- Ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine were stirred at 100°C for 3 hours. The resulting solution was centrifuged at a speed of 8,000 rpm, and the sediment was washed with deionized water and redispersed to a suitable concentration to obtain a MXene nanosensing layer co-modified with titanium dioxide nanoparticles and short peptides, which was sprayed with a spray gun after plasma cleaning. The sensor substrate 411 and the gold interdigitated electrodes 412 are dried and finally the MXene acetone sensor 41 is obtained.

The functional modules of the detection system of the device are shown in Figure 8. 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 transistor, 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 provides reference voltage Vref for constant current source, obtains analog-to-digital converter sampling signal through bus such as I2C, performs data transmission with Bluetooth, and controls field effect tube on and off, wait. The constant current source outputs a constant test current Imeasure according to the reference voltage Vref. After passing through the MXene acetone sensor 41, a voltage signal is generated, filtered by a low-pass network to remove power frequency noise interference, and finally converted by an 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 to realize the switch of the light-emitting diode 442 to control the light irradiation time of the MXene acetone sensor 41 . Bluetooth performs signal transmission with the mobile terminal through wireless communication, and performs data processing and display on the mobile terminal. The system is powered by the battery and the power management module, which provides the power supply voltage Vcc to drive the detection circuit 423 . In order to achieve a compact and miniaturized circuit design, the detection circuit 423 can use micro-chips with low power consumption, including but not limited to MSP430FR2632 microprocessor chips, AD8605 operational amplifier chips, ADS1115 analog-to-digital conversion chips, and the like.

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

Since the MXene acetone sensor 41 has an irreversible acetone adsorption phenomenon, in order to realize acetone sensing and detection with good repeatability and quantitative analysis, the present invention introduces a light-emitting diode 442 to irradiate the MXene acetone 41 sensor with light. Since the photoelectric response heterogeneous interface composed of titanium dioxide nanoparticles 414 and MXene nano-sensing layer 413 in the MXene acetone sensor 41 can generate photogenerated carriers under light irradiation conditions, and improve the acetone desorption situation, so in acetone detection During this period, keep the LED 442 turned on to correct the response of the MXene acetone sensor 41 .

As shown in FIG. 9 , when acetone gas is fed, the MXene acetone sensor 41 produces a positive normalized resistance response, indicating that the sensor resistance increases with the acetone gas being fed. The acetone response returned to the baseline value after the air was reintroduced, indicating that the acetone response was completely reversible under light irradiation, and the response value increased sequentially with the increase of the acetone concentration. In addition, FIG. 9 shows that the MXene acetone sensor 41 has a faster acetone response and recovery speed, which is beneficial to further shorten the time for exhaled gas analysis. Three independent repeated experiments were performed on the same batch of MXene acetone sensor 41, and the obtained results were plotted as scatter plots and piecewise linear fitting was used. As shown in Figure 10, the acetone response presents a linear correlation in the concentration ranges of 0.5-2ppm and 2-50ppm respectively, wherein the linear correlation coefficient R in the range of ^0.5-2ppm is 0.98, and the sensitivity is 0.672%/ppm; ^The linear correlation coefficient R2 in the range is 0.97, and the sensitivity is 0.145%/ppm. The results of independent repeated tests have good agreement, as shown by the smaller error bars in Figure 10.

In this embodiment, the detection repeatability and long-term stability of the MXene acetone sensor 41 are tested. As shown in Figures 11-12, the MXene acetone sensor 41 exhibits good reversibility in the response-recovery of 5ppm acetone for multiple consecutive cycles, and the response amplitude remains well consistent. The stability test for 15 consecutive days shows that the MXene acetone sensor 41 has good long-term stability, and can be applied to long-term exhaled breath acetone detection with a small response attenuation.

Typical interfering substances such as humidity, exhaled ethanol, ammonia, etc. that exist in the exhaled air, as a preferred embodiment, the present invention proposes a fabric filter 5 based on MXene that can suppress respiratory interference, and the fabric filter 5 based on MXene is made of platinum The nanoparticle-loaded MXene fabric 52 is composed of an active desiccant 51, as shown in FIG. 6 . 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, and the like. Platinum nanoparticles loaded MXene fabric 52 was prepared by a two-step solution processing method, as shown in Fig. 7 . First, white cotton fabrics washed and dried in deionized water were soaked in 5 mg/mL MXene solution and deposited for 30 min. The stable electrostatic adsorption of MXene on cotton fabric was realized by utilizing the hydrogen bond network formed by MXene and abundant oxygen-containing functional groups on the surface of cotton fabric. The unadsorbed MXene was rinsed with deionized water and dried. Repeat the above steps until you get a black MXene fabric. The obtained MXene fabric was soaked in a 3.86 nM chloroplatinic acid solution and reacted for 30 minutes. The chemically active surface of MXene was used to realize the in situ reduction of platinum nanoparticles, and the platinum nanoparticle-loaded MXene fabric 52 was prepared. The active desiccant 51 is filled between the platinum nanoparticle-loaded MXene fabrics 52, and the platinum nanoparticle-loaded MXene fabric 52 is encapsulated and bonded with polydimethylsiloxane glue with good air permeability to obtain an MXene-based fabric filter 5.

The invention calibrates its interference filtering performance. As shown in Figures 13-16, the experimental simulated exhaled air (5% carbon dioxide, 79% nitrogen, 16% oxygen) was mixed with 10ppm ammonia, ethanol, acetone and 90% relative humidity to obtain unfiltered standard gas. Use the MXene acetone sensor 41 to test the unfiltered interference response, and use a commercial hygrometer to calibrate the humidity, and a gas chromatograph to calibrate the concentrations of ammonia, ethanol, and acetone. Simultaneously, the simulated exhaled air containing interfering substances is passed through the fabric filter 5 based on MXene, the filtered simulated exhaled air is tested for response by the MXene acetone sensor 41, and the tail gas is collected with an air bag to calibrate the humidity of the commercial hygrometer again, and the gas chromatograph calibrates the ammonia Gas, ethanol, acetone concentration. Figures 13-16 show 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 response to acetone. Therefore, the MXene-based fabric filter 5 can improve the selectivity of exhaled acetone detection.

Further, the device of the present invention can realize selective detection of acetone in exhaled breath in the presence of interfering substances. As shown in Figure 17, the experiment was configured with 90% RH humidity simulated exhaled air mixed with 10ppm acetone, ammonia, ethanol, hexane, and isoprene respectively. The test results showed that the device of the present invention produced the highest response to acetone. It has obvious suppression of polar and non-polar exhaled breath interferers, and can meet the requirements of acetone detection in the complex environment of exhaled breath from the perspective of selectivity.

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 to form an MXene smart mask 11, wherein the exhaled acetone detection label 4 is fixed on the disposable mask 1 between the outer respiration valve 2 and the respiration valve housing 3 for detecting the concentration of acetone in the exhaled air. The fabric filter 5 based on MXene is fixed on the breathing valve 2 inside the disposable mask 1, and is used to filter the exhaled air passing through the breathing valve 2, as shown in Figure 1-2.

Fig. 18 is a schematic diagram of an implementation of the MXene smart mask 11 provided by the embodiment of the present invention. The MXene-based fabric filter 5 is assembled on the inner surface of the disposable mask 1 close to the breathing valve 2, and the exhaled acetone detection label 4 is assembled between the breathing valve 2 on the outer side of the disposable mask 1 and the breathing valve shell 3. Wireless transmission realizes data communication and subsequent data display processing between the MXene smart mask 11 and the mobile terminal 12 for exhaled acetone detection. The exhaled air is filtered through the MXene-based fabric filter 5, passes through the detection circuit board opening 421 and the packaging layer opening 431, and is directly detected by the MXene acetone sensor 41 without other pretreatment. The mobile terminal 12 draws a continuous real-time respiratory curve according to the received data, and displays the exhaled breath rhythm and the change of exhaled acetone concentration caused by breathing activity in the real-time respiratory curve display functional area 13, and the respiratory result analysis functional area 14 displays the calculated exhaled breath. Gas acetone concentration and breath rate per minute.

Further, in this embodiment, 5 volunteers were recruited to carry out in-body breathing test verification on the MXene smart mask 11 described in the present invention, and the blood ketone concentration changes of the 5 volunteers were detected as a standard reference for the change of acetone concentration in exhaled breath. Blood ketone test is a commonly used clinical method for ketone body testing, and it is also a common reference value for exhaled acetone testing. During the experiment, the volunteers followed the guidance of the experimenters, wore the MXene smart mask 11 for exhaled acetone detection, and performed the exhaled acetone test within 5 minutes, and at the same time collected fingertip blood and tested the blood ketone level. Alcohol swabs were used to sterilize fingertips before blood collection, blood collection pens and disposable minimally invasive blood collection needles were used during blood collection, and blood ketone levels were detected with standard biochemical test strips as a reference. A breath acetone test and a blood ketone level test count as one standard test. Among them, two volunteers participated in the diet experiment, and they ate a balanced diet, a ketogenic diet, and a high-carbohydrate diet within three days. They performed a standard test at 5:30 and 8:30 on the first day, and the second day from the morning A standard test was performed every 3 hours from 8:30 to 8:30 pm, and a standard test was performed every 3 hours from 8:30 am to 5:30 pm on the third day, with a total of 11 standard tests per person. The other three volunteers participated in the exercise test. They had two half-hour cycling exercises on weekdays, totaling an hour of exercise. The experiment controlled the exercise load of the subjects, and monitored the cardiac output as a reference for exercise intensity. Then the volunteers needed to There was a total of two hours of sitting and rest, and the experiment lasted a total of three hours. During the test period, standard tests were performed at 0, 30, 90, 120, and 180 minutes, and each person had a total of 5 standard tests.

As shown in Figure 19, the MXene smart mask 11 provided by the embodiment of the present invention is used to detect acetone in exhaled breath, and the correlation analysis between the obtained results and the blood ketone level of volunteers is carried out. The Pearson correlation coefficient between exhaled 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 acetone detection.

It should be noted that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. On the premise of no creative work, any modification, equivalent replacement, improvement, etc. should be included in the protection scope of the present invention.

Claims (10)

1. The utility model provides a wearable exhaled breath acetone detection device based on MXene which characterized in that, it includes: an exhaled breath acetone detection label (4); the exhaled breath acetone detection label (4) comprises an MXene acetone sensor (41), a flexible detection circuit board (42), a polydimethylsiloxane packaging layer (43) for packaging the flexible detection circuit board (42) and a light-emitting diode circuit board (44) which are sequentially assembled 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 on the light-emitting diode substrate (441), and windows are arranged on the flexible detection circuit board (42) and the polydimethylsiloxane packaging layer (43) so that the light-emitting diode (442) is opposite to the MXene acetone sensor (41); the diode circuit board (44) and the MXene acetone sensor (41) are electrically connected with the flexible detection circuit board (42); the MXene acetone sensor (41) is used for detecting the concentration of acetone in the exhaled breath and converting the acetone into an electric signal, and the flexible detection circuit board (42) is used for acquiring and processing the electric signal of the MXene acetone sensor (41); the MXene acetone sensor (41) comprises a sensor substrate (411), a gold interdigital electrode (412) and an MXene nano sensing layer (413) which are sequentially assembled from bottom to top, wherein titanium dioxide nanoparticles (414) and short peptide molecules (415) are modified on the surface of the MXene nano sensing layer (413).

2. The device according to claim 1, wherein the MXene nano sensing layer (413) is prepared by mixing 2 parts by mass of ceramic phase titanium aluminum carbon powder, 2 parts by mass of lithium fluoride and 40 parts by volume of concentrated hydrochloric acid, etching at 40 ℃ for 24 hours, cleaning precipitate by deionized water, and spraying the mixture on the surface of the gold interdigital electrode (412) after ultrasonic mechanical stripping assisted by a vortex generator.

3. The device according to claim 1, characterized in that the titanium dioxide nanoparticles (414) are modified by: mixing the MXene nano sensing layer (413) with 3% of hydrogen peroxide solution by mass fraction, and heating in a water bath at 80 ℃ to obtain the nano sensing material, wherein the titanium dioxide nano particles (414) grow on the MXene nano sensing layer (413) in situ.

4. The device of claim 1, wherein the short peptide molecule (415) is modified by: mixing and dissolving the MXene nano sensing layer (413) of the in-situ grown titanium dioxide nanoparticles (414) according to the mass ratio of 1.

5. The device according to claim 1, further comprising an MXene-based fabric filter (5) for filtering exhaled breath; the MXene-based fabric filter (5) is composed of a platinum nanoparticle-loaded MXene fabric (52) and an active drying agent (51) wrapped in the platinum nanoparticle-loaded MXene fabric (52), wherein the platinum nanoparticle-loaded MXene fabric (52) is obtained by performing electrostatic adsorption on MXene on the surface of cotton fabric and performing in-situ reduction on the loaded platinum nanoparticles on the MXene surface in a chloroplatinic acid solution.

6. The device according to claim 5, characterized in that the platinum nanoparticle loaded MXene fabric (52) is prepared in particular by: the white cotton fabric which is washed by deionized water and dried is soaked in 5mg/mL MXene solution, deposition is carried out for 30 minutes, the white cotton fabric is repeatedly washed and dried and then soaked in 3.86mM chloroplatinic acid solution, reaction is carried out for 30 minutes, and the in-situ reduction of the platinum nanoparticles is realized by utilizing the chemical active surface of MXene.

7. The device according to claim 1, wherein 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 comprises a miniature low-power chip and a peripheral resistor-capacitor, and is used for acquiring and processing the electric signal of the MXene acetone sensor (41); and respectively welding the light-emitting diode circuit board (44) and the MXene acetone sensor (41) on the diode circuit connecting pad (424) and the sensor connecting pad (425) through low-temperature soldering tin, so that the electrical connection between the diode circuit board (44), the MXene acetone sensor (41) and the flexible detection circuit board (42) is realized.

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 power management circuit, and a peripheral resistor-capacitor.

9. The device according to any one of claims 1 to 8, further comprising a disposable mask (1), a breather valve (2) and a breather valve housing (3) fixed on the disposable mask (1), wherein the exhaled breath acetone detection label (4) is fixed between the breather valve (2) and the breather valve housing (3) on the outside of the disposable mask (1), and an MXene-based fabric filter (5) is fixed on the breather valve (2) on the inside of the disposable mask (1) for filtering the exhaled breath passing through the breather valve (2).

10. A detection method of exhaled breath acetone based on MXene is characterized by comprising the following steps:

use of the device of any of claims 1-9 to obtain the acetone concentration of exhaled breath, keeping the light emitting diode (442) on during the acetone detection.

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