Breath Acetone Research Articles

Ultrasensitive Acetone Gas Sensor Based on a K/Sn-Co3O4 Porous Microsphere for Noninvasive Diabetes Diagnosis.

The detection of acetone in human exhaled breath is crucial for the noninvasive diagnosis of diabetes. However, the direct and reliable detection of acetone in exhaled breath with high humidity at the parts per billion level remains a great challenge. Here, an ultrasensitive acetone gas sensor based on a K/Sn-Co3O4 porous microsphere was reported. The sensor demonstrates a detection limit of up to 100 ppb, along with excellent repeatability and selectivity. Remarkably, without the removal of water vapor from exhaled breath, the sensor can accurately distinguish diabetic patients and healthy individuals according to the difference in acetone concentrations, demonstrating its great potential for diabetes diagnosis. The enhanced sensitivity of the sensor is attributed to the increased oxygen adsorption on the material surface due to K/Sn codoping and the stronger coadsorption of Sn-K atoms to acetone molecules. These findings shed light on the mechanisms underlying the sensor's improved performance.

Photoacoustic Trace-Analysis of Breath Isoprene and Acetone via Interband- and Quantum Cascade Lasers

This research presents two laser-based photoacoustic approaches for analyzing exhaled breath isoprene and acetone. The integration of a PTR-ToF-MS as a reference device ensured the reliability and accuracy of the photoacoustic systems that is based on an ICL for isoprene and a QCL for acetone detection. The calibration yielded limits of detection of 26.9 ppbV and 1.7 ppbV, respectively, and corresponding normalized noise equivalent absorption coefficients (NNEAs) of 5.0E-9 Wcm-1Hz-0.5 and 4.9E-9 Wcm-1Hz-0.5. Laboratory as well as real breath sample measurements from alveolar breath revealed a robust system performance, with only one outlier within the static isoprene measurements. However, discrepancies emerged under dynamic breath sampling conditions, emphasizing the need for further optimization. Especially by knowing the dynamic nature and endogenous origin of exhaled isoprene our findings highlight the potential of breath analysis for non-invasive physio-metabolic and pathophysiological monitoring towards point-of-care devices.

Porous PDMS-ZnO Wearable Gas Sensor for Acetone Biomarker Detection and Breath Analysis.

In response to the growing demand for global health monitoring, we report a nonintrusive health detection method using a compact, conformal wearable ultraviolet (UV)-assisted gas-sensing system based on an intrinsically flexible porous polydimethylsiloxane (PDMS)-zinc oxide (ZnO) composite layer (PPZL) for the breath acetone (BrAce) detection and breath event analysis. The enhanced acetone response is attributed to the synergistic effect of UV irradiation and the high surface area of the porous structure, which also improves the mechanical robustness. The UV-assisted wearable sensor reliably detects acetone concentrations ranging from 1 to 100 ppm at room temperature under 4.05 mW/cm2 UV intensity, even under mechanical strains such as a bending radius of 5 mm and 60% tensile strain. It accurately analyzes different breathing patterns (12-20 breaths per minute) and BrAce concentrations, maintaining a stable performance over 20 days with less than 5% signal degradation. The sensor exhibits response and recovery times of average 110-150 and 130-180 s, respectively, and maintains a consistent 3 ppm BrAce response under varying humidity levels up to 70% relative humidity, ensuring accurate detection of BrAce concentrations during real-world breath tests. Additionally, the sensor targets only specific gases, and the sensor's selectivity is not a key concern. This flexible acetone gas sensor offers a portable solution for health management and a fabrication method for designing flexible metal oxide materials.

Temperature-modulated acetone monitoring using Al2O3-coated evanescent wave fiber optic sensors

This paper presents an experimental study of a fiber-optic-based acetone sensor and its temperature effects for use as a breath analyzer to detect acetone in exhaled breath. The study employs fiber optic evanescent wave-based acetone sensing, utilizing sputter coated Aluminium Oxide (Al2O3)-coated probes fabricated via clad modification technique. The optical fibers were coated with Al2O3 to achieve thicknesses of 247.03 nm, 334.05 nm, and 468.75 nm. The sensor probes were characterized using, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Ultraviolet-Visible (UV-Vis) Spectroscopy, and Spectroscopic Ellipsometry for uniformity, elemental, optical constants, and thickness of the Al2O3. The spectral responses of the probes were analyzed for acetone concentrations ranging from 0 to 100 ppm, with temperature modulation from room temperature to 100 °C. The probe with a ∼334 nm thick Al2O3 coating exhibited the highest response, reaching 6.2 % at 100 °C in 100 ppm acetone. Linear regression revealed that the ∼334 nm coated probe had the highest sensitivity at 5.98 counts/ppm. The sensor showed response and recovery times of approximately 12 and 17 seconds, respectively. This study underscores the stability and repeatability of temperature-modulated Al2O3-coated fiber optic sensors for selective acetone detection in various non-invasive applications.

Effects of a Carbohydrate Meal on Lipolysis

Background: Due to the increasing prevalence of obesity and type 2 diabetes, effective dietary recommendations are needed. Previously, we developed the low-insulin method: by avoiding insulinogenic, i.e., insulin-release-triggering foods, insulin secretion becomes reduced, lipolysis is stimulated, and energy production is shifted to ketosis with excess ketone bodies exhaled in the form of acetone. Now, we investigate how quickly stable ketosis (defined as fasting breath acetone concentration ≥ 7.0 ppm) is achieved, whether and for how long a carbohydrate meal inhibits ketosis, and whether the responses differ in healthy adults with different insulin levels. Methods: An oral glucose tolerance test was conducted, and body composition and fasting insulin were determined at the beginning and end of the 14-day study. Participants (n = 10) followed a ketogenic diet and performed continuous glucose monitoring. Ketosis levels were determined by measuring breath acetone concentrations. On day 8, two white bread rolls with jam (72 g carbohydrates) were consumed for breakfast. Results: After seven days, all participants achieved stable ketosis (defined as fasting breath acetone concentration ≥ 7.0 ppm), which dropped from 8.2 to 5.7 ppm (p = 0.0014) after the carbohydrate meal. It took five days to achieve stable ketosis again. The stratification of participants into tertiles according to their fasting insulin levels demonstrated that individuals with low fasting insulin levels achieved stable ketosis again after two days and those with medium insulin levels after five days, while those with high baseline values did not reach stable ketosis by the end of the study. Conclusions: By carbohydrate restriction, stable ketosis can be achieved within one week. However, a single carbohydrate meal inhibits ketosis for several days. This effect is pronounced in individuals with elevated fasting insulin levels.

Deep-Learning-Based Blood Glucose Detection Device Using Acetone Exhaled Breath Sensing Features of α-Fe2O3-MWCNT Nanocomposites.

Owing to the correlation between acetone in human's exhaled breath (EB) and blood glucose, the development of EB acetone gas-sensing devices is important for early diagnosis of diabetes diseases. In this article, a noninvasive blood glucose detection device through acetone sensing in EB, based on an α-Fe2O3-multiwalled carbon nanotube (MWCNT) nanocomposite, was successfully developed. Different amounts of α-Fe2O3 were added to the MWCNTs by a simple solution method. The optimized acetone gas sensor showed a response of 5.15 to 10 ppm acetone gas at 200 °C. Also, the fabricated sensor showed very good sensing properties even in an atmosphere with high relative humidity. Since the EB has high humidity, the proposed sensor is a promising device to exactly detect the amount of acetone in EB with high humidity. The sensor was powered by a 3200 mAh battery with the possibility of charging using mains electricity. To increase the reliability and calibration of the sensing device, a practical test was taken to detect acetone EB from 50 volunteers, and a deep learning algorithm (DLA) was used to detect the effect of various factors on the amount of acetone in each person's acetone EB. The proposed device with ±15 errors had almost 85% correct responses. Also, the proposed device had excellent response, short response time, good selectivity, and good repeatability, leading it to be a suitable candidate for noninvasive blood glucose sensing.

The detection of acetone in exhaled breath using gas Pre-Concentrator by modified Metal-Organic framework nanoparticles

Volatile organic compounds (VOCs) from exhaled breath are promising indicators for the diagnostics of human health conditions. However, the composition of breath is rather complex, including water vapors and various tiny amounts of gases and biomarkers. Pre-concentrator plays a significant role in capturing and concentrating target gas in the gas mixture. In this work, the MIL-101 (Cr) nanoparticles are coated with polydimethylsiloxane (PDMS) through physical vapor deposition process to concentrate acetone under high humidity and room temperature. Experimentally, the newly developed material exhibits significant improvement in signal intensity that is 76.3 times greater than a commercial reference material under relative humility of 80 %. The detection range is also proven to be desirable (from 100 ppb to 2500 ppb), capturing the spectrum of acetone concentrations typically found in human exhaled breath. Moreover, following a thermal desorption process, the device demonstrates a high degree of linearity with a coefficient of 0.9956. The modified metal–organic framework materials are made into a flexible thin-film-shape device, that could be embedded in a facemask. The proposed device could meet the critical requirements for sampling, concentrating and detecting of exhaled breath biomarkers, thereby opening a new opportunity as part of the flexible electronic systems on face masks to facilitate quantitative breath analyses.

Development of polyimide nanofiber aerogels with a 3D multi-level pore structure: A new sensor for colorimetric detection of breath acetone

Polyimide nanofiber aerogels loaded with thymol blue and hydroxylamine sulfate (TB-HAS@PI NFAs) were synthesized and employed as a novel sensor for colorimetric detection of breath acetone (BrAce). The enhancement of 3D multi-level pore structure of TB-HAS@PI NFAs for sensing performance was elucidated through systematical characterization results. Because the designed sensing system relied on the specific reaction of HAS with acetone, TB-HAS@PI NFAs exhibited a more sensitive response ability to acetone, ensuring that the colorimetric sensing detection will not be interfered by other coexisting gas in exhaled breath. Moreover, the sensor demonstrated a rapid response, with color changes quantitatively measured within 30 s of exposure to acetone gas. Importantly, the feasibility and accuracy of established method were confirmed through comparison with GC–MS. This research provided a promising strategy for daily health management of healthy people and diabetics.

Femtosecond Laser Ionization Mass Spectrometry for Online Analysis of Human Exhaled Breath.

A variety of organic compounds in human exhaled breath were measured online by mass spectrometry using the fifth (206 nm) and fourth (257 nm) harmonic emissions of a femtosecond ytterbium (Yb) laser as the ionization source. Molecular ions were enhanced significantly by means of resonance-enhanced, two-color, two-photon ionization, which was useful for discrimination of analytes against the background. The limit of detection was 0.15 ppm for acetone in air. The concentration of acetone in exhaled breath was determined for three subjects to average 0.31 ppm, which lies within the range of normal healthy subjects and is appreciably lower than the range for patients with diabetes mellitus. Many other constituents, which could be assigned to acetaldehyde, ethanol, isoprene, phenol, octane, ethyl butanoate, indole, octanol, etc., were observed in the exhaled air. Therefore, the present approach shows potential for use in the online analysis of diabetes mellitus and also for the diagnosis of various diseases, such as COVID-19 and cancers.

A solid state electrolyte based enzymatic acetone sensor

This paper introduces a novel solid-state electrolyte-based enzymatic sensor designed for the detection of acetone, along with an examination of its performance under various surface modifications aimed at optimizing its sensing capabilities. To measure acetone concentrations in both liquid and vapor states, cyclic voltammetry and amperometry techniques were employed, utilizing disposable screen-printed electrodes consisting of a platinum working electrode, a platinum counter electrode, and a silver reference electrode. Four different surface modifications, involving different combinations of Nafion (N) and enzyme (E) layers (N + E; N + E + N; N + N + E; N + N + E + N), were tested to identify the most effective configuration for a sensor that can be used for breath acetone detection. The sensor's essential characteristics, including linearity, sensitivity, reproducibility, and limit of detection, were thoroughly evaluated through a range of experiments spanning concentrations from 1 µM to 25 mM. Changes in acetone concentration were monitored by comparing currents readings at different acetone concentrations. The sensor exhibited high sensitivity, and a linear response to acetone concentration in both liquid and gas phases within the specified concentration range, with correlation coefficients ranging from 0.92 to 0.98. Furthermore, the sensor achieved a rapid response time of 30–50 s and an impressive detection limit as low as 0.03 µM. The results indicated that the sensor exhibited the best linearity, sensitivity, and limit of detection when four layers were employed (N + N + E + N).

Enhancing Precision Nutrition: Investigating the Interplay of Breath Acetone and Body Composition in Division I Athletes

Enhancing Precision Nutrition: Investigating the Interplay of Breath Acetone and Body Composition in Division I Athletes

78-OR: Breath Acetone Correlates with Capillary Beta Hydroxybutyrate in Type 1 Diabetes

78-OR: Breath Acetone Correlates with Capillary Beta Hydroxybutyrate in Type 1 Diabetes

Innovations and applications of ketone body monitoring in diabetes care.

Ketone bodies, comprising β-hydroxybutyric acid (BHB), acetoacetate (AcAc), and acetone, play a vital role as essential energy substrates. In individuals with diabetes, ketone bodies can be elevated under various conditions, including diabetic ketoacidosis, use of sodium-glucose transporter type 2 (SGLT2) inhibitors, and extreme carbohydrate restriction. There are three methods for measuring ketone bodies. Urine ketone analysis (AcAc) is a standard clinical test, whereas blood ketone testing (BHB+AcAc) is valuable in identifying or resolving diabetic ketoacidosis. Recently, technology for measuring breath acetone has been introduced, which provides an easy means of monitoring ketogenic diets in obese individuals. The basic breath alcohol detector also reacts with breath acetone. Therefore, it is important for professional drivers taking SGLT2 inhibitors to be cautious as workplace breath alcohol detectors may show false-positive results. Conversely, if a positive result is obtained, a detailed examination of ketosis is necessary. This review provides an overview of ketone body measurements in individuals with diabetes.

#2160 Ketosis moderates the effect on kidney volume in dietary interventions for ADPKD—more insights on the KETO ADPKD trial

Abstract Background and Aims Autosomal-dominant polycystic kidney disease (ADPKD) is the most common monogenic disease leading to kidney failure. Tolvaptan, the only approved targeted treatment strategy, comes with adverse events such as hepatotoxicity and massive polyuria, limiting its use. Novel treatment strategies are urgently needed. Cyst-lining epithelial cells are glucose-dependent and metabolically inflexible. Evidence from polycystic kidney disease (PKD) animal models show that ketogenic dietary interventions (KDI) can ameliorate cyst growth and loss of kidney function. To enable clinical translation of these findings, our group set up a series of trials—from small cohorts and proof of principle studies to our most recent trial KETO-ADPKD, showing that KDIs are feasible and can work as a treatment for ADPKD [1]. This has received a lot of attention. With this post-hoc analyses, we aim to share further in-depth analyses of the factors moderating the effects we see on ADPKD. Method KETO-ADPKD is an exploratory randomized and controlled clinical trial (NCT04680780). Sixty-six patients were randomized to 3 months dietary intervention (ketogenic diet [KD] or water fasting [WF]) or the control group. Here, we explore correlations between biochemical readout parameters of ketosis and markers of disease progression. Results The KD group shows a promising, yet statistically not significant decline in height-adjusted total kidney volume (htTKV). Patients reaching high biochemical thresholds of ketosis however significantly reduced their htTKV in comparison with the control group (KD −16.3 ml/m, CG + 14.8 ml/m, p-value 0.049). This becomes even clearer when higher thresholds for adherence are administered: In a smaller group requiring not only beta-hydroxybutyrate (BHB) levels ≥0.5 mmol/l but breath acetone ≥5 ppm on 75% of daily measurements, htTKV could be reduced by −17.6 ml/m (KD) vs +14.8 ml/m (CG), p-value 0.026. The significant reduction of liver volume upon KD is not influenced by the level of ketosis. Beneficial effects on estimated glomerular filtration rate (eGFR) can be equally observed in all subsets. Weight loss ≥5% was nor associated with a more significant loss of kidney nor liver volume. Conclusion Subgroup analyses of the KETO-ADPKD trial show stronger impact of the dietary intervention with higher ketone body levels. In particular, ketogenesis as a marker of metabolic reprogramming strongly moderates the effects we see on kidney volume. The assessment of renal cyst fractions could further enlighten the effects on cyst burden. This is in line with preclinical data showing that ketosis rather than caloric intake is responsible for the amelioration of disease progression [2].

Yolk-shell microspheres perovskite Gd/Fe oxides with rich oxygen vacancies for ultra-sensitive properties in acetone detection

Acetone as a toxic and hazardous gas is widely appeared in life. In this paper, p-type Gd/Fe oxide yolk-shell microspheres were prepared by a one-step hydrothermal method. Characterization and test results shows that perovskite Gd/Fe oxides with yolk-shell microspheres possess abundant oxygen vacancies, which presents excellent acetone gas-sensitive performance. Among the obtained sensor, the optimal operating temperature of the S-4 (Gd0.77/Fe) sensor is reduced to 200 ℃, and the response value (S = 20) to 100 ppm acetone is improved by 5 times (compare to S-1). The lowest detection limit can be as low as 0.5 ppm, furthermore the sensor presents resist-humidity. Electron paramagnetic resonance (EPR) and x-ray photoelectron spectroscopy (XPS) results reveal that the ratio of Gd/Fe has a strong correlation with the content of oxygen vacancies. The rich oxygen vacancies control theory is the main reason for improving gas sensing performance in this work. The presence of oxygen vacancies effectively increases the active sites and further promotes intermolecular interactions. Overall, the sensor S-4 (Gd0.77/Fe) has an important potential in the detection of acetone in human breath with high response and low detection limit under high humidity environment.

Structure-dependent biomorphology Co3O4-In2O3 nanorods for expired acetone gas sensor

Currently, the detection of acetone in exhaled breath is extensively utilized for the preliminary diagnosis of diabetes and for tracking fat oxidation in exercise. However, semiconductor gas sensors often require enhancement in breath analysis because of their inherent limitations in selectivity and sensitivity to humidity. In this research, we have synthesized an effective and humidity-unaffected acetone sensing material. This was achieved by utilizing the surface induction effect of porous biomass carbon derived from hemp stems to promote the dispersion of Co3O4-In2O3 heterostructure composites, thereby increasing the availability of active sites. This unique structure is achieved by precisely integrating the p-n heterostructure formed by Co3O4-In2O3 nanorods with the hierarchical porous carbon skeleton obtained via the calcination of templates. The p-n heterostructure enhances charge carrier concentration at the interface, thereby augmenting the activation of surface-active oxygen. The composite material's interface barrier improves sensor selectivity, reducing operating temperature (200 °C) and enhancing response rate. In this work, our best sample Coln-3/BC gas sensor exhibits excellent response towards acetone gas (S=Rair/Rgas=56.8 at 100 ppm), low detection limit of 10 ppb, a linear relationship between sensing response and humidity that strikes a balance between irrelevance as well as exceptional selectivity and stability. Therefore, constructing hierarchical structures and gas-sensing materials based on p-n heterojunctions holds promising prospects.

An inexpensive UV-LED photoacoustic based real-time sensor-system detecting exhaled trace-acetone

In this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) – providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 8.3 ppbV and an NNEA of 1.4E-9 Wcm−1Hz−0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field.

Nanowire Array Breath Acetone Sensor for Diabetes Monitoring.

Diabetic ketoacidosis (DKA) is a life-threatening acute complication of diabetes characterized by the accumulation of ketone bodies in the blood. Breath acetone, a ketone, directly correlates with blood ketones. Therefore, monitoring breath acetone can significantly enhance the safety and efficacy of diabetes care. In this work, the design and fabrication of an InP/Pt/chitosan nanowire array-based chemiresistive acetone sensor is reported. By incorporation of chitosan as a surface-functional layer and a Pt Schottky contact for efficient charge transfer processes and photovoltaic effect, self-powered, highly selective acetone sensing is achieved. The sensor has exhibited an ultra-wide acetone detection range from sub-ppb to >100 000ppm level at room temperature, covering those in the exhaled breath from healthy individuals (300-800ppb) to people at high risk of DKA (>75ppm). The nanowire sensor has also been successfully integrated into a handheld breath testing prototype, the Ketowhistle, which can successfully detect different ranges of acetone concentrations insimulated breath samples. The Ketowhistle demonstrates the immediate potential for non-invasive ketone monitoring for people living with diabetes, in particular for DKA prevention.

Quantifying exhaled acetone and isoprene through solid phase microextraction and gas chromatography-mass spectrometry

BackgroundAcetone, isoprene, and other volatile organic compounds (VOCs) in exhaled breath have been shown to be biomarkers for many medical conditions. Researchers use different techniques for VOC detection, including solid phase microextraction (SPME), to preconcentrate volatile analytes prior to instrumental analysis by gas chromatography-mass spectrometry (GC-MS). These techniques include a previously developed method to detect VOCs in breath directly using SPME, but it is uncommon for studies to quantify exhaled volatiles because it can be time consuming due to the need of many external/internal standards, and there is no standardized or widely accepted method. The objective of this study was to develop an accessible method to quantify acetone and isoprene in breath by SPME GC-MS. ResultsA system was developed to mimic human exhalation and expose VOCs to a SPME fiber in the gas phase at known concentrations. VOCs were bubbled/diluted with dry air at a fixed flow rate, duration, and volume that was comparable to a previously developed breath sampling method. Identification of acetone and isoprene through GC-MS was verified using standards and observing overlaps in chromatographic retention/mass spectral fragmentation. Calibration curves were developed for these two analytes, which showed a high degree of linear correlation. Acetone and isoprene displayed limits of detection/quantification equal to 12 ppb/37 ppb and 73 ppb/222 ppb respectively. Quantification results in healthy breath samples (n = 15) showed acetone concentrations spanned between 71 ppb and 294 ppb, and isoprene varied between 170 ppb and 990 ppb. Both concentration ranges for acetone and isoprene in this study overlap with those reported in existing literature. SignificanceResults indicate the development of a system to quantify acetone and isoprene in breath that can be adapted to diverse sampling methods and instrumental analyses beyond SPME GC-MS.

Effectiveness of breath acetone monitoring in reducing body fat and improving body composition: a randomized controlled study

When attempts to lose body fat mass frequently fail, breath acetone (BA) monitoring may assist fat mass loss during a low-carbohydrate diet as it can provide real-time body fat oxidation levels. This randomized controlled study aimed to evaluate the effectiveness of monitoring BA levels and providing feedback on fat oxidation during a three-week low-carbohydrate diet intervention. Forty-seven participants (mean age = 27.8 ± 4.4 years, 53.3% females, body mass index = 24.1 ± 3.4 kg m−2) were randomly assigned to three groups (1:1:1 ratio): daily BA assessment with a low-carbohydrate diet, body weight assessment (body scale (BS)) with a low-carbohydrate diet, and low-carbohydrate diet only. Primary outcome was the change in fat mass and secondary outcomes were the changes in body weight and body composition. Forty-five participants completed the study (compliance rate: 95.7%). Fat mass was significantly reduced in all three groups (all P < 0.05); however, the greatest reduction in fat mass was observed in the BA group compared to the BS (differences in changes in fat mass, −1.1 kg; 95% confidence interval: −2.3, −0.2; P = 0.040) and control (differences in changes in fat mass, −1.3 kg; 95% confidence interval: −2.1, −0.4; P = 0.013) groups. The BA group showed significantly greater reductions in body weight and visceral fat mass than the BS and control groups (all P < 0.05). In addition, the percent body fat and skeletal muscle mass were significantly reduced in both BA and BS groups (all P < 0.05). However, no significant differences were found in changes in body fat percentage and skeletal muscle mass between the study groups. Monitoring BA levels, which could have motivated participants to adhere more closely to the low-carbohydrate diet, to assess body fat oxidation rates may be an effective intervention for reducing body fat mass (compared to body weight assessment or control conditions). This approach could be beneficial for individuals seeking to manage body fat and prevent obesity.