Human breath monitoring is a quick and non-invasive method for identifying volatile organic compounds (VOCs) such as acetone, which may be markers of different diseases. A new article published in the journal Materials Science in Semiconductor Processing presents a comprehensive analysis of recent advancements in semiconductor metal oxide (SMO) gas detectors for identifying expelled acetone, which could help to replace invasive blood sugar monitoring.
Study: Detection of breath acetone by semiconductor metal oxide nanostructures-based gas sensors: A review. Image Credit: V/Shutterstock.com
Breath Evaluation for Diagnosis of Diabetes Mellitus
Diabetes mellitus (DM), a disease characterized by uncontrolled blood glucose levels, may induce organ death in individuals. Blood screenings are now being used in scientific research to examine and monitor blood glucose and ketone concentrations.
A blood specimen from a poked fingertip is deposited on a reactive strip in this approach, which is subsequently pre-inserted into an electromagnetic instrument to be evaluated. However, this treatment is uncomfortable, intrusive, and may be dangerous if not used correctly.
A breath assessment is an innovative and evolving procedure that capitalizes on contemporary measuring technology advancements. It is a non-invasive method of evaluating expelled breath elements to help diagnose disease, therapeutic assessment, and metabolic tracking.
Why is Measuring Acetone in Breath Important?
As a diabetic patient's body produces energy from fat rather than glucose, extra ketones, particularly acetone, are created. During breathing, the acetone is expelled. Acetone concentrations in the breath range from 0.3 to 0.9 parts per million in healthy persons to more than 1.8 parts per million in people with diabetes; therefore, acetone may function as an indicator in the blood for pathological conditions (diabetes). Furthermore, it has been established that there is a link between blood glucose levels and VOC concentrations such as acetone. As a result, measuring breath acetone may give greater diagnostic oversight over a diabetic person's state than measuring sugar levels alone.
Traditional exhalation assessment strategies are solely focused on spectrometric methodologies; however, with the improvement of gas sensors, they have become less attractive from a medical standpoint.
Sensing Materials for Breath Acetone Detection
Nanomaterials such as nanoparticles, nanosheets, and thin films have been employed to detect VOCs. However, all of these testing devices are expensive, and they are not accessible enough for daily blood sugar testing.
Chemo-resistive detectors have mostly been used in the past few decades to identify acetone (sub-ppm) in exhaled air. Different metal oxides, including zinc oxide, indium oxide, tin oxide, tungsten oxide, and titanium oxide, have been studied for acetone identification in real-time diabetes mellitus detection.
Graphene and its compounds, like graphene oxide (GO) and reduced graphene oxide (rGO), have also shown superior sensing capabilities toward acetone fumes for the monitoring of DM in real-time.
Identifying low levels of VOCs amid conflicting real-world conditions is the fundamental technical difficulty for detectors used for breath assessment. Many variables, including composite substances, structure, loading, temperature, moisture, and acetone content, have been discovered to offer significant challenges to the stable assessment of real-world breath specimens.
Applicability of Acetone Breath Sensors
Before beginning clinical treatment, the usage of acetone breath detectors should be evaluated. To be approved, the determined biomarkers must fulfill several criteria. Many metal oxide-based gas detectors can identify acetone levels ranging from 0.1 to 20 parts per million (ppm).
Although most of these perform well at elevated temperatures, the titanium oxide-based detector is the only one that can fulfill the criteria for breath acetone measurement for people with diabetes at reduced temperatures. It possesses fast reaction times and great responsiveness to low acetone levels.
It has been demonstrated that the loading of various metal oxides and the usage of various metallic nanoparticles have a greater influence on sensor performance than other factors, owing to the higher surface area. A wide surface area may offer a broad area of contact for the interaction between the sensing components and the targeted gases.
Several undiscovered characteristics in the literature on sensing performance, such as peak and lowest sensitivity, averaging, and long-term durability, must be examined before these sensors can be applied for detection in real-world environments.
The successful development of a simple acetone detector that ultimately fits in a case the size of a mobile phone could lower medical costs for the effective tracking and diagnosis of diabetes mellitus utilizing non-invasive techniques, particularly for those who have to inspect their blood sugar levels several times a day.
Ahmadipour, M. et al. (2022). Detection of breath acetone by semiconductor metal oxide nanostructures-based gas sensors: A review. Materials Science in Semiconductor Processing. Available at: https://doi.org/10.1016/j.mssp.2022.106897