Advanced vapour sensing materials: Existing and latent to acoustic wave sensors for VOCs detection as the potential exhaled breath biomarkers for lung cancer

Abstract

Lung cancer is the leading cause of death worldwide and has a significant impact on public health across society. Among all types of cancer, lung cancer is typically silent and it is commonly diagnosed at a later stage where treatment is rarely achievable. There is an urgent need for the development of the early diagnosis of lung cancer for an improved survival rate. Preliminary research shows that lung cancer is accompanied by increased oxidative stress which generates volatile organic compounds (VOCs). Hence, breath analysis offers the most promising solution for the early diagnosis of lung cancer as it is noninvasive and radiation free. Potential VOCs biomarkers in exhaled breath associated with oxidative stress and lipid peroxidation have been discussed to provide a quick approach to the diagnosis of lung cancer. Although gas chromatography-mass spectroscopy (GC-MS) able to analyze the VOCs biomarker, it is bulky, high cost, required expertise to handle and consumes a lot of time. Hence, the sensor-based technique provides the solution to overcome the limitation. Recently, acoustic wave sensors such as quartz crystal microbalance (QCM) and surface acoustic wave sensors (SAW) have been used to identify the presence of VOCs in various applications. This is due to its high selectivity, good reproducibility, and fast response sensing materials. The selection of vapour sensing materials plays a crucial role in developing a highly sensitive and selective and fast response acoustic wave sensors. For this purpose, various types of sensing layers from metal oxides, polymers, biopolymers and composites have been studied. We present a critical review of advanced vapour sensing materials that are primarily used in acoustic wave sensors in identifying the presence of various VOCs. Criteria to evaluate the performance of the acoustic wave sensors such as resonance frequency and sensitivity are also discussed.

Breath Analysis: A Promising Tool for Disease Diagnosis—The Role of Sensors

“…Similar to QCM sensors, MOS including ZnO, SiO 2 , TiO 2 , Co 3 O 4 , WO 3 , and other combinations [ 7 , 172 ], have been used extensively for SAW devices and most commonly for selective VOCs detection. For example, ethanol detection has been achieved at 300 °C using a YX LiTaO 3 -based SAW sensor modified with a ZnO intermediate layer of 1.2 μm and a WO 3 sensing layer of 150 nm [ 177 ]; porous ZnO-SiO 2 bilayer nano-films have been used for NH 3 detection, with SAW sensor sensitivity being better than the one for single layers and was found to be dependent on bi-film conductivity [ 178 ].…”

“…CNTs, SWCNTs, and MWCNTs dispersed in ethanol or toluene for example, have been separately tested for ethanol, toluene, and ethyl acetate sensing at RT with a LOD of 1 ppm [ 184 ]. The main advantage of CNTs-modified sensors is the enhanced SAW sensor-sensitivity, due to the ability to sense variations not only in mass but also in conductivity [ 172 ].…”

Detection of Covid-19 through a Heptanal Biomarker Using Transition Metal Doped Graphene

“… 8 For instance, the breath of patients infected with tuberculosis (TB) shows increased levels of several benzene and aldehyde derivatives, 10 and acetone is highly related to diabetes detection. 11 Using VOCs to detect various diseases and metabolic disorders such as cancers, kidney failure, liver disease, and Alzheimer’s disease has been studied in the past, 9 , 12 − 14 and a similar approach has been recently expanded to include COVID-19 diagnosis. 5 , 15 , 16 From studies conducted by Berna et al 5 and Miller et al., 16 heptanal has been identified as one of the key biomarkers which was significantly elevated in the breath of SARS-CoV-2 patients.…”

“…There are several major technologies in VOC detection, including gas chromatography–mass spectrometry (GCMS) and chemo-resistive devices, as well as sensor-based diagnosis. 11 Recognized as the gold standard, GC-MS has been widely used in clinical trials in breath VOC detection. 17 , 18 However, it is time-consuming and requires bulky, expensive equipment and highly trained professionals.…”

Ionic Liquid-Based Quartz Crystal Microbalance Sensors for Organic Vapors: A Tutorial Review

“…Here, we provide a comprehensive review of the rapidly growing scientific literature on the development of IL-coated QCM sensors/sensor arrays and their applications for the analysis of complex mixtures of VOCs. Interested readers are referred to recently published reviews that cover other QCM sensing materials [39][40][41][42][43]. This manuscript summarizes: (i) The working principle of QCM and QCM-D (quartz crystal microbalance with dissipation monitoring); (ii) ILs and their characteristic properties that make them suitable sensing materials for QCM; (iii) recent advances in IL-coated QCM sensors and multi-sensor arrays; and (iv) recent advances in IL-coated virtual sensor arrays and their applications.…”