Chemoresistive Gas Sensors for the Detection of Colorectal Cancer Biomarkers

Abstract

Numerous medical studies show that tumor growth is accompanied by protein changes that may lead to the peroxidation of the cell membrane with consequent emission of volatile organic compounds (VOCs) by breath or intestinal gases that should be seen as biomarkers for colorectal cancer (CRC). The analysis of VOCs represents a non-invasive and potentially inexpensive preliminary screening technique. An array of chemoresistive gas sensors based on screen-printed metal oxide semiconducting films has been selected to discriminate gases of oncological interest, e.g., 1-iodononane and benzene, widely assumed to be biomarkers of colorectal cancer, from those of interference in the gut, such as methane and nitric oxide.

Detection of colorectal cancer biomarkers in the presence of interfering gases

“…However, it can be noticed that the TiTaV sensor (titanium, tantalum, vanadium oxides) was not sensitive to it, and it showed a great selectivity to small quantities of C 6 H 6 even in the presence of hydrogen. This confirms the good capability of TiTaV to detect benzene only [1] or in presence of interferers (Figs. 9 and 10).…”

“…14, the ZnO 850 sensor (zinc oxide, fired at 850 • C) and STN (tin, tantalum, niobium oxides) are the ones that give the best responses to this compound, confirming results for tin oxidebased sensors of a previous work [1], in wet conditions. Humidity does not change the trend of the responses to 1-iodo-nonane but reduces only their value.…”

“…Nano-materials can offer promising non-invasive methods to detect and prevent cancer [1]. It is known that VOCs emissions, produced by the peroxidation of the cell membrane or by cellular metabolism, are linked to tumor presence and growth and they can be detected directly from the headspace of cancer cells or through exhaled breath [2,3].…”

“…The scheme of the experimental setup is shown inFig. 5published in our previous work Malagù et al[1].…”

Use of Gas Sensors and FOBT for the Early Detection of Colorectal Cancer

“…Therefore, the importance of an additional screening system lies in the decrease of false positive rate, to reduce the number of non-operative colonoscopies, risky for elderly and debilitated patients. Previous works by our team have shown that chemoresistive sensors are capable of detecting tumor biomarkers in very low concentrations (tenths of ppb) [3,4]. The technique presented here employs a patented device [5] named SCENT A1, made of a core of five chemoresistive sensors.…”