Influence of Water Molecules on the Detection of Volatile Organic Compounds (VOC) Cancer Biomarkers by Nanocomposite Quantum Resistive Vapor Sensors vQRS

Abstract

The anticipated diagnosis of various fatal diseases from the analysis of volatile organic compounds (VOC) biomarkers of the volatolome is the object of very dynamic research. Nanocomposite-based quantum resistive vapor sensors (vQRS) exhibit strong advantages in the detection of biomarkers, as they can operate at room temperature with low consumption and sub ppm (part per million) sensitivity. However, to meet this application they need to detect some ppm or less amounts of biomarkers in patients' breath, skin, or urine in complex blends of numerous VOC, most of the time hindered by a huge amount of water molecules. Therefore, it is crucial to analyze the effects of moisture on the chemo-resistive sensing behavior of carbon nanotubes based vQRS. We show that in the presence of water molecules, the sensors cannot detect the right amount of VOC molecules present in their environment. These perturbations of the detection mechanism are found to depend on the chemical interactions between water and other VOC molecules, but also on their competitive absorption on sensors receptive sites, located at the nanojunctions of the conductive architecture. This complex phenomenon studied with down to 12.5 ppm of acetone, ethanol, butanone, toluene, and cyclohexane mixed with 100 ppm of water was worth to investigate in the prospect of future developments of devices analysing real breath samples in which water can reach a concentration of 6%.

Emerging Strategies Based on Sensors for Chronic Wound Monitoring and Management

“…Subsequently, the vQRSs were mounted into an array (e-nose) for analysis of the VOCs released from the PU [97,98]. The vQRSs were exposed to concentrations ranging from ppm to ppb of three VOC biomarkers and water vapor to assess their selectivity and sensitivity [99]. The preliminary results exhibited that the e-nose was able to discriminate between artificial vapor cocktails made of different proportions of biomarkers and water molecules.…”

Boosting Selectivity and Sensitivity to Biomarkers of Quantum Resistive Vapour Sensors Used for Volatolomics with Nanoarchitectured Carbon Nanotubes or Graphene Platelets Connected by Fullerene Junctions

“…To go further it will be necessary to assemble more than 10 different vQRS of different selectivities into an array (e-nose) and to classify their responses with an algorithm such as PCA to be able to discriminate the different VOC into a 2D map, which was done there [59,87,88]. Another step consists of checking the influence of water molecules on the detection of biomarkers, as breath contains more than 80% moisture, which was done previously [89]. Therefore, it is believed that if sensors are not very sensitive to water, this drawback can be compensated by including a vQRS with a much higher sensitivity to water, such as chitosan functionalized CNT, for instance [70,87,88], in the e-nose.…”

Dielectric behavior of thin films of unsaturated polyester‐resin/carbon nanotube semiconductor composites

“…[1][2][3][4][5][6][7][8] High sensitivity, selectivity and repeatability are essential characteristics for resistive capacitor gas sensor production as well as appropriate detection limit, low cost, and tolerance for a variety of chemical background demands, such as humidity. [9][10][11] Carbon nanotube (CNT)-based composites have been reported to exhibit vapor sensitivity to several gases, including organic solvents.…”