An e-nose made of carbon nanotube based quantum resistive sensors for the detection of eighteen polar/nonpolar VOC biomarkers of lung cancer

Abstract

A room temperature operating electronic nose (e-nose) has been developed by the assembly of conductive polymer nanocomposite (CPC) quantum resistive sensors (QRS). The fabrication of QRS by spray layer by layer (sLbL) of CPC solutions allowed us to obtain transducers with reproducible initial properties that could be easily tailored by adjusting either the number of sprayed layers and/or the solution composition. The selectivity of QRS was varied by changing the chemical nature of the polymer matrix in which carbon nanotubes (CNTs) were dispersed in solution, i.e., poly(carbonate) (PC), poly(caprolactone) (PCL), poly(lactic acid) (PLA), poly(styrene) (PS), and poly(methyl methacrylate) (PMMA). The e-nose was then successfully used to detect several volatile organic compounds (VOCs) selected among lung cancer biomarkers: a first set of seven polar vapours (water, ethanol, methanol, acetone, propanol, isopropanol, and 2-butanone), and another set of eleven less and nonpolar vapours (chloroform, toluene, benzene, styrene, cyclohexane, o-xylene, n-propane, n-decane, 1,2,4-trimethyl benzene, isoprene, and 1-hexene). The discrimination ability of the e-nose evaluated after a 3D principal component analysis (PCA) pattern recognition treatment was proved to be very good. Moreover, the quantitativity of the transducers' chemo-resistive responses was well fitted with the Langmuir-Henry-Clustering (LHC) model for both acetone and toluene vapours in a wide range of concentrations. The QRS developed in this study appear to be very good candidates to design low cost e-noses for the anticipated diagnosis of lung cancer by VOC analysis in breath, with ppm level sensitivity (tested down to 2.5 parts per million), short response time (a couple of seconds), low consumption, and a large signal to noise ratio (SNR $ 10).

Reduced Water Permeability of Biodegradable PCL Nanocomposite Coated Paperboard Packaging

“…2(b)), it can be assumed that they form higher interactions with paperboard than with PCL, which results in the presented morphology. All changes in the PCL nanocomposite coatings morphology can reflect in the properties of the coated paperboard packaging, like mechanical properties, barrier properties, and changes in the print color, but despite such aggregation and due to the low concentration, this type of dispersion can still contribute to the enhancement of barrier and mechanical properties 16 .…”

vQRS Based on Hybrids of CNT with PMMA-POSS and PS-POSS Copolymers to Reach the Sub-PPM Detection of Ammonia and Formaldehyde at Room Temperature Despite Moisture

“…The two different selected vQRS, PS-co-POSS/CNT and PMMA-co-POSS/CNT, were exposed to CH 2 O nitrogen/analyte successive cycles of 5 min in order to interpret the responses collected in Figure 5a. The shape of the two curves appears very typical of the LHC model developed to fit the evolution of the chemo-resistive response with the concentration of the analyte and is expressed in Equation (6) [23,79,80]. The LHC model also allows deducing whether penetrating solvent vapour molecules will only slightly adsorb on specific sites (Langmuir), diffuse and form of several layers of vapour molecules on CPC (Henry), or generate plasticization and swelling of the matrix through the clustering of solvent vapour molecules (Clustering).…”

Core-shell nanostructured hybrid composites for volatile organic compound detection

“…The sensor arrays based on the hybrid PEDOTPIL@Fe 3 O 4 channel materials exhibited high sensitivity (1 ppm concentration) to VOC biomarkers including methanol, ethanol, acetone, benzene, and toluene, which are present in the exhaled breath of lung cancer patients. [6][7][8][9] The sensors also exhibited a high stability with a low level of noise, …”

“…This method also has the potential to diagnose lung cancer at an early stage by detecting volatile organic compound (VOC) biomarkers in exhaled breath. [6][7][8][9] As such, a number of breath-analysis tools have been developed including gas chromatography/mass spectrometry, [10][11][12][13][14] ion flow tube mass spectrometry, 15,16 chemo-luminescence sensors, 17 optochemical fibers, 18 infrared spectroscopy, 19 and polymer-coated surface acoustic wave sensors. 20 Incorporating most of the conventional breath analysis techniques into portable sensing devices is difficult, however, owing to the bulky and expensive nature of these instruments and complexity of their operation.…”