Tunable Gas Sensing Gels by Cooperative Assembly

Abstract

The cooperative assembly of biopolymers and small molecules can yield functional materials with precisely tunable properties. Here, the fabrication, characterization, and use of multicomponent hybrid gels as selective gas sensors are reported. The gels are composed of liquid crystal droplets self-assembled in the presence of ionic liquids, which further coassemble with biopolymers to form stable matrices. Each individual component can be varied and acts cooperatively to tune gels' structure and function. The unique molecular environment in hybrid gels is explored for supramolecular recognition of volatile compounds. Gels with distinct compositions are used as optical and electrical gas sensors, yielding a combinatorial response conceptually mimicking olfactory biological systems, and tested to distinguish volatile organic compounds and to quantify ethanol in automotive fuel. The gel response is rapid, reversible, and reproducible. These robust, versatile, modular, pliant electro-optical soft materials possess new possibilities in sensing triggered by chemical and physical stimuli.

Identification of a biomarker panel for improvement of prostate cancer diagnosis by volatile metabolic profiling of urine

“…26 In line with this, a biomarker panel was herein defined consisting in the combination of 6 discriminatory metabolites. A small panel of biomarkers was selected in this work envisaging the development of a sensing material 27 tuned in specificity and selectivity for these compounds to be applied in an “e-nose” in near future. This 6-biomarker panel unveiled good prediction of PCa from non-cancer patients, providing accuracies of 79% and 86% in the internal and external sets, respectively.…”

Microfluidics in Gas Sensing and Artificial Olfaction

“…There, the interaction of the sample’s VOC molecules with the sensing materials generates signals that are transduced and processed by a computing unit. In the last decade, much work has been devoted to the development of optimized gas-sensors [ 5 , 20 , 21 , 22 ], signal processing [ 23 ], and device architectures [ 24 , 25 ], always targeting the ideal of a compact, miniaturized e-nose with accurate and selective performance. In particular, important effort has been put on the optimization of the sample preparation and delivery system.…”

Thermotropic Liquid Crystal-Assisted Chemical and Biological Sensors

“…The unique combination of LC responsiveness to the environment and the striking optical effects that allow the rapid visualization of this response facilitates the use of LCs in sensing applications. The LC responds to several different classes of molecules, including surface-active agents such as lipids and surfactants [ 5 , 6 , 7 , 8 , 9 ] and non-surface-active molecules such as gas vapors [ 10 , 11 , 12 , 13 ] and can be tailored to respond only to specific antigens [ 9 , 10 , 14 , 15 , 16 , 17 ].…”