A chemical-detecting system based on a cross-reactive optical sensor array

Abstract

The vertebrate olfactory system has long been recognized for its extraordinary sensitivity and selectivity for odours. Chemical sensors have been developed recently that are based on analogous distributed sensing properties, but although an association between artificial devices and the olfactory system has been made explicit in some previous studies, none has incorporated comparable mechanisms into the mode of detection. Here we describe a multi-analyte fibre-optic sensor modelled directly on the olfactory system, in the sense that complex, time-dependent signals from an array of sensors provide a 'signature' of each analyte. In our system, polymer-immobilized dye molecules on the fibre tips give different fluorescent response patterns (including spectral shifts, intensity changes, spectral shape variations and temporal responses) on exposure to organic vapours, depending on the physical and chemical nature (for example, polarity, shape and size) of both the vapour and the polymer. We use video images of temporal responses of the multi-fibre tip as the input signals to train a neural network for vapour recognition. The system is able to identify individual vapours at different concentrations with great accuracy. 'Artificial noses' such as this should have wide potential application, most notably in environmental and medical monitoring.

Origin and prediction of free-solution interaction studies performed label-free

“…Testing the validity of FreeSRF. As with other models (37,(69)(70)(71)(72), it was necessary to use a learning set to establish the appropriate relationships and weighting parameters for FreeSRF. In our case, we determined χ from ρ exp for a training set of well-characterized binding systems (Table 1).…”

Exploitation of spatiotemporal information and geometric optimization of signal/noise performance using arrays of carbon black-polymer composite vapor detectors

“…Detector types of interest include carbon black-insulating polymer composites [1], conducting organic polymers [2][3][4], polymer-coated quartz crystal microbalances (QCM) [5], polymer-coated surface acoustic wave (SAW) devices [6,7], polymer-coated capacitors [8], and arrays of dye-impregnated polymeric beads or coated optical fibers [9][10][11]. The responses of such sorption-based detectors depend primarily on the partition coefficient of the gaseous analyte into the polymer [12].…”

Synthesis, structure, optoelectronic properties of novel zinc Schiff-base complexes

“…Some of the Schiff-base complexes possess interesting nonlinear optical [5,6] and magnetic properties [7,8]. On the other hand, fluorescent complexes have been extensively studied mainly because they may be good candidates for fluorescent sensors and electroluminescent (EL) devices [9,10]. Zinc Schiff-base complexes exhibited strong electroluminescence as well as photoluminescence [1113] which are strongly coupled to molecular structures and bulk molecular packing characteristics [14,15].…”