A flexible-imprinted capacitive sensor for rapid detection of adrenaline.

This article demonstrates a non-enzymatic biomimetic adrenaline capacitive sensor fabricated inexpensively by layer-by-layer (LbL) assembly. The LbL assembly consists of polydimethylsiloxane (PDMS) substrate, carbon nanotube-cellulose nanocrystals (CNC/CNT) nanofilms (first layer) with adrenaline imprinted poly (aniline/phenylboronic acid) (pANI/PBA) moieties (second layer). The flexible sensor has been effectively demonstrated for high sensitivity and selectivity in capacitive detection of adrenaline standard and adrenaline in real zebra fish brain sample. The molecularly imprinted adrenaline sensor exhibited linear response between 0.001  μM and 100  μM with a correlation coefficient of 0.9738 and detection limit (LOD) of 0.001  μM. The developed sensor demonstrated high adrenaline selectivity and good sensor to sensor reproducibility of 15.7% for molecularly imprinted films. The sensor precision for triplicate standard runs for different adrenaline concentrations ranged from 0.5 to 5.0%, indicative of the overall reliability and validity of the device. The inexpensive sensor remains stable over time, responding proportionately to doses of adrenaline, and as such effective as a dosimetric sensor for near real time continuous monitoring. Frugal in sample consumption (50 μL), the study suggested the practical utilization of the developed biosensor towards adrenaline detection in biological fluids.