Development of a Reusable Transducer Matrix Based on Nano Structured Conducting Polyaniline and Its Application to Cholesterol Biosensor

Nanostructured conducting polyaniline (S1I3) film, was electrodeposited on indium tin oxide coated glass plate (ITO) using cyclic voltammetric technique from chemically synthesized NSPANI dispersion. The electrodeposited S1I3 nano film was used for covalent immobilisation of cholesterol oxidase (ChOx) and cholesterol esterase (ChEt) via glutaraldehyde as a cross-linker for the estimation of free as well as total cholesterol. The nanobioelectrodes ChOx/S1I3/ITO and ChEt ChOxt/S1I3/ITO have been characterised by linear sweep voltammetery (LSV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The nanobioelectrodes exhibit excellent repeatability and uniform bioactivity for 20 weeks with 100% of efficiency under refrigerated conditions. The values of enzymes kinetic parameter (Michelis-Menten constant, K-m) for ChOx/S1I3/ITO and ChEt ChOx/S1I3/ITO bioelectrode was 0.85 and 0.357 mM respectively using Lineweaver-Burke Plot indicate high affinity of ChOx to cholesterol and ChEt, ChOx to cholesterol oleate. The ChOx/S1I3/ITO, ChEt ChOx/S1I3/ITO nanobioelectrodes can be reused for number of times. The unique features of the developed cholestetol nanobioelectrode lie on their reusability and very high shelf life apart from the very low K-m value, low response time and high sensitivity.