ZnO nanorods bonded polythiophene nanocomposite: an enhanced electrochemical voltammetric biosensing of L-tryptophan

Electrostatically fused nanocomposite of zinc oxide (ZnO) nanorods affixed with polythiophene (PT) was successfully illustrated for effective voltammetric biosensing of L-tryptophan (L-Try) in this work. Structural characterization confirms the in-situ composite formation of PT @ ZnO and its BET analysis reveals the porous nature of as-synthesized material having the specific surface area of 4.953 m2 g–1 and average pore diameter of 2.153 nm, respectively. PT @ ZnO exhibits superior electrochemical performance towards L-Try in phosphate buffer solution of pH 7 by the movement of fast electron-transfer rate because of effective interaction between indole group of L-Try and PT @ ZnO nanocomposite. That is, the sulphur group in PT easily attached with the amine group of L-Try demonstrated the linear increase of peak current with increasing concentration in the range of L-Try 100 nM–1 mM having detection limit of 8.5 nM. The invented biosensor shows extraordinary selectivity among other physiological substances and also exposes high stability, repeatability and reproducibility. The practical utility of PT-ZnO/glassy carbon electrode tested with the concentration of L-Try in peanut extract showed preferable results. Graphical Abstract