Electrospinning of graphene-oxide onto screen printed electrodes for heavy metal biosensor

We present an electrospinning of graphene-oxide (GO) onto screen printed carbon electrodes (SPCE) for heavy metals (HMs) bio-sensing. The GO was dispersed in poly (vinyl alcohol) (PVA) diluted aqueous solution, and the mixture was electrospun into GO/PVA composite nanofibers. The morphology of GO and SPCE modified with electrospun nanofiber was studied using SEM micrographs and confirmed the uniform distribution of GO sheets in nanofibers. The Alkaline Phosphatase (ALP) was immobilized onto nanofibers grown on the SPCE and activity was checked using 1-napthyl phosphate (1-NP) by applying differential pulse voltammetry (DPV). The ALP activity was inhibited in the presence of HMs and a difference in activity was recorded after inhibition. The inhibition was calculated based on the data of pre and post inhibition current values. The inhibition of ALP was observed with mercury (Hg²⁺), lead (Pb²⁺) and cadmium (Cd²⁺) with a detection limit of 0.0075, 0.015 and 0.0312 ppb respectively. The developed biosensor was also tested to evaluate the matrix suitability through recovery studies. Excellent HM recoveries were obtained in the range 94.6–99.75 with%RSD value of 3.77.