Amperometric glucose biosensing performance of a novel graphene nanoplatelets-iron phthalocyanine incorporated conducting hydrogel

Herein, a novel one step synthesis of multicomponent three dimensional polyacrylic acid (PAA) based conducting hydrogel (CH) incorporated with iron phthalocyanine functionalised graphene nanoplatelets (GPL-FePc) is reported. An amperometric glucose biosensor was fabricated by the immobilization of glucose oxidase (GOx) onto the synthesised PAA-VS-PANI/GPL-FePc-CH (where VS-PANI is vinyl substituted polyaniline). Scanning electron microscopy reveals the presence of three dimensional microporous structure with estimated pore size of 19 μm. The 5-(trifluoromethyl)-2-mercaptopyridine substitution onto FePc enabled the solubility of FePc in water and controls the aggregation of GPL-FePc in the synthesised CH. A sharp peak around 699 nm in UV–visible spectra confirms the presence of incorporated GPL-FePc into CH. Cyclic voltammogram of the synthesised CH biosensor exhibited well defined redox peaks with a ΔEp value of 0.26 V in Fe(CN)6 3-/4- bench mark solution. The fabricated PAA-VS-PANI/GPL-FePc/GOx-CH amperometric biosensor resulted in remarkable detection sensitivity of 18.11 μA mM−1 cm−2 with an average response time of ∼1 s, linearity from 1 to 20 mM, and low detection limit of 6.4 μM for the determination of glucose.