Synthesis of water-soluble and cross-linkable ferrocenyl redox polymers for uses as mediators in biosensors

A series of ferrocenyl redox polymers to be used as electron transfer mediators in biosensors were synthesized. Ferrocene loading in the redox polymers varied from 3 to 14%, depending on the polymerization conditions. Flourier transform infrared (FT-IR) and UV–visible (UV–vis) spectrophotometry were performed to confirm the presence of the monomeric units in the redox polymers and the saturated character of the synthesized redox polymers. Gel permeation chromatographic technique was applied to reveal the molecular weights of the redox polymers. The redox polymers were cross-linkable with proteins. For example, glucose oxidase and the redox polymers were cross-linked using poly(ethylene glycol) diglycidyl ether and bovine serum albumin (BSA), forming stable and highly effective biosensing membranes on an electrode surface. The electron-mediating efficiency of the redox polymers was assessed using cyclic voltammetry, based on the sensitivity of catalytic oxidation of glucose and reproducibility of the results obtained.