Novel electro-polymerized protein-imprinted materials using Eriochrome black T: Application to BSA sensing

Abstract

A novel material produced in-situ by electropolymerization of Eriochrome black T (EBT) is presented for the first time to produce a molecularly-imprinted polymer (MIP) tailored for protein recognition. This monomer is particularly useful because it contains in the same structure different functions that may interact with different sites within the same protein (by ionic interaction of hydrogen bonding). The polymer was poly(EBT) (PEBT) and was obtained by applying on a carbon support a suitable range of potential values, established by cyclic voltammetry (CV) along consecutive cycles. In a parallel approach, the carbon support was modified by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) prior to the MIP synthesis, thereby yielding a substrate of better electrical properties and checking this effect upon the resulting biosensor.The two above approaches used BSA as model target protein. The polymeric material acted as a plastic antibody for BSA and was obtained through a bulk imprinting strategy, by electropolymerizing EBT in a solution that also contained the target protein. The chemical features were followed by Raman spectroscopy while the electrical properties were followed by electrochemical impedance spectroscopy (EIS). The electrical properties tested were the stability of polymeric film within time, the main analytical features of the calibration curves under different media and the selectivity properties. The thermal stability was also tested by thermogravimetric assays.Overall, the novel polymeric film displayed good thermal and storage stabilities, which are fundamental features in biosensor development. Both MIP and MIP-PEDOT displayed linear responses over a wide range of concentrations and similar detection limits. The MIP-PEDOT material was 9 × more sensitive to the presence BSA concentration. The analytical responses of the biosensor to spiked serum confirms the promising features of the described approach.