Electropolymerized molecularly imprinted polymers (E-MIPs) on disposable electrodes for rapid sub-nanomolar protein determination in serum AN Stephen 1 , SR Dennsion 2, MA Holden 1 , SM Reddy 1 1 Department of Chemistry, University of Central Lancashire, UK, 2 School of Pharmacy and Biomedical Sciences, University of Central Lancashire, UK Molecularly imprinted polymers (MIPs) are a rapidly evolving class of synthetic receptor with antibody-like affinities. They are low-cost, selective, and biocompatible materials. MIPs are produced in one chemical step and are highly stable even at room temperature. This contrasts with biological antibodies which are produced in an immunised animal host, could take months to produce, if produced at all; and have limited stability. MIPs therefore offer multiple advantages as an antibody replacement technology. The potential applications of MIPs are in diagnostics, bioseparation and therapeutics. We investigated electropolymerized molecularly imprinted polymers (E-MIPs) for the selective biosensing of model proteins. We evaluated different disposable gold screen-printed electrodes. E-MIPs imprinted with haemoglobin (BHb) and bovine serum albumin (BSA) were electrochemically deposited onto the screen printed electrodes by reductive electropolymerization, using N-hydroxmethylacrylamide (NHMA) as functional monomer and crosslinked with N,N’-methylenebisacrylamide (MBAm). Using cyclic voltammetry and electrochemical impedance spectroscopy analysis, E-MIPs for BHb demonstrated an imprinting factor of 146:1 at 1nM and 12:1 at 0.1nM when tested in the nanomolar range. The BHb E-MIP, when tested against BSA as non-specific protein gave a high selectivity factor of 6:1. We found that the sensor sensitivity directly depended on the nature of the screen-printed electrode, demonstrating limits either in the sub-micromolar or picomolar range for target protein. We attribute this to differences in electrode annealing temperature, electrode surface area and electrode crystallinity between the electrodes studied. The E-MIPs were also tested in calf serum as a model biological sample. The SPE-MIPs detected the presence of target protein in < 10 min with a limit of detection of 0.1 nM, suggesting their suitability for protein determination in serum with minimal sample preparation. We anticipate such MIPs will be used in immunodiagnostics for a range of biologically relevant protein-based disease biomarkers such as in cancer and autoimmune diseases.
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© The Author(s), 2023
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