Electrochemical probing of selective haemoglobin binding in hydrogel-based molecularly imprinted polymers

Abstract

An electrochemical method has been developed for the probing of hydrogel-based molecularly imprinted polymers (HydroMIPs) on the surface of a glassy carbon electrode. HydroMIPs designed for bovine haemoglobin selectivity were electrochemically characterized and their rebinding properties were monitored using cyclic voltammetry. The electrochemical reduction of bovine oxyhaemoglobin (BHb) in solution was observed to occur at -0.460 V vs (Ag/AgCl) in 150mM phosphate buffer solution (PBS). When the protein was selectively bound to the MIP, the electrochemical reduction of oxyhameoglobin could be observed at a similar peak potential of -0.480 V vs (Ag/AgCl). When analysing the non-imprinted control polymer (NIP) interfaced at the electrode, which contained no protein, the peak reduction potential corresponded to that observed for dissolved oxygen in solution (-0.65 V vs (Ag/AgCl)). MIP and NIP (in the absence of protein) were interfaced at the electrode and protein allowed to diffuse through the polymers from the bulk solution end to the electrode. It was observed that whereas NIP exhibited a protein response within 10 minutes of protein exposure, up to 45 min of exposure time was required in the case of the MIP before a protein response could be obtained. Our results suggest that due to the selective nature of the MIP, BHb arrival at the electrode via diffusion is delayed by the MIP due to attractive selective interactions with exposed cavities, but not the NIP which is devoid of selective cavities.

Smart plastic antibody material (SPAM) tailored on disposable screen printed electrodes for protein recognition: Application to myoglobin detection

“…Antibody-based immunoassays are the most commonly used diagnostic tool for the analysis of biomolecules (Borrebaeck, 2000;Katz and Davis, 2000;Reddy et al, 2011;Rimmer, 1998). This is due to the great selectivity and affinity linked to the antibody-antigen reactions observed in nature.…”

Enzymes as Tools in MIP-Sensors

“…Two major principles have been applied: (i) Electroactive targets, such as morphine, paracetamol, tamoxifen, and diclofenac can permeate through the cavities of the MIP to the electrode and an electrochemical signal can be generated by the conversion of the target using different electrochemical methods. This principle has been frequently used for drugs which contain phenolic structures but also for a few proteins which show direct electron transfer, e.g., cytochrome c, hemoglobin, and hexameric tyrosinecoordinated heme protein (HTHP) [21,70,71]. (ii) Binding of the target modulates the diffusive permeation of redox markers in a concentrationdependent manner.…”

Backside-surface imprinting as a new strategy to generate specific plastic antibody materials

“…[10][11][12] Size, complexity, conformational exibility and solu-bility of proteins are main obstacles, which have been surpassed by using bulk, epitopes or surface imprinting approaches. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] Surface imprinting seems by far the most successful approach in plastic Ab design. It consists mostly in attaching the template to the surface, enabling a pre-polymerization stage where functional monomers are allowed to bind to the template molecule, and polymerize the monomeric material by controlled/living free radical polymerization.…”