Application of thymine-based nucleobase-modified acrylamide as a functional co-monomer in electropolymerised thin-film molecularly imprinted polymer (MIP) for selective protein (haemoglobin) binding

Molecularly imprinted polymers (MIPs) are fast becoming alternatives to biological recognition materials, offering robustness and the ability to work in extreme environments. Here, a modified thymine-based nucleobase, with acrylamide at the 5-postion (AA-dT) was used as a co-monomer in the synthesis of a thin-film electropolymerised MIP system for the molecular recognition of the protein haemoglobin. The AA-dT co-monomer incorporated into a N-hydroxymethylacrylamide (NHMAm) MIP offered a two-fold superior binding affinity of the NHMAm only MIP, with KD values of 0.72 μM and 1.67 μM, respectively. A unique AA-dT:NHMAm MIP bilayer was created in an attempt to increase the amount AA-dT incorporated into the film, and this obtained a respectable KD value of 7.03 μM. All MIPs produced excellent selectivity for the target protein and when applied to a sensor platform (Surface Plasma Resonance), the limit of detection for the MIPs is in the nM range (3.87, 3.47, and 3.87 nM, for the NHMAm MIP, AA-dT:NHMAm MIP, and AA-dT:NHMAm MIP bilayer, respectively). The introduction of the modified thymine-based nucleobase offers a promising strategy for improving the properties of a MIP, allowing these MIPs to potentially be a highly robust and selective material for molecular recognition.