Specific recognition of a target protein, cytochrome c, using molecularly imprinted hydrogels

Protein imprinted hydrogel, which is one form of protein imprinted molecularly imprinted polymer (MIP), is an important material for enzyme-linked immunosorbent assay, drug delivery materials, sensors, separation materials, etc. To obtain a high protein recognition performance, it is essential to optimize the involved compositions. This work studies a copoly(poly(ethylene glycol) diacrylate/poly(ethylene glycol) acrylate), in short copoly(PEGDA/PEGA), based MIP hydrogel targeting cytochrome c recognition. The presented MIP hydrogel employs water-soluble PEGDA as the crosslinker, PEGA as the side chain, and sodium allylsulfonate as the functional monomer. The fabricated MIP hydrogels and non-imprinted polymer (NIP) hydrogels were treated as adsorbents for protein adsorption. Efforts were made targeting an optimized recognition performance. Factors including the template to functional monomer ratio, crosslinker length, crosslinker ratio of PEGDA/PEGA, ionic strength in the adsorption test, and presence of acidic modifier in the adsorption test were investigated. The results showed that a higher template to functional monomer ratio, a shorter crosslinker, and additional NaCl (20 mM) in the adsorption solvent provided a higher imprinting factor. A lower crosslinker ratio of no less than 6/4 offered a faster template removal; at the same time, the imprinting factor remained at a quite high level. Highly specific recognition of cytochrome c was realized with the presence of an optimized amount of HCl (10 mM) as an acidic modifier.