Preparation, Interaction Mechanism and Application of Functional Ionic Liquid-Mediated Protein Imprinting Technique

Protein recognition underpins advances in drug discovery, immunoassays, clinical diagnostics and biosensing. As a biomimetic alternative to natural receptors, molecularly imprinted polymers (MIPs) have been developed to emulate antibody–antigen complementarity by generating binding cavities that mirror the size, shape and functionality of target macromolecules through template-directed polymerization and subsequent template removal. However, protein imprinting has historically been hampered by low imprinting efficiency and limited selectivity, rendering conventional protein-imprinted polymers (PIPs) inadequate for many contemporary biomedical applications. Functional ionic liquids (ILs)—a class of designer solvents and materials distinguished by tunable structures, exceptional physicochemical properties and favorable biocompatibility—have emerged as versatile additives to address the principal limitations of traditional PIPs, including poor selectivity, sluggish mass transfer and destabilization of protein conformation. Here, we provide a systematic review of the multifaceted roles that ILs play within protein-imprinting systems, delineating their employment as template-anchoring motifs, functional monomers, cross-linkers, porogens and structural stabilizers, and evaluating the consequent effects on polymer architecture and recognition performance. We further probe the multiplicity of non-covalent interactions between ILs and template proteins—highlighting the synergistic modulation afforded by electrostatic forces, hydrogen bonding, hydrophobic interactions and π-π stacking—and consider how such interplay can be harnessed to fine-tune binding-site fidelity. Consolidating recent progress, we summarize IL-enabled PIP applications in protein-specific recognition, biosensor development and analysis of complex real-world samples, and we critically examine the prevailing technical challenges and prospects for translation. The evidence indicates that ILs, by furnishing abundant interaction sites, accelerating mass transport and stabilizing native protein conformations, can markedly enhance PIP adsorption capacity, target specificity and recyclability, positioning them as a cornerstone for next-generation protein separation and enrichment materials and paving the way toward industrial deployment of protein-imprinting technologies.