Solid-phase engineering of molecularly imprinted nanoparticles (NanoMIPs): how template and solid-phase drive polymer composition and binding performance

Molecularly imprinted polymer nanoparticles (nanoMIPs) represent a promising class of synthetic recognition elements with growing potential as robust alternatives to antibodies in diagnostic and sensing technologies. Despite widespread use, limited attention has been given to how solid-phase synthesis parameters, particularly the nature of the solid support and template identity, affect nanoMIP composition and function. Herein, we present a systematic investigation comparing popular glass bead and magnetic nanoparticle solid-phase protocols for nanoMIP synthesis targeting protein templates bovine haemoglobin (BHb) and bovine serum albumin (BSA). Using an identical functional monomer feed and surface plasmon resonance (SPR)-based affinity assays, we demonstrate that the choice of solid-phase significantly influences particle size, yield, and binding affinity, with nanoMIPs synthesized on glass beads exhibiting up to a tenfold enhancement in binding performance compared to those produced on magnetic nanoparticles. Furthermore, 1H NMR analysis reveals substantial deviations between initial monomer feed ratios and final polymer compositions, with polymer structure being highly dependent on both the solid phase and template characteristics. These findings highlight the importance of rational nanoMIP design, by challenging assumptions of uniform polymer composition and revealing how template and solid-phase interactions shape material properties. Our work establishes a framework for engineering high-performance synthetic receptors with tuneable properties and offers key insights for the optimisation of nanoMIP-based applications and sets new benchmarks for material consistency, reproducibility, and potential commercialisation.