Synthesis of uniformly sized molecularly imprinted polymer-coated silica nanoparticles for selective recognition and enrichment of lysozyme

Abstract

Combining surface imprinting with nanomaterials is an effective solution to overcome template removal and achieve large binding capacity. In this work, highly monodisperse and uniform-sized silica nanoparticles (NPs) with average diameter of ∼400 nm were synthesized by using tetraethoxysilane (TEOS) as a single precursor, and then vinyl groups were introduced onto the surface of silica NPs by chemical modification of γ-methacryloxypropyltrimethoxysilane (γ-MAPS). Subsequently, the molecularly imprinted polymer (MIP) coating was copolymerized and anchored onto the surface of vinyl modified silica NPs dispersed in aqueous media with lysozyme (Lyz) as a template. The morphology and structure property of the resultant MIP-coated silica NPs were characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The polymerization and adsorption conditions were investigated in detail in order to obtain the highest selectivity and binding capacity. Under the optimized conditions, the imprinted nanoparticles showed higher binding affinity toward the template than non-imprinted (NIP) nanoparticles, and the corresponding imprinted factor (a) reached 1.68. The specificity for Lyz recognition was evaluated with competitive experiments, indicating the imprinted nanoparticles have a higher selectivity for the template. The resultant Lyz-MIP silica NPs could not only selectively extract a target protein from mixed proteins, but also specifically enrich Lyz from human serum. In addition, the stability and regeneration were also investigated, which indicated the imprinted silica NPs had excellent reusability.