Surface-Imprinted Core—Shell Nanoparticles for Sorbent Assays.

In this paper, we present a general protocol for the making of surface-imprinted core—shell nanoparticles via surface reversible addition-fragmentation chain—transfer (RAFT) polymerization using RAFT agent functionalized model silica nanoparticles as the chain-transfer agent. In this protocol, trichloro(4-chloromethylphenyl)silane was immobilized on the surface of SiO2 nanoparticles, forming chloromethylphenyl functionalized silica (silica-Cl). RAFT agent functionalized silica was subsequently produced by substitute reaction of silica-Cl with PhC(S)SMgBr. The grafting copolyinerization of 4-vinylpyridine and ethylene glycol dimethacrylate using surface RAFT polymerization and in the presence of 2,4-dichiorophenoxyacetic acid as the template led to the formation of surface-imprinted core—shell nanoparticles The resulting surface-imprinted core—shell nanoparticles bind the original template 2,4-D with an appreciable selectivity over structurally related compounds. The potential use of the surface-imprinted core—shell nanoparticles as the recognition element in the competitive fluorescent binding assay for 2,4-D was also demonstrated. [ABSTRACT FROM AUTHOR]