Protein-building molecular recognition sites by layer-by-layer molecular imprinting on colloidal particles

Abstract

In this paper, we report a layer-by-layer (LbL) molecular imprinting strategy for constructing molecular recognition sites at the surface of colloidal silica particles by glutaraldehyde (GA)-mediated covalent assembly of gelatin protein in aqueous media. Accompanying the repeated coating of gelatin at the amine-capped silica particles, 2,4,6-trinitrotoluene (TNT) templates were synchronously imprinted into the formed gelatin shells by the charge-transfer interaction between the electron-deficient aromatic rings of TNT and the electron-rich amino groups of gelatin chains. The effective molecular recognition sites generated at the protein interlayers of gelatin shells of monodisperse silica@gelatin particles, and the rebinding TNT capacities changed nonlinearly with the layer number of imprinted gelatin. Three layers of imprinted gelatin produced the largest imprinting factor of ∼3.0, which is explained by the covalent assembly mechanism. The imprinting protocol is applicable to a broad range of biomaterials (such as proteins, enzymes, chitosan and biopolymers) for imprinting various molecules in aqueous media. Therefore, these results reported here will open a new window of interest in the exploration of novel molecular recognition systems for application in chemosensors, selective separation, and drug screening and release.