Molecularly-Imprinted Calcium Phosphate/Calcium Alginate Composite Microspheres by Surface Imprinting via Silane Crosslinking

Abstract

This paper describes the development of a new type of molecularly-imprinted composite microspheres. Composite microspheres of calcium phosphate/calcium alginate (CP/CA CMs) were prepared from calcium phosphate and sodium alginate through the use of calcium chloride (CaCl 2 ) as a gelling agent in an inverse suspension. Molecularly-imprinted calcium phosphate/calcium alginate composite microspheres (CP/CA MICMs) were then prepared by surface imprinting using CP/CA CMs as the supporting matrix, ethylene tri(β-methoxy)ethoxysilane (A-172) and γ-amidopropyltriethoxysilane (KH-550) as the functional monomers and crosslinking agents, respectively, and Methyl Orange as the template in aqueous solution. The CP/CA MICMs and non-imprinted composite microspheres (NICMs) were characterized by Fourier-transform infrared spectroscopy and optical microscopy. The adsorption behaviour of the CP/CA MICMs and NICMs were determined by ultraviolet spectrophotometry. The results indicated that molecular imprinting occurs via the crosslinking of silanes on the surface of the CP/CA CMs, and that CP/CA MICMs possess an adsorption capacity which exhibits greater selectivity. A schematic representation of the imprinting and recognition process of CA/CP MICMs by surface imprinting via silane crosslinking was presented.