Development of molecularly imprinted photonic polymers for sensing of sulfonamides in egg white

Abstract

We developed a simple method based on molecularly imprinted photonic polymers (MIPPs) for sensing of sulfonamides in egg white samples. The fabrication of MIPPs mainly involved a photonic crystal template method integrated with a molecular imprinting technique. Firstly, an opal photonic crystal template was self-assembled from monodisperse polystyrene colloids. And then the template was embedded with molecularly imprinted polymers, which was synthesized with acrylic acid and acrylamide as monomers, N,N′-methylenebisacrylamide as a cross-linker and sulfamerazine (SM1) or sulfamethazine (SM2) as imprinting molecules. After removal of the photonic crystal template and the imprinted molecules, the resultant MIPP sensor accommodated an inverse opal photonic crystal structure embedded in hydrogels. By using the as-prepared MIPP sensor, sulfonamides were sensitively and specifically recognized via a molecular imprinting technique and the recognition was detected through the readable Bragg diffraction shift from the photonic crystal structure. A 70 nm maximum Bragg diffraction blue-shift of the MIPP was observed with the concentrations of the sulfamerazine or sulfamethazine varying from 3.8 μM to 22.8 μM and function relationships were found between blue-shifts and the concentrations of sulfonamides in pH 5 acetic acid–sodium acetate buffer solution. The developed method has been applied successfully to detect sulfonamides in egg white samples without using labelling techniques and expensive instruments.