AN ELECTROCHEMILUMINESCENCE SANDWICH BIOSENSOR FOR THE DETECTION OF LIPOPOLYSACCHARIDE

A novel electrochemiluminescence (ECL) biosensor for the determination of lipopolysaccharide (LPS), a biomarker of endotoxemia, was designed. The nanoprobe (Ru1@SiO2-peptide) with a specific peptide (CIGKLHSAGK) labeled with a carboxyl functionalized Ru@SiO2 (Ru1@SiO2) was prepared by the acylation reaction. The ECL peptide biosensor was obtained by the strong gold-sulfur bond between Au on the gold electrode (AuE) surface and thiol group in the peptide. In the present of LPS, the peptide on the ECL biosensor can capture effectively LPS and the LPS/peptide/AuE was fabricated. When the Ru1@SiO2-peptide nanoprobe was bound, a sandwich compound of Ru1@SiO2-peptide/LPS/peptide was formed, and Ru(bpy)32+, in the sandwich compound, will do the ECL performance. The effective ECL amplification of Ru1@SiO2 exhibited excellent analytical performance to LPS with a wide detection linear range of 1.0~500 ng mL-1 and the detection limit was 0.3 ng mL-1. The biosensor could provide an evaluate of LPS expression on the bacteria surface and guide a new path to the clinical analysis of LPS related diseases.