An electrochemiluminescence sensor of magnetic glycosyl-imprinted microspheres based on multi-probe signal amplification for CD44v6 determination

Abstract

A CD44v6 detection method was developed by using glycosyl-imprinted technique and enhanced with multi-probe signal amplification. Oligomeric hyaluronic acid was used as the template molecule, which was prepared by the cleavage of polyhyaluronic acid using hyaluronidase. Mercaptophenylboronic acid was self-assembled on the surface of core-shell [email protected]3O4 magnetic microspheres through the covalent interaction between its thio group and Au. Then oligomeric hyaluronic acid (<10 kDa) was linked on [email protected]3O4 via the formation of a cyclic ester between boronic acid and the ortho-dihydroxy group of oligomeric hyaluronic acid. By using oligomeric hyaluronic acid as a template and p-aminophenylboronic acid (p-APBA) as the functional monomer, boronate affinity glycosyl-imprinted polymer films were prepared on [email protected]3O4 by chemical polymerization. The magnetic glycosyl-imprinted polymer microspheres (MGIP) were attached on the surface of the magnetron-controlled glassy carbon electrode (MGCE) as the recognition component rebinding for the template, and CD44v6 was specifically recognized by the binding of the imprinted cavities to the oligomeric hyaluronic acid. The boronic acid functionalized tris-(2,2’-bipyridyl) ruthenium (II) (Ru(bpy)3-BO3) was used as a molecular probe to label the adsorbed oligomeric hyaluronic acid of CD44v6. With the aid of the multiply captured Ru(bpy)32+ probes on CD44v6 and the high luminescence efficiency of Ru(bpy)32+, the electrochemiluminescence response of the sensor exhibits a high sensitivity for CD44v6 determination with a detection limit of 0.08 ng/L. The method was applied in the assay of CD44v6 in serum samples.