A sensitive electrochemiluminescence immunoassay for glycosylated hemoglobin based on Ru(bpy)32+ encapsulated mesoporous polydopamine nanoparticles

Abstract

A sensitive electrochemiluminescence (ECL) immunosensor was successfully fabricated utilizing Ru(bpy)32+-doped mesoporous polydopamine (MPDA) for subtle exploration of the diabetes biomarker glycosylated hemoglobin (HbA1c). In this protocol, with the advantages of relatively large specific surface area and good biocompatibility, MPDA nanoparticles are capable of loading more Ru(bpy)32+ to greatly amplify the ECL efficiency during the existence of trinpropylamine (TPA) as common coreactant. The acquired Ru(bpy)32+@MPDA nanoparticles are used as a beneficial substrate for immobilizing aptamer, thereby specifically recognizing the targeting substance HbA1c as much as possible with high selectivity. It could be noted from the experimental results that the ECL intensity was evidently reduced as the proposed Ru(bpy)32+@MPDA ECL immunosensor captured HbA1c, which showed the principle of the ECL quenching determination. Under optimal experimental conditions, the prepared Ru(bpy)32+@MPDA ECL immunosensor exhibited wide linear range from 0.1% to 18.5% with the low detection limit (LOD) of 0.015% (S/N = 3) and the correlation coefficient (R2) of 0.994. Moreover, the Ru(bpy)32+@MPDA immunosensor displayed high sensitivity and selectivity for detecting HbA1c. Therefore, the as-obtained Ru(bpy)32+@MPDA ECL immunosensor will open up a new promising platform for highly sensitive bioassay of HbA1c.