A cucurbit[7]uril/gold nanoparticle self-assembly mediated chemiluminescence resonance energy transfer immunoassay for insulin detection.

Abstract

As insulin is the core regulatory hormone maintaining blood glucose stability, its abnormal secretion is often associated with diseases such as diabetes. In order to break away from the dependence on the traditional insulin detection technology involving expensive instruments and complex operations, we present a cucurbit[7]uril (CB[7])/gold nanoparticle (AuNP) self-assembly mediated chemiluminescence resonance energy transfer immunoassay (CRETIA) for insulin detection. The AuNP@CB[7] self-assembly serves two critical roles: the biorecognition element for capturing insulin from complex samples via host-guest interaction and the catalyst for the chemiluminescent reaction due to the enzyme-like activity of AuNPs. Upon introducing the energy acceptor antibody (Ab)-graphene oxide (GO) nanosheets, the presence of insulin leads to the formation of AuNP@CB[7]/insulin/Ab-GO nanosheet complexes, in which the AuNP and GO nanosheets are in close proximity, resulting in significant quenching of the chemiluminescence signal. Under optimized conditions, a satisfactory linear relationship was obtained in the range of 10-5000 pg mL^-1, with a limit of detection (LOD) of 2.51 pg mL^-1. The proposed CRETIA involves no use of natural enzyme or tedious washing and separation steps, thereby providing a robust tool for rapid detection of insulin.