An electrochemiluminescence biosensor based on morphology controlled iridium complex nanomaterials for SARS-CoV-2 nucleocapsid protein detection

Abstract

The morphology of electrochemiluminescence (ECL) emitters is closely related to ECL properties, thus the control of their morphology is greatly essential for ECL applications. Herein, a facile nanoprecipitation method was developed to realize controllable morphology of iridium complex nanomaterials by modulating the volume ratio of poly(styrene-co-maleicanhydride) (PSMA) to tris (2-phenylpyridine) iridium(Ⅲ) (Ir(ppy)3). Furthermore, ECL properties of iridium complex nanomaterials with different morphologies were explored through a series of experiments. Iridium complex nanoparticles (Ir NPs) with excellent ECL performance were selected as admirable ECL emitters to construct biosensors. Ir NPs served as the matrix to stepwise capture primary antibody, antigen of SARS-CoV-2 nucleocapsid protein (ncovNP) and secondary antibody bioconjugate coupled with dual quenchers and detection antibody. Taking advantage of the significant quenching effect of noradrenaline (NA) and gold nanoparticles (Au NPs) in the secondary antibody bioconjugate on ECL emission from Ir NPs, the developed ECL biosensor realized the sensitive detection of ncovNP and the detection limit was as low as 47 fg/mL. The integration of morphology-controlled iridium complex nanomaterials and dual quenchers NA and Au NPs provides a promising ECL platform.