Electron Accelerator-Enhanced Au Nanoclusters Electrochemiluminescence for Ultrasensitive Detection of Low-Expression Protein Based on DNA Hybridization Correctional Immunoreaction

Herein, a novel electrochemiluminescence (ECL) sensing platform was constructed by the DNA hybridization correctional immunoreaction as the target recognition element and ZnO nanostars (ZnO NSs) as an electron accelerator for Au nanoclusters (Au NCs) emitters for ultrasensitive and specific detection of the low expression of glial fibrillary acidic protein (GFAP) related to glioblastoma. Compared with traditional sandwich immunoreactions with low accuracy, the DNA hybridization correctional immunoreaction not only achieved high specificity of target recognition by the cross-correction between the conformational correspondence of the antibody–antigen and the spatial position of strand DNAs but also enhanced the target recognition efficiency by the modulation of thermodynamic stability via adjustment of the DNA stem length. Impressively, ZnO NSs as an electron accelerator could rapidly transfer the electrons of emitter Au NCs to the vacancy defects of ZnO NSs during electroexcitation, generating more excited-state Au NCs for strong ECL emission. The ECL efficiency of Au NCs@ZnO NSs (12.89%) was significantly higher than that of pure Au NCs (2.69%) versus standard [Ru(bpy)3]2+. As a result, the sensing platform achieved trace analysis of GFAP with a detection limit as low as 60 fg/mL, surpassing existing ECL biosensors for protein detection. Meanwhile, it displayed a higher positive/negative predictive value and a lower false positive/negative rate compared to those of the traditional sandwich immunoassay method. This strategy proposed a new electron accelerator-enhanced ECL emission of metal NCs for ultrasensitive protein detection through DNA hybridization correctional immunoreaction, displaying promising potential for applications in clinical diagnostics.