Multi-quenching electrochemiluminescence system based on resonance energy transfer from self-enhanced Ce(III, IV)-MOF@Ru to CuO@PDA@AuNPs for ultrasensitive detection of HER2

This study presents an innovative approach based on electrochemiluminescence resonance energy transfer (ECL-RET) through the introduction of a new pattern donor-acceptor couple. The donor of self-enhanced Ce(III, IV)-MOF@Ru is created by immobilizing Ru(bpy)₃²⁺ on Ce-based metal-organic frameworks (Ce(III, IV)-MOF). The acceptor of CuO@PDA@AuNPs is the CuO nanospheres polydopamine (PDA) framework grafted with gold nanoparticles (AuNPs). An ultrasensitive detection of human epidermal growth factor receptor-2 (HER2) was achieved through the development of a quenched ECL immunosensor. Ce(III, IV)-MOF, a unique 3D infinite extension framework, was recognized for its excellent nanostructure and remarkable capacity to greatly activate tripropylamine (TPrA) and generate abundant radicals. Fortunately, it was simultaneously utilized as a highly effective coreactant accelerator and encapsulation agent, thereby facilitating the immobilization of Ru(bpy)₃²⁺ and the generation of radicals for creating a self-enhanced emitter of Ce(III, IV)-MOF@Ru. Consequently, by effectively reducing the distance of electron transmission and minimizing the loss of energy, Ce(III, IV)-MOF@Ru achieved a significantly high efficiency in ECL. More importantly, CuO@PDA@AuNPs was prepared as a perfect quenching agent. The ultraviolet-visible (UV-vis) spectra of CuO@PDA@AuNPs exhibited partial overlap with ECL spectra of Ce(III, IV)-MOF@Ru, thus efficiently initiating the ECL-RET interaction between the donor and acceptor. With the purpose of demonstrating the superiority of newly obtained self-enhanced nanoemitter and donor-acceptor couple, an ECL immunoassay was proposed for the analysis of HER2 with range of 0.2 fg/mL ~ 10 ng/mL and the limit of detection of 0.067 fg/mL. Therefore, this method supplies convenient and significant strategy for the clinical analysis.