Flower-like metal-organic framework microsphere as a novel enhanced ECL luminophore to construct the coreactant-free biosensor for ultrasensitive detection of breast cancer 1 gene

•High-efficiency ZnMOF(Ru) was obtained via a simple solvothermal method.•The unique ZnMOF(Ru) increased the mass loading and utilization efficiency of Ru(dcbpy)32+ effectively.•ZnMOF(Ru)-based coreactant-free ECL biosensor was fabricated for ultrasensitive detection of BRCA1. Nowadays, serious restriction by aggregation quenching and proton attack in aqueous media, electrochemiluminescence (ECL) signals of emitter hardly match the requirement of ultrasensitive biomedical detection in practice. In this work, a novel flower-like metal-organic framework microsphere was formed by chelating Zn ion with carboxyl-rich tris(4,4′-dicarboxylic acid-2,2′-bipyridyl) ruthenium(II) (Ru(dcbpy)32+) in the presence of cetyltrimethylammonium bromide (CTAB), defined as ZnMOF(Ru) for simplicity. For that, the obtained ZnMOF(Ru) as a high-performance ECL emitter displayed 53-fold amplification in aqueous solution without any coreactant alternative to that of Ru(dcbpy)32+, coupled with the dramatically enhanced fluorescence quantum yield and stability of the intermediates. Thus, a “sandwich”-like ECL biosensor was developed for detecting breast cancer 1 gene (BRCA1), showing the wide linear range (1.0 fM–0.1 nM) and ultralow limit of detection (LOD) down to 0.71 fM. Hence, this work provides a universal and robust pattern to develop advanced ECL luminophores and exploit their potential applications in bioanalysis.