Cu nanoclusters/nano-vesicle-based confinement-induced electrochemiluminescence strategy for miRNA-145 detection

A novel confinement-induced ECL enhancement (CIECL) sensing system has been constructed based on copper clusters (Cu NCs) and nano-vesicles in this work. The CIECL strategy resolved the shortcoming of poor stability and low luminous intensity of Cu NCs. Firstly, nano-vesicles were prepared through liquid-liquid self-assembly with amyl gemini quaternary ammonium salt and anionic surfactant. Subsequently, Cu NCs were confined in the nano-vesicles by electrostatic interaction. Due to the restriction on the intramolecular vibration and rotation of the ligands of Cu NCs, the Cu NC/nano-vesicle-based CIECL system showed the significant luminescence enhancement, good stability and high biocompatibility. Additionally, the Au nanoparticles-array with significant surface plasmon resonance effect has been prepared to further amplify the ECL intensity. Finally, the CIECL-based biosensor has been successfully used to detect miRNA-145 in clinic samples in the linear range of 100 fM to 100   nM, which displayed the potential value in the vascular calcification analysis.