A dual-mode biosensor based on CdIn2S4 hollow microsphere combined with Au@CuO/Cu2O nanozyme for sensitive detection of Sa-16S rDNA

A dual-mode biosensor used CdIn2S4 hollow microspheres as electrochemiluminescence (ECL) and photoelectrochemistry (PEC) dual signal probes combined with Au@CuO/Cu2O nano-enzyme catalysis was fabricated for sensitive detection of Sa-16S rDNA. Firstly, CdIn2S4 microspheres displayed excellent ECL and PEC signals, then the target Sa-16S rDNA introduced a large number of Au@CuO/Cu2O nanoparticles to the electrode via Exo-III amplification strategy. Au@CuO/Cu2O is a highly efficient peroxidase mimicase, and can effectively promote H2O2 to produce ·OH, which further oxidized 4-chloro-1-naphthol (4-CN) to produce a large amount of insoluble precipitate on the electrode surface, then significantly reduced the PEC and ECL signals of CdIn2S4 for target detection. This study opens up a new multifunctional photoelectric microspheres and a flexible biosensor by using CdIn2S4 and nanozymes, showing a new channel for the detection of DNA molecules and providing valuable insights for the development of PEC biosensing technologies based on nanozymes.