Ultrasensitive electrochemiluminescence determination of Salmonella based on CRISPR/Cas12a integrated with bimetallic semiconductive metal-organic frameworks
摘要
An ultrasensitive electrochemiluminescence (ECL) biosensor was established by combining CRISPR/Cas12a technique and semiconductive bimetallic-organic framework (scMOF) [[CuxNi3−x(HITP)2] (HITP = 2,3,6,7,10,11-hexaiminotriphenylene)]] emitter and employed to detect Salmonella using the allosteric probe as the recognition component. Given that CuxNi3−x(HITP)2 has demonstrated large specific surface area, both in-plane and out-of-plane charge transfer ability, narrowed band gap, and enhanced separation of holes and electrons, it can be simultaneously employed as the superior ECL emitter and bioplatform for anchoring single-strand DNA (ssDNA), thus improving the detection sensitivity toward Salmonella. The CRISPR/Cas12a-based system can specifically recognize the target sequence of Salmonella and activate the nuclease activity of Cas12a, and the activated Cas12a possesses trans-cleavage ability toward ssDNA. The CuxNi3−x(HITP)2 emitter is then released, resulting in the decline of the ECL response. The developed CuxNi3−x(HITP)2-CRISPR/Cas12a-based ECL biosensor exhibits the ultralow detection limit of 0.25 CFU mL− 1 in the linear range from 1.0 CFU mL− 1 to 106 CFU mL− 1, significantly lower than those of reported ones. Furthermore, the developed biosensor exhibits outstanding overall biosensing properties with high selectivity, favorable reproducibility and stability, together with promising practical applicability for the determination of Salmonella in a variety of foodstuffs.
Graphical Abstract