Magnetic organoiridium nanocatalysts activate fluorescence biosensors

Here, we developed the cyclodextrin-organoiridium-functionalized magnetic nanocatalyst MBs@CD@Ir by assembling highly active adamantane-functionalized pyridinamide organoiridium complexes PicPh-Ada-Ir and cyclodextrin-modified magnetic nanoparticles MBs@CD , which could efficiently catalyze quinone hydrogenation using the cofactor NADH as a hydrogen source under physiological conditions. Furthermore, by combining the developed catalysts MBs@CD@Ir and the quinone hydrogenation-triggered Rhodamine 110-type fluorescence probe Q-Rho 110 , we successfully established a sensitive cofactor NADH fluorescence sensor, which showed superior hydrogenation performance for quinone when NADH was used as a hydrogen source. The established sensor presented excellent detection performance for NADH with a limit of detection (LOD) of 4.18 nM and was successfully applied to NADH detection in Escherichia coli fermentation broth. The established sensor has successfully expanded the application of organometallic catalysts in biosensing and provides a new approach for the design of other sensors.