Gold Nanoclusters/Iron Oxyhydroxide Platform for Ultrasensitive Detection of Butyrylcholinesterase

The combination of gold nanoclusters (AuNCs) and nanomaterial-based quencher creates an innovative method for sensors design. In this work, we report a fluorescent sensing platform for sensitive detection of butyrylcholinesterase (BChE). The fluorescence of AuNCs can be quenched by iron oxyhydroxide (FeOOH) nanomaterials. In the presence of BChE and acetylthiocholine (ATCh), nano-FeOOH can be effectively decomposed by the enzymatic hydrolysate (thiocholine), leading to the recovery of AuNCs fluorescence. The Au/FeOOH exhibits the highest fluorescence quenching efficiency compared with other transition metal oxyhydroxide-based sensing systems, e.g., Au/CoOOH and Au/NiOOH. The corresponding fluorescence recovery efficiency is also the best for Au/FeOOH. The large surface area of nanomaterials and thin nanostructure provide a favorable platform for the reaction of enzymatic hydrolysate and eventually improve the high sensitivity of the probe. A linear detection range for BChE is achieved within 5-100 ng mL^-1 along with a detection limit of 4 ng mL^-1. By taking advantage of the high sensitivity, the Au/FeOOH was successfully used for BChE quantification in 2 μL of finger blood.