A highly selective and sensitive fluorescent probe for lactate dehydrogenase based on ultrabright adenosine monophosphate capped gold nanoclusters

Ultrabright adenosine monophosphate (AMP) capped gold nanoclusters (AuNCs@AMP) were used as a novel fluorescent probe to detect lactate dehydrogenase (LDH), an important biomarker of common injuries and diseases. The fluorescence emission of AuNCs@AMP is quenched linearly in the presence of a wide concentration range of LDH (50-1000 nM), covering the range for clinical diagnosis. Particularly, the detection is very sensitive with an extremely low detection limit of 0.2 nM (26 pg mu L-1, 0.8 U L-1), being more sensitive than the previously reported ones. However, the proposed probe does not response to other commercially available proteins with different isoelectric points, which shows a high selectivity toward LDH. In addition, the response mechanism is also investigated in detail, where the quenching response is attributed to the binding of AuNCs to the free thiol groups at the LDH surface. Therefore, the present study supplies a cost-effective, fast and easily performed approach to detect LDH with high selectivity and sensitivity, which has potential use in clinical diagnosis in future.