Novel Synthesis of Thiolated Gold Nanoclusters Induced by Lanthanides for Ultrasensitive and Luminescent Detection of the Potential Anthrax Spores’ Biomarker
Mohamed Ibrahim Halawa, Bing Shi Li, Guobao Xu
Abstract
In this study, we reported a facile, one-pot, and “green” synthesis of glutathione-protected gold nanoclusters (GSH@AuNCs) initiated by samarium (Sm3+) lanthanides for the first time. Sm3+ lanthanides more efficiently induced the formation of GSH@AuNCs with significantly enhanced luminescence than other lanthanides or heavy metal ions (Cd2+, Pb2+) did. Using this strategy, a detection for Sm3+ was made with a linearity range of (10.0–100.0 μM) and a limit of detection (LOD) of 0.5 μM. The Sm3+-based GSH@AuNCs were characterized by eco-friendliness, photostability, and low-cost synthesis with low biological toxicity and had great potential in the application for biosensing and bioimaging. They were successfully employed in the detection of dipicolinic acid (DPA), a well-reported biomarker for sensing potential infection by strongly hazardous anthrax spores. A good linear response was obtained for DPA detection ranging from 1.0 to 120.0 μM with a low LOD of 0.1 μM, which was much lower (600 times) than the infectious dosage of anthrax spores (6 × 10–5 M). The detection was due to the strong binding affinity and strong chelation capability of DPA to Sm3+ lanthanides, which caused the dissociation of the aggregates with an obvious decrease or even a turning-off effect of their luminescence.