BODIPY functionalized Au nanoparticles (PyBDP-AuNPs) have been developed for detecting cysteine. Gold nanoparticles were prepared by reducing HAuCl4 with sodium citrate, using PyBDP as the capping agent. Upon addition of cysteine, PyBDP molecules are liberated from the AuNP surface through ligand-exchange displacement based on the strong affinity of Au with the thiol group and result in green fluorescence from PyBDP molecules. This cysteine-induced displacement of PyBDP-AuNPs was monitored by fluorescent spectroscopy with a detection limit of 1.2 μM. Optimal detection of cysteine was achieved over a pH range from 5 to 12. In addition, PyBDP-AuNPs can be used as a fluorescent probe for detecting cysteine in living cells.
- Gold nanoparticles
- Imaging agents