Bimetallic gold/silver nanoclusters as a fluorescent probe for detection of methotrexate and doxorubicin in serum

摘要

New bimetallic gold/silver nanoclusters (NCs) are reported that display strong blue fluorescence with excitation/emission maxima at 370/455nm, decay times of around 14ns for the main components, and a quantum yield of around 20%. The NCs were synthesized by using L-tryptophan (L-Trp) as the template to react with tetrachloroauric acid and silver nitrate at 120 degrees C for 4h in a one-pot reaction. Their fluorescence is around 5 times stronger than that of pure gold nanoclusters. The fluorescence of the bimetallic NCs is strongly reduced in the presence of the antitumor drugs methotrexate (MTX) and doxorubicin (DOX) due to an inner filter effect. Response to MTX is linear in the 2.5-150M concentration range, and to DOX in the 2.5-150M concentration range. The detection limits are as low as 2.5nM and 3nM, respectively. The recoveries from spiked serum are between 87.7% - 101.2% for MTX and between 86.2%-105.4% for DOX.