Fluorometric determination of the activity of the biomarker terminal deoxynucleotidyl transferase via the enhancement of the fluorescence of silver nanoclusters by in-situ grown DNA tails

The activity of terminal deoxynucleotidyl transferase (TdTase) is a biomarker for routine diagnosis of acute leukemia. A method has been developed for the determination of TdTase activity. It is based on the use of silver nanoclusters (AgNCs) whose yellow fluorescence is enhanced by an in-situ grown DNA tail of TdTase-polymerized and guanine-rich DNA at the 3 end of a hairpin DNA. The fluorescence, best measured at excitation/emission peaks of 530/585nm, increases linearly in the 1 to 35mUmL(-1) TdTase activity range. The detection limit is 0.8mUmL(-1). The method is cost-efficient, selective and convenient. It integrates enhancement of the fluorescence of AgNCs and target recognition into a single process.