DNAzyme-manipulated fluorescence signal variation of DNA-AgNCs and construction of an aptasensor for ATP

Abstract

DNA-templated silver nanoclusters (DNA-AgNCs) are novel nanomaterials with unique fluorescence characteristics. DNAzyme is a functional oligonucleotide which can catalyze the disruption of nucleic acid substrates. In this research, the manipulation of DNAzyme digestion on the fluorescence property of DNA-AgNCs was explored for the first time. A significant reduction in fluorescence intensity of DNA-AgNCs after cleavage by DNAzyme was discovered. Further research found that the DNAzyme-catalyzed cleavage reduces the stability of DNA-AgNCs and leads to the aggregation of DNA-AgNCs, accounting for a decline in fluorescence intensity up to 84%. Inspired by the above finding, a fluorescent aptasensor that integrates the benefits of DNA-AgNCs, exonuclease III (Exo III)-assisted signal amplification and DNAzyme was developed for sensitive detection of adenosine triphosphate (ATP). Under the optimal conditions, the linear range runs from 25 μM to 1000 μM, and the detection limit is estimated to be 4.46 μM. Furthermore, this fluorescent aptasensor has been effectively employed to quantify ATP level in human serum samples, demonstrating its practicality in detecting ATP in biological matrices. The elucidation of DNAzyme-manipulated fluorescence characteristic variation of DNA-AgNCs may provide insights into the interactions between DNAzyme and nanomaterials and have great prospects in the construction of fluorescent biosensors.