AuNPs-DNAzyme motor triggered two colors DNA tweezer for fluorescent amplified detection of bisphenol A.

An AuNPs-DNAzyme motor triggered ultrasensitive, two colors DNA tweezer was developed for fluorescent detection of bisphenol A (BPA). BPA can bind with its aptamer on the gold nanoparticles (AuNPs) and reactivate the Pb2+ enzyme strands. Thus, Pb2+ enzyme strands can cleave the substrate strand on AuNPs and release a DNA fragment from AuNPs. The released DNA fragment can bind with the loop of the Y shaped DNA tweezer to form Mg2+-specific DNAzyme, the following cleavage causing the leaving of another two DNA fragments. Then, these two DNA fragments can open the two ends of the Y shaped DNA tweezer, causing the recovery of fluorescent signals. This strategy shows a good linear relationship for BPA detection from 0.44 to 2.2 × 103 pM. The sensitivity has been significantly improved by the two levels of amplification strategy DNAzyme motor and cyclic cleavage of the loop. Importantly, it also can significantly reduce the false positive result by two colors signals. Moreover, it also exhibits satisfactory performance in practical sample detection.