On-demand controlled bidirectional DNAzyme path for ultra-sensitive heavy metal ion detection.

A bidirectional self-powered biosensor is constructed for the quasi-simultaneous detection of Pb and Hg based on MoS@CuS heterostructures as an accelerator and hybridization chain reaction (HCR) as a signal amplification strategy. MoS@CuS heterostructures significantly facilitate electron transfer between glucose and bioelectrodes, thereby greatly improving the detection signal of self-powered biosensors. This novel biosensor employs the unique sequences of DNAzymes to isolate Pb and Hg by the cleavage effect and thymine (T)-Hg-thymine (T) structures, respectively.