An Autocatalytic DNA Circuit Based on Hybridization Chain Assembly for Intracellular Imaging of Polynucleotide Kinase.

Polynucleotide kinase (PNK) plays an essential role in various cellular events by regulating phosphorylation processes, and abnormal homeostasis of PNK could cause many human diseases. Herein, we proposed an autocatalytic hybridization system (AHS) through the elaborate integration of hybridization chain assembly (HCA) and catalytic DNA assembly (CDA) that enables a highly efficient positive feedback amplification. The PNK-targeting AHS biosensor is composed of three modules: a recognition module, an HCA amplification module, and a CDA autocatalytic module. In the presence of PNK, the recognition module could transform the PNK input into an exposed nucleic acid initiator (