An autonomous driven DNA walker-based electrochemical aptasensor for on-site detection of Ochratoxin A

Herein, an autonomous driven DNA walker-based aptasensor is proposed for the detection of Ochratoxin A (OTA). A nanoscale metal-organic framework (MOF) is synthesized and used to load Mn²⁺, a cofactor for DNAzyme. The DNA walker and Mn²⁺@MOF are assembled on the Au surface, integrating the DNA walker and metal auxiliary ions. The proposed sensor avoids the addition of metal auxiliary ions of DNAzyme from the external environment, which achieves the fully autonomous driving of DNA walker and facilitates the on-site detection of OTA. In addition, the substrate strands are modified with a newly synthesized tetraferrocene signal marker, further achieving signal amplification. The sensor demonstrates a sensitivity of 0.289 pg/mL and is successfully applied to real food sample analysis.