High-Sensitive Impedimetric Aptasensor for Detection Ochratoxin A in Food

摘要

We report a high sensitive biosensor based on DNA aptamers for detection ochratoxin A (OTA). The thiolated DNA aptamers specific to OTA have been immobilized to a surface of gold electrode. The electrochemical impedance spec-troscopy (EIS) at presence of redox probe [Fe(CN)_6]~(-3/-4) has been used for determination of charge transfer resistance, R_(ct), following addition of OTA. We have shown that R_(ct) increased with increasing OTA in a range of 0.1-100 nM. The sensor revealed high sensitivity (the limit of detection was 0.44 nM), selectivity and was regenerable. The sensor was validated in coffee extract.