An electrochemical aptasensor based on graphene doped chitosan nanocomposites for determination of Ochratoxin A

A simple and efficient functionalized graphene (f-graphene) doped chitosan (CS) based electrochemical aptasensor has been developed for ochratoxin A (OTA) detection. Use of f-graphene increased the electroactive surface area of the electrode and CS prevented leaching of the aptamer (APT) molecules. The dual properties of CS and f-graphene overall improved the sensor performance. The developed APT/SA/CS-f-graphene sensor has been characterized using Fourier Transform Infrared Spectroscopy (FTIR), Contact angle, Field emission - scanning electron microscopy (FE-SEM) and electrochemical studies. The aptasensor displayed OTA limit of detection (LOD) about 1 fg/mL for standard and 0.01 ng/mL for spiked sample within response time of 8 min. The reusable aptaelectrode retained 85% of initial current values after 7th reaction with stability of about 7 days. Besides, real application of the fabricated aptasensor has been evaluated in the grape juice samples. Recoveries of OTA in the range of 90-101% were estimated successfully.