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

• Published in: Microchemical journal 2019-01, Vol.144, p.102-109
• Main Authors: Kaur, Navpreet, Bharti, Anu, Batra, Supriya, Rana, Shilpa, Rana, Shweta, Bhalla, Aman, Prabhakar, Nirmal
• Format: Article
• Language: English
• Subjects: Aptamers; Chitosan; Electrochemical aptasensor; F-graphene; Food sample; Ochratoxin A
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2018.08.064

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. •Chitosan (CS) and graphene (f-graphene) has been used as suitable matrix for immobilization of aptamer (APT)•Biotinylated APT was immobilized onto streptavidine (SA) attached f-graphene via streptavidine-biotin coupling.•Detection limit of Ochratoxin A (OTA) is 1 fg/mL. Recoveries of OTA from the spiked grape juice ranged between 90-101%.•Reusability and shelf life was observed to be 7 times and 7 days, respectively.