Graphene oxide-chitosan nanocomposite based electrochemical DNA biosensor for detection of typhoid

• Published in: Sensors and actuators. B, Chemical Vol. 185; pp. 675 - 684
• Main Authors: Singh, Anu, Sinsinbar, Gaurav, Choudhary, Meenakshi, Kumar, Veeresh, Pasricha, Renu, Verma, H.N., Singh, Surinder P., Arora, Kavita
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2013
• Subjects: base pair mismatch; biocompatibility; biosensors; blood serum; Chitosan; DNA; electrochemistry; electrodes; electron transfer; glutaraldehyde; graphene; Graphene oxide; hybridization; Nano composite; nanocomposites; Salmonella; Salmonella Typhi; Typhoid; typhoid fever; Salmonella; Graphene oxide; Chitosan; Typhoid; Nano composite; DNA
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2013.05.014

Graphene oxide (GO)-Chitosan (CHI) nano-composite is employed for the development of DNA based electrochemical biosensor for diagnosis of typhoid. Biosensor has been prepared by covalent immobilization of Salmonella typhi specific 5′-amine labeled single stranded (ss) DNA probe on GO-CHI/ITO via glutaraldehyde. Differential pulse voltammetry (DPV) studies revealed good specificity and ability of ssDNA/GO-CHI/ITO biosensor to distinguish complementary, non-complementary and one base mismatch sequences. The ssDNA/GO-CHI/ITO biosensor showed detection range of 10fM to 50nM and LOD 10fM within 60s hybridization times for complementary sequence. Further, ssDNA/GO-CHI/ITO bioelectrode is able to detect complementary target present in serum samples with LOD of 100fM at 25°C. The excellent performance of biosensor is attributed to large surface-to-volume ratio and good electrochemical activity of graphene oxide, and good biocompatibility of chitosan, which enhances the DNA immobilization and facilitate electron transfer between DNA and electrode surface (ITO).