Structural Characterization and Biocompatible Applications of Graphene Nanosheets for Miniaturization of Potentiometric Cholesterol Biosensor
- *Corresponding Author:
- Dr. M. Q. Israr
Department of Science and Technology
Linköping University,SE-60174 Norrköping
E-mail: [email protected]
Received Date: October 25, 2011; Accepted Date: November 09, 2011; Published Date: November 19, 2011
Citation: Israr MQ, Hasan Ku, Sadaf JR, Engquist I, Nur O, et al. (2011) Structural Characterization and Biocompatible Applications of Graphene Nanosheets for Miniaturization of Potentiometric Cholesterol Biosensor. J Biosens Bioelectron 2:109. doi: 10.4172/2155-6210.1000109
Copyright: © 2011 Israr MQ, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The potentiometric cholesterol biosensor based on graphene nanosheets has been successfully miniaturized. Homogeneous exfoliation of the mono- and double-layered graphene nanosheets on copper wire is achieved by drop casting the graphene nanosheets suspended in N-methyl-pyrrolidone solution. The process of physical adsorption has been utilized to immobilize the cholesterol oxidase onto graphene nanosheets. Morphological, crosssectional and structural crystallinity of the nanosheets have been investigated using atomic force microscope and transmission electron microscope. Ultraviolet-visible absorption and Fourier transform infrared spectrometers have been used to confirm the presence of the graphene nanosheets and their conjugation with cholesterol oxidase. The presented potentiometric biosensor renders effective selectivity and sensitivity (~82 mV/decade) for the detection of cholesterol biomolecules in 1 × 10−6 M to 1 × 10−3 M logarithmic range and quick output response within ~ 4 sec. The stability and reusability of the biosensor have also been investigated for the above mentioned range of cholesterol concentrations. Additionally, the functioning of presented biosensor is studied for the ranges of the temperature of 15-70 °C and pH values (4-9).