Biosensing is a crucial part of human well-being as early detection of diseases requires highly sensitive and selective methods. Different types of biosensors are thus being developed for more accurate and faster analysis in mind. New materials, such as graphene oxide, are evaluated for improved biosensor performance.
Biomolecules can be immobilized to graphene oxide
Graphene oxide (GO) is the oxidized form of graphene. It is a single-atomic-layered material that is formed by the oxidation of graphite which is cheap and readily available. Graphene oxide is easy to process since it is dispersible in water and other solvents. For biosensing applications, it can be easily complexed with biomolecules as graphene oxide is covered with different functionalities such as epoxy, hydroxyl and carboxylic groups. The functionalization of GO also reduces the agglomeration. At least Avidin-Biotin, nucleic acids, peptides, and proteins have been used to functionalize graphene oxide.
Graphene oxide works as a fluorescence quenching agent
Fluorescence quenching ability of graphene oxide can be utilized in analyte detection both in solution as well as on the sensor surface where graphene oxide has been deposited. In principle, the GO binds to a dye-labeled aptamer (nucleic acids, peptides) either through covalent or non-covalent binding and quenches the fluorescence of the dye. At the presence of the target molecule, the GO – aptamer interaction is disturbed releasing the dye-labeled aptamer and the fluorescence of dye is restored. Most of the GO-based biosensing systems introduced so far are colloidal suspensions. Ability to integrate GO-based biosensor on solid allows their application in new devices. To be able to utilize graphene oxide on a sensor surface, methods to deposit high quality GO mono- and multilayers are needed.
To read how solution-based graphene oxide deposition can be done, please download the overview below.
Morales-Narváez and A. Morkoci, “Graphene oxide as an optical biosensing platform: A Progress report”, Advanced materials (2018) 1805043.
Ueno, et.al., “On-chip graphene oxide aptasensor for multiple protein detection”, Analytical Chimica Acta 866 (2012) 1.
Sharma, et.al., “Insight into the biosensing of graphene oxide: Present and future prospects”, Arabian Journal of Chemistry 9 (2016) 238.
Graphene oxide (GO) is the oxidized form of graphene. Graphene oxide is easy to process since it is dispersible in water and other solvents. Due to the oxygen in its lattice graphene oxide is not conductive, but it can be reduced to graphene by chemical methods.