Jul 14, 2014
Selective electrochemical biosensing using molybdenum disulfide
Neurotransmitters, such as dopamine (DA), play a key role in the motor and cognitive functions of humans and animals. The depletion of DA can cause Parkinson’s disease, yet abnormally high dopaminergic neurotransmission is associated with schizophrenia and Tourette’s Syndrome. Methods to detect this with high sensitivity are therefore needed. Reporting in Nanotechnology, researchers have employed ultrathin molybdenum disulfide (MoS2) for the first time as an electrode material for the electrochemical biosensing of both neurotransmitters and glucose.
Atomically thin MoS2 sheets are synthesized and isolated via solvent-assisted chemical exfoliation. Layered transition metal dichalcogenides are being extensively researched due to their structural similarities with graphene and interesting physico-chemical properties. This is in addition to their exotic electronic properties. MoS2 is an extensively studied material and has already shown promising applications in electronics and optoelectronics fields.
Here, electrochemical enzymatic and non-enzymatic biosensing studies using ultrathin MoS2-based electrodes unravel the potential of these electrodes. DA always co-exists with its common interferent ascorbic acid (AA) and both of them undergo oxidation at a similar potential under physiological conditions. As the concentration of AA is always higher than that of DA, the reliable measurement and quantification of DA is difficult. The existence of surface negative charges on MoS2 discriminates or eliminates the interference of AA. An extensive study on various redox probes using MoS2 indicates that MoS2 electrodes can be extended to the selective detection of other charged biomolecules.
Further, it is demonstrated that the entire MoS2 surface is in a favourable geometry to accommodate enzymes, thereby opening up the possibility for highly sensitive enzymatic biosensing applications. Currently, the authors are investigating the possibility of designing flexible sensors using MoS2 sheets for point-of-care diagnosis.
More information about the research can be found in the journal Nanotechnology 25 335702.
About the author
The lead authors TN Narayanan and A Subbiah are working as scientists at CSIR-Central Electrochemical Research Institute (CSIR-CECRI), Karaikudi, India. TN Narayanan received his PhD from Cochin University of Science and Technology, Kerala, India. Following this, he spent three years at Rice University, Houston, Texas, USA, as a postdoctoral researcher. His expertise is in the broad areas of functional nanomateirals and their applications. Subbiah obtained his PhD from Macquarie University, Sydney, Australia. Later, he held various positions in the United States for about seven years at the University of Iowa, Florida International University and the University of South Florida. His expertise is in the area of ultra-microelectrodes, electrochemical nanobiosensors/devices for clinical applications. The other co-author CSR Vusa is a graduate student at CSIR-CECRI.