Graphene aid for Parkinson's, gout
doi:10.1038/nindia.2011.80 Published online 10 June 2011
Researchers have designed a graphene-modified graphite electrode that could be useful for detecting levels of dopamine and uric acid in bodily fluids and pharmaceutical samples.
Dopamine (DA) is a neurotransmitter found in the central nervous system of many mammals. Abnormal levels of DA in bodily fluids have been linked to Parkinson's disease, Schizophrenia and Huntington's disease. DA coexists with uric acid (UA) and ascorbic acid (AA) in the blood and the central nervous system. Abnormal levels of UA have been linked to gout. Levels of AA and UA are much higher than that of DA and can interfere with the determination of DA.
Electrochemical methods are promising for determining levels of DA, UA and AA. However, using conventional solid electrodes, DA, UA, and AA are oxidized at potentials very close to each other and therefore give overlapping results. To overcome this, the researchers modified a graphite electrode with functionalized graphene. The researchers chose graphene because its electrical conductivity is higher than that of single-walled carbon nanotubes.
Preliminary electrochemical studies showed that the graphene-modified electrode exhibited significant catalytic activity towards DA, UA and AA, compared with that of a bare graphite electrode. The results suggest that simultaneous determination of AA, DA and UA could be possible because the anodic current peaks of these biochemicals are well separated.
The electrode successfully detected levels of DA and UA even in the presence of interfering biomolecules such as sodium chloride, citric acid, glucose and tyrosine, and lost only 3.5% of its initial activity after more than nine successive measurements. It retained 82% of its original activity even after being stored for 20 days.
The researchers say that their graphene-modified electrode is stable and easy to prepare, and that its use in clinical analysis for the determination of DA and UA in the presence of high concentrations of AA is very promising.
- Mallesha, M. et al. Functionalized-graphene modified graphite electrode for the selective determination of dopamine in presence of uric acid and ascorbic acid. Bioelectrochemistry 81, 104-108 (2011)