Development of MWNT based disposable biosensor on glassy carbon electrode for the detection of organophosphorus nerve...

The development of a disposable Acetylcholinesterase (AChE) based biosensor is described. Synthesis, purification and further functionalization with oxygen containing hydrophilic functional groups of Carbon nanotubes (CNTs) have been detailed. Biosensing activity of functionalized multi walled carbon nanotubes (MWNTs) towards the detection of Organo phosphorus (OP) compound, paraoxon, has been tested using Amperometric method. Functional groups on the surface of MWNTs creates favorable surface for enzyme immobilization and enhances the enzyme electrode interaction by increasing the electron transfer rate due to high electrical conductivity of the MWNTs. Inhibition of AChE by paraoxon is determined by the decrease in catalytic activity of AChE. This results in less production of enzymatic product thiocholine, which leads to reduction in the electroxidation current. The ability of MWNTs based sensor to reliably measure concentration in the range 7 to 0.5 nM has been demonstrated. The detection limit of biosensor has been found to be as low as 0.5 nM.