Electrochemical biosensing of organophosphates using vertically aligned multiwall carbon nanotubes

Electrochemical biosensors using vertically aligned multiwalled carbon nanotube (VAMWNTs) on the substrates has been envisioned to enhance performance of the sensor. The carboxylated MWNTs were covalently attached to the silicon wafer surface using an amine linkage. MWNTs structure and functionality was characterized using atomic force microscopy (AFM) and resonance Raman spectroscopy. The electrochemical studies of MWNTs showed the excellent electrochemical properties with an electron transfer. In addition to enhanced electron flow, impedance spectroscopy demonstrated the decrease of charge-transfer resistance measurements with the VAMWNTs. Organophosphorus hydrolase (OPH) enzyme was immobilized on the carboxylated VAMWNTs and this nanostructure assembly was used as a sensor to detect organophosphate compounds with high sensitivity.