Application of Multi walled Carbon Nanotubes (MWCNTs) in Phenol biosensor based on bacterial cells

In recent years, electrochemical detection techniques have proved quite promising since they are simple, fast and cost effective. Up to date, some electrochemical biosensors based on enzymes and microorganisms have been fabricated for the detection of phenol as a priority pollutant listed by the United States Environmental Protection Agency (USEPA). MWCNTs have been widely considered as attractive materials due to their high electrical conductivity, chemical stability and extremely high mechanical strength. The presented work includes the development of a fast, sensitive and miniaturized microbial conductometric biosensor for the determination of phenol based on the cells of Pseudomonas sp. (GSN23) and modified microelectrodes with MWCNTs.

Cells of Pseudomonas sp. (GSN23) were grown in the presence of phenol as the sole source of organic carbon and adapted cells were immobilized on the surface of gold interdigitated microelectrodes. Carbon nanotube (CNT) - modified microelectrodes were also prepared to test nanoparticle effect on the efficiency of biosensor performance.

From the results obtained with conductometric measurement, sensitive detection of phenol from 1 to 300 mg.L-1 (10-3187 µM), was estimated. Furthermore, substrate specificity and operational stability were investigated. Discussion and

The proposed system does not require any complex immobilization procedures and showed the linearity and repeatability with a high operational stability. The use of optimum amounts of MWCNTs and phenol adapted bacteria provide better sensor sensitivity by promoting the ions transfer within the structure of the biosensor