IMPROVED PLANT TISSUE-BASED BIOSENSOR USING INVITRO CULTURED TOBACCO CALLUS-TISSUE

In vitro cultured tobacco callus tissue, which contains a high activity of peroxidase, was used to construct an amperometric biosensor for the detection of hydrogen peroxide. The tissue was incorporated into a carbon paste matrix along with ferrocene, an electron mediator. The detection of hydrogen peroxide was accomplished through its enzymatic reduction mediated by ferrocene. Comparison studies conducted with normally grown types of tobacco tissues indicate that the callus tissue has the highest biocatalytic activity and the least variance between tissue preparations with respect to sensor response toward hydrogen peroxide. Additionally, the sensor exhibits a remarkably long lifetime of more than 5 months. Other important characteristics of the sensor include fast response times (less than 2 s), wide dynamic range (5 x 10(-6)-1.10 x 10(-4) M) and a detection limit of 7.5 x 10(-7) M hydrogen peroxide.