Biosensors for detection of mercury in contaminated soils.

Biosensors based on whole bacterial cells and on bacterial heavy metal binding protein were used to determine the mercury concentration in soil. The soil samples were collected in a vegetable garden accidentally contaminated with elemental mercury 25 years earlier. Bioavailable mercury was measured using different sensors: a protein-based biosensor, a whole bacterial cell based biosensor, and a plant sensor, i.

Novel synthetic phytochelatin-based capacitive biosensor for heavy metal ion detection.

A novel capacitance biosensor based on synthetic phytochelatins for sensitive detection of heavy metals is described. Synthetic phytochelatin (Glu-Cys)(20)Gly (EC20) fused to the maltose binding domain protein was expressed in Escherichia coli and purified for construction of the biosensor. The new biosensor was able to detect Hg(2+), Cd(2+), Pb(2+), Cu(2+) and Zn(2+) ions in concentration range of 100 fM-10 mM, and the order of sensitivity was S(Zn)>S(Cu)>S(Hg)>>S(Cd) congruent with S(Pb).

Highly Sensitive Novel Biosensor Based on an Immobilized lac Repressor.

Sensitive repressors: The conformational change that occurs in the lac repressor protein when it binds to an inducer molecule has been used to develop a biosensor that permits the detection of the corresponding operator sequence or specific inducer molecules. A capacitive signal transducer was used to translate the conformational change of the lac repressor protein, covalently immobilized on a gold electrode (see schematic representation, A=bound inducer molecule or DNA), into a measurable signal.