Zinc finger peptide based optic sensor for detection of zinc ions

In the present work, polyacrylamide gel has been used as a matrix for the immobilization of zinc finger peptide and fluorescent dye acrydine orange on the micro well plate to fabricate the fluorescence based biosensor for the detection of zinc ions in milk samples. The fluorescent dye moves in the hydrophobic groove formed after folding of the peptide in the presence of zinc ions. Under optimized conditions, linear range was observed between 0.001 µg/l to 10 µg/l of Zinc ions, with a lowest detection limit of 0.001 µg/l and response time of 5 min. Presented biosensor has shown 20% decrease in fluorescent intensity values after 5 regenerations and stable for more than one month, stored at 4 °C. Interference study with other metal ions like lead, cadmium and copper showed a negligible change in fluorescence intensity in comparison to zinc ions. Developed bio sensing system was found to be novel, quick, reliable, miniaturized, stable, reproducible and repeatable and specific for zinc ion, which has been applied to various milk samples.