• 1 Department of Chemistry, SRM University, Kattankulathur, 603 203, Chennai, India
  • 2 Department of Chemistry, SRM University, Kattankulathur, 603 203, Chennai, India.
  • 3 Environmental Technology Division, School of Industrial Technology, University Sains Malaysia, 11800, Minden, Penang, Malaysia
  • 4 Centre of Bio-Technology, AC Tech, Anna University, Chennai, India
  • 5 Department of Applied Science and Technology, AC Tech, Anna University, Chennai, India
J Fluoresc, 2017 Nov;27(6):2101-2109.
PMID: 28819702 DOI: 10.1007/s10895-017-2149-4


A label -free DNAzyme amplified biosensor is found to be highly selective and sensitive towards fluorescent detection of Pb2+ ions in aqueous media. The DNAzyme complex has designed by the hybridization of the enzyme and substrate strand. In the presence of Pb2+, the DNAzyme activated and cleaved the substrate strand of RNA site (rA) into two oligonucleotide fragments. Further, the free fragment was hybridized with a complementary strand on the surface of MBs. After magnetic separation, SYBER Green I was added and readily intercalate with the dsDNA to gives a bright fluorescence signal with intensity directly proportional to the concentration of Pb2+ions. A detection limit of 5 nM in Pb2+ the detection range 0 to 500 nM was obtained. This label- free fluorescent biosensor has been successfully applied to the determination of environmental water samples. Then results open up the possibility for real-time quantitative detection of Pb2+ with convenient potential applications in the biological and environmental field. Graphical Abstract.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.