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Updated: May 14, 2026
An Anaerobic Biosensor Assay for the Detection of Mercury and Cadmium
Published on: December 17, 2018
Label-free chemiresistive biosensor for mercury (II) based on single-walled carbon nanotubes and structure-switching
Ji-Lai Gong1, Tapan Sarkar, Sushmee Badhulika
1Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA ; College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
Abstract:
Herein, we present a sensitive, selective, and facile label-free DNA functionalized single-walled carbon nanotube (SWNT)-based chemiresistive biosensor for the detection of Hg(2+). SWNTs were functionalized with Hg(2+) binding 15-bases long polyT oligonucleotide through covalent attachment using a bilinker molecule. The polyT was further hybridized with polyA to form a polyT-polyA duplex. When exposed to Hg(2+) the polyT-polyA duplex was dehybridized combined with switching of polyT structure, leading to change in resistance/conductance of the SWNT chemiresistor device. The device provided a significant response within 100 to 1000 nM of Hg(2+) concentration with a 6.72 × 10(-3) nM(-1) sensitivity.
