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Journal of Sensors
Volume 2015, Article ID 809065, 9 pages
Research Article

Toxicity Biosensor for Sodium Dodecyl Sulfate Using Immobilized Green Fluorescent Protein Expressing Escherichia coli

1Southeast Asia Disaster Prevention Research Initiative (SEADPRI-UKM), LESTARI, National University of Malaysia, 43600 Bangi, Selangor, Malaysia
2Faculty of Science and Technology, National University of Malaysia, 43600 Bangi, Selangor, Malaysia

Received 17 September 2014; Revised 17 December 2014; Accepted 18 December 2014

Academic Editor: Qingjun Liu

Copyright © 2015 Lia Ooi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Green fluorescent protein (GFP) is suitable as a toxicity sensor due to its ability to work alone without cofactors or substrates. Its reaction with toxicants can be determined with fluorometric approaches. GFP mutant gene (C48S/S147C/Q204C/S65T/Q80R) is used because it has higher sensitivity compared to others GFP variants. A novel sodium dodecyl sulfate (SDS) toxicity detection biosensor was built by immobilizing GFP expressing Escherichia coli in k-Carrageenan matrix. Cytotoxicity effect took place in the toxicity biosensor which leads to the decrease in the fluorescence intensity. The fabricated E. coli GFP toxicity biosensor has a wide dynamic range of 4–100 ppm, with LOD of 1.7 ppm. Besides, it possesses short response time (<1 min), high reproducibility (0.76% RSD) and repeatability (0.72% RSD, ), and long-term stability (46 days). E. coli GFP toxicity biosensor has been applied to detect toxicity induced by SDS in tap water, river water, and drinking water. High recovery levels of SDS indicated the applicability of E. coli GFP toxicity biosensor in real water samples toxicity evaluation.