%0 Journal Article
%T Whole Cell Biosensor Using Anabaena torulosa with Optical Transduction for Environmental Toxicity Evaluation
%A Ling Shing Wong
%A Yook Heng Lee
%A Salmijah Surif
%J Journal of Sensors
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/567272
%X A whole cell-based biosensor using Anabaena torulosa for the detection of heavy metals (Cu, Pb, and Cd), 2,4-dichlorophenoxyacetate (2,4-D), and chlorpyrifos was constructed. The cyanobacteria were entrapped on a cellulose membrane through filtration. Then, the membrane was dried and fixed into a cylindrical well, which was designed to be attached to an optical probe. The probe was connected to fluorescence spectrometer with optical fibre. The presence of the toxicants was indicated by the change of fluorescence emission, before and after the exposure. The linear detection ranges for Cu, Pb, and Cd were 2.5每10.0ˋ米g/L, 0.5每5.0ˋ米g/L, and 0.5每10.0ˋ米g/L, respectively, while 2,4-D and chlorpyrifos shared similar linear ranges of 0.05每0.75 米g/L. The biosensor showed good sensitivity with the lowest limits of detection (LLD) for Cu, Pb, Cd, 2,4-D and chlorpyrifos determined at 1.195ˋ米g/L, 0.100ˋ米g/L, 0.027ˋ米g/L, 0.025ˋ米g/L, and 0.025ˋ米g/L, respectively. The overall reproducibility of the biosensor ( ) was <㊣6.35%. The biosensor had been tested with different combinations of toxicants, with the results showing predominantly antagonistic responses. The results confirmed that the biosensor constructed in this report is suitable to be used in quantitative and qualitative detections of heavy metals and pesticides. 1. Introduction Industrial and agricultural activities release tonnes of heavy metals and pesticides into the environment. With all these toxicants widespread and threatening the safety of environment, the development of sensitive and fast responding detection devices, which can respond to these toxicants, is pressingly needed. Conventional analytical equipment for heavy metals and pesticides detection, such as high-performance chromatography and atomic absorption spectrometer is not designed to distinguish whether the toxicants are bioavailable or nonbioavailable to biological systems [1]. In contrast, biosensors are capable of showing the real impact of environment toxicants on living organisms [2, 3]. Whole cell biosensors can be used to detect wide range of changes in the environment and are suitable to be used for the detection of toxicants in the sample from unpredictable resources [4]. Few of the cells＊ responses that have been utilized in whole cell biosensors are the oxygen release [5], fluorescence emission [6], and enzyme production [7]. The high sensitivity of certain cells to the environmental toxicants such as heavy metals and pesticides has made them good candidates in biosensors [8每11]. By far, some whole cell biosensors have been
%U http://www.hindawi.com/journals/js/2013/567272/