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Zhang Y, Ren T, Tian H, Jin B, He J. Hydrogel-Encapsulated Enzyme Facilitates Colorimetric Acute Toxicity Assessment of Heavy Metal Ions. ACS APPLIED MATERIALS & INTERFACES 2018; 10:26705-26712. [PMID: 30058794 DOI: 10.1021/acsami.8b08949] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Conventional analysis of heavy metal ions in water requires highly skilled staff and sophisticated equipment. These limitations make conventional approaches difficult to perform analysis on-site without delay. Herein, we report a facile colorimetric sensing system developed for acute toxicity assessment of heavy metal ions. A bioactive enzyme, β-galactosidase, was used as sensing agent rather than bacteria or other higher organisms to improve selectivity and response time. The developed bioassay is capable of assessing the toxicity of heavy metal ions such as Hg(II), Cd(II), Pb(II), and Cu(II). The effects of enzyme concentration on the assessing performances (i.e., sensitivity and response time) of bioassay were explored and illustrated. Generally, low enzyme concentration facilitates sensitivity enhancement, achieving a 50% inhibiting concentration (IC50) of 0.76 μM (=152 ppb) Hg(II), and high enzyme concentration ensures quick response, enabling a response time down to 9 min. Moreover, the enzyme and substrate were respectively encapsulated by hydrogel to further simplify the assay procedure and enhance the stability of the enzyme. The hydrogel-encapsulated enzyme worked well even when heated up to 60 °C and retained ca. 90% activity after storage for 5 months. Moreover, the developed toxicity-assessing system is feasible for assessing toxicity of actual water samples. This assay approach is low cost and time effective and has no potential ethic issues. In addition, this work paves the way for the development of toxicity assessment kits for on-site analysis based on functional bioactive molecules.
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Affiliation(s)
- Yue Zhang
- Functional Nanomaterials Laboratory, Center for Micro/Nanomaterials and Technology and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Zhongguancundonglu 29 , Haidianqu, Beijing 100190 , China
| | - Tingting Ren
- Functional Nanomaterials Laboratory, Center for Micro/Nanomaterials and Technology and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Zhongguancundonglu 29 , Haidianqu, Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100864 , China
| | - Hua Tian
- Functional Nanomaterials Laboratory, Center for Micro/Nanomaterials and Technology and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Zhongguancundonglu 29 , Haidianqu, Beijing 100190 , China
| | - Binbin Jin
- Functional Nanomaterials Laboratory, Center for Micro/Nanomaterials and Technology and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Zhongguancundonglu 29 , Haidianqu, Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100864 , China
| | - Junhui He
- Functional Nanomaterials Laboratory, Center for Micro/Nanomaterials and Technology and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Zhongguancundonglu 29 , Haidianqu, Beijing 100190 , China
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Chapleau RR, Blomberg R, Ford PC, Sagermann M. Design of a highly specific and noninvasive biosensor suitable for real-time in vivo imaging of mercury (II) uptake. Protein Sci 2008; 17:614-22. [PMID: 18305194 DOI: 10.1110/ps.073358908] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Mercury is a ubiquitous pollutant that when absorbed is extremely toxic to a wide variety of biochemical processes. Mercury (II) is a strong, "invisible" poison that is rapidly absorbed by tissues of the intestinal tract, kidneys, and liver upon ingestion. In this study, a novel fluorescence-based biosensor is presented that allows for the direct monitoring of the uptake and distribution of the metal under noninvasive in vivo conditions. With the introduction of a cysteine residue at position 205, located in close proximity to the chromophore, the green fluorescent protein (GFP) from Aequorea victoria was converted into a highly specific biosensor for this metal ion. The mutant protein exhibits a dramatic absorbance and fluorescence change upon mercuration at neutral pH. Absorbance and fluorescence properties with respect to the metal concentration exhibit sigmoidal binding behavior with a detection limit in the low nanomolar range. Time-resolved binding studies indicate rapid subsecond binding of the metal to the protein. The crystal structures obtained of mutant eGFP205C indicate a possible access route of the metal into the core of the protein. To our knowledge, this engineered protein is a first example of a biosensor that allows for noninvasive and real-time imaging of mercury uptake in a living cell. A major advantage is that its expression can be genetically controlled in many organisms to enable unprecedented studies of tissue specific mercury uptake.
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Affiliation(s)
- Richard R Chapleau
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106-9510, USA
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Han S, Zhu M, Yuan Z, Li X. A methylene blue-mediated enzyme electrode for the determination of trace mercury(II), mercury(I), methylmercury, and mercury-glutathione complex. Biosens Bioelectron 2001; 16:9-16. [PMID: 11261858 DOI: 10.1016/s0956-5663(00)00114-7] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A methylene blue-mediated enzyme biosensor has been developed for the detection of inhibitors including mercury(II), mercury(I), methylmercury, and mercury-glutathione complex. The inhibition to horseradish peroxidase was apparently reversible and noncompetitive in the presence of HgCl2 in less than 8 s and irreversibly inactivated when incubated with different concentrations of HgCl2 for 1-8 min. The binding site of horseradish peroxidase with HgCl2 probably was a cysteine residue SH. Mercury compounds can be assayed amperometrically with the detection limits 0.1 ng ml(-1) Hg for HgCl2 and methylmercury, 0.2 ng ml(-1) Hg for Hg2(NO3)2 and 1.7 ng ml(-1) Hg for mercury glutathione complex. Inactivation of the immobilized horseradish peroxidase was displayed in the AFM images of the enzyme membranes.
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Affiliation(s)
- S Han
- Department of Chemistry, Graduate School, University of Science and Technology of China, Chinese Academy of Sciences, Beijing, People's Republic of China
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SCHELLER FRIEDERW, KLEINJUNG FRANK, BIER FRANKF, MAKOWER ALEXANDER, NEUMANN BARBARA, WOLLENBERGER ULLA, KUROCHKIN ILIYA, EREMENKO ARKADI, BARMIN ANATOLI, KLUbetaMANN SVEN, FURSTE JENSPETER, ERDMANN VOLKERA, MANSUY D. New Recognition Elements in Biosensing. Ann N Y Acad Sci 1998. [DOI: 10.1111/j.1749-6632.1998.tb10286.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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