Development of a novel conductance-based technology for environmental bacterial sensing  

作　　者：SHEN FangXia TAN MiaoMiao XU Hong XU ZhenCheng YAO MaoSheng 

机构地区：[1]State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University [2]College of Mechanical and Electrical Engineering, Beijing Union University [3]Department of Reproductive Health, Guangdong Women and Children Hospital [4]South China Institute of Environmental Science, Ministry of Environmental Protection

出　　处：《Chinese Science Bulletin》2013年第4期440-448,共9页

基　　金：supported by the National Natural Science Foundation of China (21277007);the National High Technology Research and Development Program of China (2008AA062503);Environment and Health Joint Laboratory at South China Institute of Environmental Science(21111011101EHH(2011)-208)

摘　　要：In this study, a simple impedance based technology for measuring bacterial concentrations was developed. The measurement system includes the signal amplification, copper probes and a sample loader. During the experiments, the conductance of Bacillus subtilis var niger, Pseudomonas fluorescens, and Escherichia coli were measured using the combination of a pre-amplifier and a lock-in amplifier. The conductance data were modeled verses the bacterial concentrations. Results indicated that the relationship between the conductance of bacterial suspensions and their concentrations follows a generic model: Y=C1+C2×e ( X/C3 ) , where Y is the conductance (S), X is the bacterial concentration (Number/mL: abbreviated to N/mL) for all species tested, and C1 3 are constants. Gram negative P. fluorescens and E. coli assumed similar conductance curves, which were flatter than that of gram positive B. subtilis var niger. For P. fluorescens and E. coli the culturing technique resulted in higher concentration levels (statistically significant) from 2 to 4 times that measured by the impedance based technology. For B. subtilis var niger, both methods resulted in similar concentration levels. These differences might be due to membrane types, initial culturability and the obtained conductance curves. The impedance based technology here was shown to obtain the bacterial concentration instantly, holding broad promise in realtime monitoring biological agents.In this study, a simple impedance based technology for measuring bacterial concentrations was developed. The measurement sys- tem includes the signal amplification, copper probes and a sample loader. During the experiments, the conductance of Bacillus subtilis var niger, Pseudomonasfluorescens, and Escherichia coli were measured using the combination of a pre-amplifier and a lock-in amplifier. The conductance data were modeled verses the bacterial concentrations. Results indicated that the relationship between the conductance of bacterial suspensions and their concentrations follows a generic model： Y=C1 ＋ （72 × e（-x/c3）, where Y is the conductance （S）, X is the bacterial concentration （Number/mL： abbreviated to N/mL） for all species tested, and C^-3 are constants. Gram negative P. fluorescens and E. coli assumed similar conductance curves, which were flatter than that of gram positive B. subtilis var niger. For P. fluorescens and E. coli the culturing technique resulted in higher concentration levels （statis- tically significant） from 2 to 4 times that measured by the impedance based technology. For B. subtilis var niger, both methods resulted in similar concentration levels. These differences might be due to membrane types, initial culturability and the obtained conductance curves. The impedance based technology here was shown to obtain the bacterial concentration instantly, holding broad promise in realtime monitoring biological agents.

关 键 词：技术开发 细菌检测 电导数 基础 BACILLUS 细菌浓度 阻抗测量 环境 

分 类 号：Q93-3[生物学—微生物学]