组成图示
示意图生成中
传感器类型
电化学生物传感器
检测对象
溶解氧（DO）、生化需氧量（BOD）；样品基质为含Bacillus subtilis或Candida humicola的培养液/水样
检测原理
该生物传感器以溶解氧（DO）为被测物，以微生物耗氧引起的DO下降反映生化需氧量（BOD）。样品中的O2穿过硅（Si）扩散膜进入氯化钾（KCl）电解质，在铂（Pt）阴极发生还原反应：O2+2H2O+4e−→4OH−。生成的OH−迁移至银（Ag）阳极，与Ag反应生成Ag2O并释放电子，形成闭合电流回路。电极电流经放大后转换为DO浓度；微生物代谢消耗O2使DO随时间下降，BOD曲线反映耗氧速率。Cd(II)通过抑制或促进微生物生长改变耗氧强度，从而改变BOD信号。该过程无核酸或酶催化放大，主要依靠电流放大提高信噪比。
检测灵敏度
原文未报告LOD、线性范围、灵敏度斜率或相关系数。
效应效果
本文以PASCO CI-6542溶解氧传感器监测微生物培养液中的DO和BOD，未报告LOD、线性范围、回收率或与ELISA/HPLC/qPCR的对比。文中提及的酶电极生物传感器响应时间<1 min，重现性RSD=2.38%（n=6），2个月后保留85%初始灵敏度。实验显示Cd(II)低浓度促进Bacillus subtilis和Candida humicola生长，高浓度分别抑制Bacillus subtilis（240–480 μg/mL）和Candida humicola（1600–3200 μg/mL）；BOD随世代时间呈回归变化，Candida humicola衰亡期平均BOD为6.52 mg/mL。UV、pH与微热量曲线趋势一致，说明该组合可用于环境毒理学评估。
传感器的构成
- 换能器阴极：铂（Pt）阴极，溶解氧在其表面还原为OH−并产生电流
- 对电极阳极：银（Ag）阳极，OH−与Ag反应生成Ag2O并释放电子
- 电解质层：氯化钾（KCl）电解质溶液，传导离子并维持电极反应
- 扩散膜：硅（Si）薄膜，允许溶解氧选择性扩散进入电解质
- 样品介质：含溶解氧的水样或微生物培养液，提供O2并反映微生物耗氧
- 信号读出：PASCO CI-6542溶解氧传感器及数据采集系统，将电流放大并转换为DO/BOD信号
中文摘要
本研究基于微生物产热的微热量法，评估Cd(II)对枯草芽孢杆菌（Bacillus subtilis）和土生假丝酵母（Candida humicola）生长代谢的影响。采用TAM III微热量仪和安瓿瓶法，在28 ℃下记录两种微生物生长代谢的功率-时间曲线，并测定生长期最大峰热功率（Pmax）、生长速率常数（k）、对数期热效应（Qlog）和总热效应（QT）。同时利用生物传感器监测溶解氧和生化需氧量（BOD）。结果表明，不同浓度Cd(II)对两种微生物具有不同效应：较高浓度抑制Candida humicola（1600–3200 μg·mL−1）和Bacillus subtilis（240–480 μg·mL−1）生长，较低浓度则促进二者生长。细胞干重变化与生长时间一致；两种微生物的BOD随世代时间均呈回归变化。紫外分光光度计和精密pH计测得的生长曲线与微热量仪测得的热力学曲线趋势一致，说明微热量法与生物传感器技术可互补地反映Cd(II)对纯微生物的毒性效应。
英文摘要
A microcalorimetric technique based on microbes heat-output was explored to evaluate the effect of Cd (II) on Bacillus subtilis and Candida humicola. The power-time curves of the growth metabolism of Bacillus subtilis and Candida humicola and the effect of Cd (II) on it were studied by using a TAM III microcalorimeter, ampoules method at 28 degrees C. For the evaluation of toxic effect on pure micro-organisms, the maximum peak-heat output power (P(max)) in the growth phase, the growth rate constants (k), the log phase heat effects (Q(log)), and the total heat effect (Q(T)) for Bacillus subtilis and Candida humicola were determined. Dissolved oxygen and biochemical oxygen demand (BOD) were evaluated by a biosensor. Cadmium has been regarded as the essential biological trace element. Cd (II) solutions of different concentration have different effects on Bacillus subtilis and Candida humicola growth metabolism. The higher concentrations of Cd (II) inhibit the growth of Candida humicola (1600-3200 microg.mL(-1)), Bacillus subtilis (240-480 microg.mL(-1)); the lower concentrations can promote the growth of both micro-organism. The values of cell dry weight is also showed in conformity in the cell dry weight changes to the micro-organisms' growth time. Comparison of growth curves of two micro-organisms showed that both the trends of biochemical oxygen demand were exhibiting regressive changes with the passage of time during their generation times (t(G)). Results from ultraviolet spectrophotometer and precision pH meter all showed that the control growth curves were visioning same trends with the thermodynamic curves of micro-organisms measured by microcalorimeter.