Damgaard L R, Revsbech N P
Department of Microbial Ecology, University of Aarhus, Bygn. 540 Ny Munkegade, DK-8000 Aarhus C, Denmark.
Anal Chem. 1997 Jul 1;69(13):2262-7. doi: 10.1021/ac9611576.
A microscale biosensor for continuous measurement of methane partial pressure based on a novel counterdiffusion principle is presented. Methane-oxidizing bacteria placed in the microsensor utilize oxygen from an internal oxygen reservoir when methane from the exterior diffuses through the tip membrane. The transducer is an internal oxygen microsensor with its tip positioned between the oxygen reservoir and the sensor tip membrane. The external partial pressure of methane determines the rate of bacterial oxygen consumption within the sensor, which in turn is reflected by the signal from the transducer. Tip diameters were down to 20 μm, enabling us to study methane distribution on a microscale. The microscale construction also results in a low stirring sensitivity and a 95% response time down to 20 s. By tailoring the geometry, sensors can be made to exhibit a linear response in the full range of 0-1 atm partial pressure of methane or, alternatively, to exhibit a linear response only at lower concentrations, improving the sensitivity to below 0.1 kPa, corresponding to ∼1 μM in aqueous solution. Temperature, oxygen, and H(2)S interfere with the signal; no interferences were detected from H(2), NH(3), CO(2), or acetate.
本文介绍了一种基于新型反向扩散原理的用于连续测量甲烷分压的微型生物传感器。置于微传感器中的甲烷氧化细菌，当外部的甲烷通过尖端膜扩散进来时，会利用内部氧气储备中的氧气。该传感器是一个内部氧气微传感器，其尖端位于氧气储备和传感器尖端膜之间。甲烷的外部分压决定了传感器内细菌的耗氧速率，这又通过传感器的信号反映出来。尖端直径小至20μm，使我们能够在微观尺度上研究甲烷分布。这种微观结构还导致低搅拌灵敏度和低至20s的95%响应时间。通过调整几何形状，传感器可以在甲烷分压0 - 1个大气压的整个范围内呈现线性响应，或者仅在较低浓度下呈现线性响应，从而将灵敏度提高到低于0.1kPa，这相当于水溶液中约1μM的浓度。温度、氧气和H₂S会干扰信号；未检测到来自H₂、NH₃、CO₂或乙酸盐的干扰。
