Toxicity monitoring is essential for the protection of public health and ecological safety. Microbial fuel cell (MFC) sensors demonstrated good potential in toxicity monitoring, but current MFC sensors can only be used for anaerobic water monitoring. In this study, a novel gas diffusion (GD)-biocathode sensing element was fabricated using a simple method. The GD-biocathode MFC sensor can directly be used for formaldehyde detection (from 0.0005% to 0.005%) in both aerobic and anaerobic water bodies. Electrochemical analysis indicated that the response by the sensor was caused by the toxic inhibition to the microbial activity for the oxygen reduction reaction (ORR). This study for the first time demonstrated that the GD-biocathode MFC sensor has a detection limit of 20 ppm for formaldehyde and can be used to monitor air pollution. Selective sensitivity to formaldehyde was not achieved as the result of using a mixed-culture, which confirms that it can serve as a generic biosensor for monitoring gaseous pollutants. This study expands the realm of knowledge for MFC sensor applications.

毒性监测对于保护公共健康和生态安全至关重要。微生物燃料电池（MFC）传感器在毒性监测中显示出良好的潜力，但是当前的MFC传感器只能用于厌氧水监测。在这项研究中，使用一种简单的方法制造了一种新型的气体扩散（GD）-生物阴极传感元件。GD-生物阴极MFC传感器可直接用于需氧和厌氧水体中的甲醛检测（0.0005％至0.005％）。电化学分析表明，传感器的响应是由对氧还原反应（ORR）的微生物活性的毒性抑制引起的。这项研究首次证明GD-生物阴极MFC传感器对甲醛的检测极限为20 ppm，可用于监测空气污染。使用混合培养的结果未达到对甲醛的选择性敏感性，这证实了它可以用作监测气态污染物的通用生物传感器。这项研究扩展了MFC传感器应用的知识领域。