Three of the primary bottlenecks, which should be consider for practical, point-of-need use of microbial fuel cell (MFC) analytical devices were surpassed in this work: i) the use of a diffusive barrier, hence, an electrogenic biofilm; ii) longer enrichment/stabilization times to produce a biofilm, made in a laboratory environment, over the electrode; and iii) difficulty comparing results obtained from MFCs based on electrogenic biofilms with standardized bioassays, a setback to be adopted as a new method. Here we show an easy way to determine water toxicity employing planktonic bacteria as biorecognition agents. The paper-based MFC contain an electron carrier (or mediator) to facilitate charge transfer from bacteria to the anode. In this way, there is no need to use biofilms. As far as we know this is the first paper-based MFC containing P. putida KT2440, a well characterized non-pathogenic bacteria previously used in standardized water toxicity bioassays. Results were obtained in 80 min and an effective concentration 50 of 9.02 mg L^-1, calculated for Zn²⁺ (a reference toxic agent), was successfully compared with previously published and ISO standardized bioassays, showing a promising future for this technology. The practical design and cost (less than one U.S. dollar) of the paper-based MFC toxicity test presented will open new market possibilities for rapid and easy-to-use MFC analytical devices.

这项工作超越了三个主要瓶颈，在实际工作中需要考虑使用微生物燃料电池（MFC）分析设备：i）使用扩散屏障，从而形成生物膜。ii）较长的富集/稳定时间，以在实验室环境下在电极上产生生物膜；iii）难以将基于电生物膜的MFC的结果与标准生物测定法进行比较，这是一个挫折，将被采用作为一种新方法。在这里，我们展示了一种使用浮游细菌作为生物识别剂来测定水毒性的简便方法。纸基MFC包含电子载体（或介体），以促进电荷从细菌转移到阳极。这样，无需使用生物膜。据我们所知，这是第一个包含纸张的MFC恶臭假单胞菌KT2440，一种特征明确的非病原细菌，以前用于标准化水毒性生物测定。在80分钟内获得了结果，并将成功计算的Zn ²⁺（一种参考有毒物质）的有效浓度50 9.02 mg L ^-1与先前发布的和ISO标准化的生物测定法进行了比较，表明该技术的前景广阔。提出的纸质MFC毒性测试的实用设计和成本（不到一美元）将为快速，易于使用的MFC分析设备打开新的市场可能性。