Uria N, Fiset E, Pellitero M Aller, Muñoz F X, Rabaey K, Campo F J Del
Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), 08193, Esfera UAB, 08193, Bellaterra, Barcelona, Spain.
Arkyne Technologies SL (Bioo) ES-B90229261, Carrer de La Tecnologia, 17, 08840, Viladecans, Barcelona, Spain.
Environ Sci Ecotechnol. 2020 Jul 12;3:100053. doi: 10.1016/j.ese.2020.100053. eCollection 2020 Jul.
Microbial biosensors can be an excellent alternative to classical methods for toxicity monitoring, which are time-consuming and not sensitive enough. However, bacteria typically connect to electrodes through biofilm formation, leading to problems due to lack of uniformity or long device production times. A suitable immobilisation technique can overcome these challenges. Still, they may respond more slowly than biofilm-based electrodes because bacteria gradually adapt to electron transfer during biofilm formation. In this study, we propose a controlled and reproducible way to fabricate bacteria-modified electrodes. The method consists of an immobilisation step using a cellulose matrix, followed by an electrode polarization in the presence of ferricyanide and glucose. Our process is short, reproducible and led us to obtain ready-to-use electrodes featuring a high-current response. An excellent shelf-life of the immobilised electrochemically active bacteria was demonstrated for up to one year. After an initial 50% activity loss in the first month, no further declines have been observed over the following 11 months. We implemented our bacteria-modified electrodes to fabricate a lateral flow platform for toxicity monitoring using formaldehyde (3%). Its addition led to a 59% current decrease approximately 20 min after the toxic input. The methods presented here offer the ability to develop a high sensitivity, easy to produce, and long shelf life bacteria-based toxicity detectors.
微生物生物传感器可以成为传统毒性监测方法的绝佳替代方案，传统方法既耗时又不够灵敏。然而，细菌通常通过生物膜形成与电极相连，由于缺乏均匀性或设备生产时间长而导致问题。合适的固定技术可以克服这些挑战。尽管如此，它们的响应可能比基于生物膜的电极更慢，因为细菌在生物膜形成过程中逐渐适应电子转移。在本研究中，我们提出了一种可控且可重复的方法来制造细菌修饰电极。该方法包括使用纤维素基质的固定步骤，然后在铁氰化物和葡萄糖存在下进行电极极化。我们的过程简短、可重复，使我们能够获得具有高电流响应的即用型电极。固定化的电化学活性细菌表现出长达一年的出色保质期。在第一个月最初活性损失50%之后，在接下来的11个月中未观察到进一步下降。我们应用我们的细菌修饰电极制造了一个用于使用3%甲醛进行毒性监测的侧向流动平台。在有毒物质输入后约20分钟，其添加导致电流下降59%。这里介绍的方法提供了开发高灵敏度、易于生产且保质期长的基于细菌的毒性探测器的能力。
