Microbial biofilms for self-powered noncontact sensing

Noncontact sensing technology plays a vital role in the intelligent human–machine interface, as the essential medium for exchanging information between human and electronic devices. To date, several inorganic materials-based noncontact sensing techniques have been used to accurately detect touch, electrical property, and physical motion. However, limited available materials, dependence on additional power supplies, and poor power production performance, have seriously obstructed the practical applications of noncontact sensing technology. Here, we developed simple self-powered noncontact sensors (SNSs) assembled using a typical G. sulfurreducens biofilm as the core component. In noncontact mode, the sensor demonstrated excellent self-powered sensing performance with maximum voltage output of 10 V and a current of 60 nA, a maximum sensing range of 40 cm which is the farthest reported to date. Depending on its excellent sensing characteristic, the SNSs was used to monitor human breathing in this work. Furthermore, an array of united SNSs was able to localize external electric fields and effectively extend the sensing area by increasing the number of devices. Compared to traditional inorganic materials, microbial biofilms have the advantages of wide existence, self-proliferation, low cost, environmental friendliness, and ultra-fast self-healing property (seconds level). The proposed biofilm SNSs in our work provides new insights for noncontact power generation of biomaterials and self-driven sensing.