Although bacteria play important role in ecological systems and human bodies, they can cause serious problems, like causing water/food contamination and wound infection. Therefore, finding effective and energy efficient antimicrobial approaches is an everlasting effort. Here, we show that locally enhanced electric field treatment (LEEFT) can induce bacteria inactivation with ultrashort (nanosecond) electrical pulses. The bacteria inactivation occurs at the nanowedge tips, which is due to the nano enhanced electric field. Quick pore closure under low voltage confirms that electroporation is the predominant bacteria inactivation mechanism. The advantage of LEEFT is much more significant than bulk electric field treatment (EFT) under nanosecond pulses since nanosecond pulses bacteria could achieve similar inactivation performance as microsecond pulses in LEEFT but could barely work in bulk EFT. Simulation result shows that the transmembrane voltage (TMV) of a cell at nanowedge tip is bult up much faster than that of a cell in bulk space, which is possibly because that the nanowedges are charged much faster than bulk electrode, and the cell membrane is directly charged by the charges concentrated at the nanowedge tip instead of relying on charged ions in the medium. Nanosecond pulses could minimize electrochemical reactions and ROS generation, which lowers the possibility of generating by-products and deteriorating sample quality. It is also a wide spectrum method which works for both Gram positive and negative bacteria, and drug resistant bacteria. The energy consumption analysis of LEEFT and bulk EFT shows that to achieve a similar bacteria inactivation efficiency, the most energy efficient approach is to use nanosecond pulses in LEEFT.

Ultrafast bacteria inactivation achieved by locally enhanced electric field treatment (LEEFT) with nanosecond pulses

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.