Paper-Based Microfluidic Continuous-Flow Electroporation (μCEP) for Bacterial Transformation through Pore-Scale Electric-Field Enhancement

Electroporation (EP) is an established method for introducing biomolecules such as DNA into bacterial cells. Commercially available cuvette-based EP systems are expensive to use and limited to small sample volumes making them impractical for high-throughput applications. Furthermore, high electric fields are required in these systems which can promote electrolysis and Joule heating, thereby reducing cell viability. Herein, we report a scalable, low-cost technique called Microfluidic Continuous-Flow Electroporation in Paper (CEP) which takes advantage of the insulating nature of glass fiber paper and its micron-sized pores to amplify the electric field strength experienced by cells. The CEP device is fabricated by sealing glass fibers between PDMS membranes using a combination of corona plasma treatment and heat-pressing. Our results demonstrate that the CEP technique enables transformation of E. coli at lower applied electric field strengths with transformation efficiencies comparable to or higher than those of cuvette-based EP under the tested conditions. The continuous-flow format and lower required applied field provides a low-cost approach to bacterial electroporation while maintaining cell viability comparable to that of conventional cuvette-based EP.