ElectroPen: An ultra-low–cost, electricity-free, portable electroporator
(a) Design of the 3D-printed low-cost electroporation device along with a depiction of its size scale, demonstrating portability. The device is operated simply by pressing down the toggle to trigger the piezoelectric mechanism, resulting in electrical discharge. (b) Design of the alternative electroporation millifluidic channel. The millifluidic channel design consists of two blocks (shown here in acrylic) covered with aluminum tape to act as electrodes and placed on a base with a gap distance of 0.1 cm. The millifluidic channel can be built out of other materials (S5 Fig) as an alternative for industrial equivalents. (c) Depiction of the origin of the piezoelectric ignition mechanism found within the common stove lighter. The inset is the striker/piezoelectric mechanism of the lighter. The region with the red cap consists of a metal housing encasing the piezoelectric crystal. The middle black region consists of the spring–latch mechanism that strikes the crystal. The bottom black region (rightmost) consists of a wedge that is the origin for user-applied force and triggers the spring mechanism. The toggle on a lighter directly exerts a force on this mechanism to produce a spark. (d) Illustration of the general protocol for using the ElectroPen system. The cellular suspension is added to the gap in the millifluidic channel, after which the ElectroPen is connected and pressed to trigger a voltage potential. The cell suspension is then recovered in Luria Bertani broth and plated. See S1 Video for a detailed demonstration. (e) Illustration of the individual components of the 3D-printed ElectroPen platform and custom millifluidic channel. The CAD (.stl) file for the casing can be found on GitHub. CAD, computer-aided design; GFP, green fluorescent protein; pGFP, plasmid GFP.