Droplet electroporation in microfluidics for efficient cell transformation with or without cell wall removal

Abstract

An efficient cell transformation method is presented that utilizes droplet electroporation on a microfluidic chip. Two types of green microalgae, a wall-less mutant and a wild type of Chlamydomonas reinhardtii, are used as model cells. The PDMS-glass electroporation chip is simply composed of a flow-focusing microstructure for generating cell-encapsulating droplets and a serpentine channel for better mixing of the content in the droplet, and five pairs of parallel microelectrodes on the glass slide, without involving any expensive electrical equipment. The transformation efficiency via the microfluidic electroporation is shown to be more than three orders of magnitude higher for the wall-less mutant, and more than two orders of magnitude higher for the wild type, which has its cell wall intact, than bulk phase electroporation under identical conditions. Furthermore, the microfluidic transformation is remarkably efficient even at a low DNA/cell ratio, facilitating ways of controlling the transgenic copy number, which is important for the stability of the transgene expression.

Electroporation-based applications in biotechnology

“…Thus, it was recently reported that transformation efficiency in thick-walled microalgae can be improved by two orders of magnitude by electroporating them in an optimized microfluidic chamber rather than in cuvettes [83].…”

Pulsed electric field and pH assisted selective extraction of intracellular components from microalgae Nannochloropsis

“…The state of cell walls in strain of microalgae [18] and the composition of a liquid medium used for electroporation [11] may play also an extremely important role. Moreover, even better extraction efficiency may be expected by application of combination of conventional and electrically based techniques.…”

Recent Trends on Micro/Nanofluidic Single Cell Electroporation

“…Droplet microfluidics is potentially applicable for high throughput functional screening of genes, which is not possible in the bulk electroporation process. Recently, Qu et al [76] proposed droplet electroporation with the use of microfluidic device. This device was fabricated with polydimethylsiloxane (PDMS) by using soft lithography process.…”