Protoplasts on-chip: State-of-the-art and current progress

Protoplasts are plant cells that have been isolated from plant tissue by having their cell walls enzymatically removed. The ability of single protoplasts to be regenerated into a full plant makes them an important part of both fundamental developmental studies and applied agricultural research. Conventional protoplast culture techniques are carried out at plate-scale. This makes the stimulation and tracking of individual cells very difficult and forces researchers to instead rely on population averages. Microfluidic techniques offer a solution in which researchers can stimulate and observe individual protoplasts, even opening the door to novel techniques that are impossible with conventional plate-scale equipment. The study of protoplasts on-chip is a relatively new, yet rapidly developing, field of research, targeting a wide range of different final applications. In this review we show the recent developments of protoplast on-chip research, focusing on major sub-topics such as fusion of protoplasts, lysate analysis, cytometry & sorting, culturing & regeneration and stimulus response. Taken together, this collection of works highlights the potential of this growing domain of protoplast research.