Single cell sorting of young yeast based on label-free fluorescence lifetime imaging microscopy

Saccharomyces cerevisiae is an attractive organism used in the fermentation industry and is an important model organism for virus research. The ability to sort yeast cells is important for diverse applications. Replicative aging of Saccharomyces Cerevisiae is accompanied by metabolic changes that are related to an essential coenzyme, reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H). Here, a single cell sorting method based on fluorescence lifetime imaging microscopy (FLIM) and laser-induced forward transfer (LIFT) was implemented for the first time. The aging level of yeast was determined based on the FLIM by NAD(P)H, which was a label-free and noninvasive method for studying individual cells. Then, young and active yeast cells were sorted by the LIFT system at the single cell level. During the entire experiment, a sterile and humid environment was maintained to ensure the activity of cells. The high viability of sorted cells was achieved by the LIFT combining with FLIM.