Molecule transfer into mammalian cells by single sub-nanosecond laser pulses.

A rapid, precise, and viability-retaining method for cytoplasmic molecule delivery is highly desired for cell engineering. Routine methods suffer from low throughput, lack of selectivity, requirement of helper compounds, predominant endosomal delivery, and/or are restricted to specific molecule classes. Photonic cell manipulation bears the potential to overcome these drawbacks. Here we investigated mammalian cell manipulation by single sub-nanosecond laser pulses. Axial beam waist positioning close to a cell monolayer induced culture vessel damage and zones of cell ablation. Cells at margins of ablation zones exhibited uptake of membrane-impermeant fluorophores and GFP expression plasmids. Increasing Rayleigh-length and beam waist diameter reduced the sensitivity to axial defocusing and resulted in robust molecule transfer. Serial application of single pulses focused over a moving cell monolayer yielded quantitative molecule transfer to cells at rates up to 40%. Our results could be basic to spatially and temporally controlled single laser pulse-mediated marker-free high throughput cell manipulation.