Abstract:
The introduction of nanoparticles to intact plant cells is promising as a transporting technique of a wide range of functional molecules.
Among various molecular delivery methods, femtosecond laser photoinjection possesses target selectivity at a single cell level and is potentially
applicable for many types of materials. However, for plant cells, the vacuoles’ turgor pressure and the thick cell wall limit the application of
photoinjection to only small objects. In this work, we overcome these limitations by employing a single pulse irradiation from a femtosecond
laser amplifier. After laser irradiation on intact tobacco BY-2 cells, 80 nm fluorescent nanoparticles dispersed in a cell culture medium were
successfully injected into their cytoplasm. This breakthrough would lead to a vast utilization of nanoparticles containing functional molecules
for single cell manipulation in plant physiological study and genetic engineering. Such an injection was observed even when the laser pulse
was focused neither on the cell wall nor on the cell membrane, but beside the cells. With these results, we suggest pore formation on the cell
membrane by instantaneous deformation induced by an intense femtosecond laser pulse as an injection mechanism of nanoparticles. Reported
photomechanical effects of the amplified femtosecond laser on the permeability of the biological membrane would offer new perspectives in
biophotonics.