Photo-transfection of mammalian cells via femtosecond laser pulses

Abstract

Various methods including chemical, viral or physical approaches have been developed to trigger transient membrane permeabilisation with limited cytotocixity in cells. Such developments permit efficient cytoplasmic delivery of genes, fluorochromes, antibodies etc. which are essential for research in subject areas such as genetics, cell biology and clinical therapy. Genetic species can be exclusively introduced and subsequently expressed in live mammalian cells via optical systems, a technique presently referred to as photo-transfection. Localised application of femtosecond (fs) laser pulses onto the cell membrane induces transient submicrometer holes, thereby facilitating cytosolic uptake of extracellular exogenous materials. In this work we report on transient photo-transfection of ovary (CHO-Kl), neuroblastoma (NG-I08 & SKN-SH) and embryonic kidney (HEK-293) as well as primary non-differentiated stem cells (EI4g2a) using a tightly focused titanium sapphire laser beam (1.1 urn diameter spot size). Transfection efficiencies between 40 - 63 % are recorded. We show for the first time that, due to their different sensitivity, surface receptors and membrane structure the cell lines mentioned above displayed varying photo-transfection efficiencies at different subculture "passage" numbers.