Novel method for substance injection into the cell by laser beam--a study of the injection volume

A DNA transfection method by laser microbeam pricking has been recently reported (Kurata, S. et al. Exp. Cell Res. 162, 372 (1986]. The volume of external fluid transferred into the cell by the method was determined through the injection of diphtheria toxin fragment A (Yamaizumi, M. et al. Cell 15, 245 (1978]. Using these results and the results on laser DNA transfection efficiency (Kurata, S. et al. Exp. Cell Res. 162, 372 (1986], the approximate number of DNA molecules necessary to transform the recipient cell was estimated.