A new method for permeabilization of the plasma membrane of cultured mammalian cells. VII. Permeabilization of growing and resting cells by vortex-stirring with high molecular weight polyacrylic acid.

The permeability of murine leukemia L1210 cells toward non-permeant fluorescent Lucifer Yellow (LY) was evaluated by flow cytometry following vortex-stirring of cells with LY in the presence of high molecular weight polyacrylic acid (A-119). Permeabilization by this technique was greatly enhanced in growth phase cells, whereas it was appreciably reduced in resting cells which had been maintained in unchanged culture medium for 2 to 4d. This reduction in permeabilization of resting cells gradually disappeared when resting cells were re-suspended in fresh culture medium, and the degree of permeabilization was restored to that of the growing cells. It is recommended that the mammalian cells used for internalization of non-permeant materials by vortex-stirring with A-119 should be in the early log phase.