Passive entry of a DNA molecule into a small pore.

I consider a vesicle with an open pore of small radius rp, exposed to a DNA solution. The crucial moment is the entry, when a chain end faces the pore and enters it. I discuss qualitatively the following three characteristic times: (i) the duration of the entry of one chain end (defining the minimum lifetime of the pore) taue approximately 10(-4) sec, (ii) the transfection time taut (the time required to be sure that one chain has gone in) taut approximately hours, and (iii) the sliding time tauS (the time between entry of one end and entry of the other end) approximately 1 sec. A fortunate feature is that sliding may proceed even if the pore tends to close itself after entry.