We next explored how immobilized liposomes could be released from AAO pores. As shown in Figure , almost no release of NBD-liposomes was observed when the buffer solutions added with liposome-immobilized AAO were either vigorously agitated by vortex or heated at 50C for 24 h. The amount for released liposomes was comparable to that for simple incubation at room temperature for 24 h. In contrast, we found that ultrasonic irradiation enabled rapid and efficient release of the NBD-liposomes from the AAO pores. Even one- minute ultrasonication resulted in yielded 20-fold higher release of NBD-liposomes compared to the above treatments. Longer ultrasonication duration did not lead to further release of liposomes (Figure ), so that ultrasonication for one minute is enough for the liposome release from AAO pores. Significantly, the release efficiency was unchanged after the immobilized AAO membranes were incubated in the buffer for one week (Figure ). These results show that AAO membranes hold potential as platforms to allow on-demand release of liposomes by ultrasonic irradiation. The observed release of the liposomes from AAO pores is highly likely ascribed to cavitation effect caused by ultrasound irradiation. Pressure and heat generated by cavitation could have torn off the liposomes from the pore surface and flushed them out.