a selective high intensity ultrasonic foaming technique is described to fabricate porous polymers for biomedical applications . process variables , including ultrasound power , scanning speed , and gas concentration have an affect on pore size . pore size can be controlled with the scanning speed of the ultrasound insonation and interconnected porous structures could be obtained using a partially saturated polymers . a gas concentration range of 3 - 5 % by weight creates interconnected open - celled porous structures . the selective high intensity ultrasonic foaming method can be used on biocompatible polymers so as not to introduce any organic solvents . the method has use in cell related biomedical applications such as studying cell growth behaviors by providing a porous environment with varying topological features .