  We expose thick polymer foam tissue scaffolds to high power ultrasound and
study its effect on the openness of the pore architecture and fluid transport
through the scaffold. Our analysis is supported by measurements of fluid uptake
during insonification and imaging of the scaffold microstructure via x-ray
computed tomography, scanning electron microscopy and acoustic microscopy. The
ultrasonic treatment is found to increase the mean pore size by over 10%. More
striking is the improvement in fluid uptake: for scaffolds with only 40% water
uptake via standard immersion techniques, we can routinely achieve full
saturation of the scaffold over approximately one hour of exposure. These
desirable modifications occur with no loss of scaffold integrity and negligible
mass loss, and are optimized when the ultrasound treatment is coupled to a
pre-wetting stage with ethanol. Our findings suggest that high power ultrasound
is a highly targetted and efficient means to promote pore interconnectivity and
fluid transport in thick foam tissue scaffolds.
