Freeze casted microstructured PVA tissue phantoms using a microfabricated seed layer

Improved microstructured PVA phantoms mimicking fibrous tissue have been developed using a modified freeze casting process. In this work we find that by introducing an SU-8 layer containing microfabricated wells of dimensions 10–30 μm, which acts as an ice nucleation seed plate, greater control over the final sample structural properties can be achieved. SEM images reveal highly anisotropic microstructures with controllable pore dimensions between 1–40 μm depending on the seed layer used in the freeze casting process. Preliminary experimental characterization in the range 20–50 MHz reveals a significant dependence of the attenuation coefficient on sample dimension.