Oral: 3D-Printing Anthropomorphic Human Phantoms from Polymer Solutions

Phantoms are model systems made from synthetic materials that replicate the structural and material characteristics of biological tissues, providing test environments for a variety of applications ranging from medical imaging to ballistic testing. Hydrogels are often used to mimic the material properties of soft tissues, due to their high-water content and low moduli. However, replicating the internal structural complexities of human tissues with these polymeric materials remains challenging as they are often cast as fluids into predefined molds before undergoing bulk gelation. Advanced manufacturing methods, such as 3D-printing, would enable anthropomorphic phantoms models to be fabricated from tissue-like hydrogels with internal structures that mimic the structural complexities of human tissues. Here, we design poly(vinyl alcohol)-methacrylate polymers with material properties that mimic those of soft tissue. Moreover, we use embedded 3D-printing and support baths of packed granular hydrogel particles to precisely place these polymers in their fluid phases into geometrically complex shapes before inducing gelation. The rheological properties of the PVA solution are tuned independently of the shear modulus of the crosslinked PVA hydrogel networks to increase the viscosity ratios of the ink and support material and control the resulting filament shape. Furthermore, we compare the rheological and thermal properties of 3D-printed PVA hydrogels to analogous samples cast on the benchtop.