Oral: Assessing the Rheological Properties of Irradiated 3D Bioprinted Tumor Scaffolds

3D bioprinting enables the creation of tumor models that mimic the complex tumor microenvironment (TME). The TME’s stiffness influences tumor growth, metastasis, and immune response. Radiation therapy (RT) is a common cancer treatment, but its impact on the mechanical properties of tumors remains understudied. This study investigates the biomechanical effects of conventional radiotherapy vs. an emerging approach known as spatially fractionated radiation therapy (SFRT) on 3D-printed tumor scaffold models. Gelatin, alginate, and collagen-based hydrogel scaffolds resembling the mechanical properties of the TME were irradiated with 0, 20, 40, and 60 Gy. The storage modulus (G’), loss modulus (G’’), and tan(δ)=G''/G' were measured as a function of angular frequency to characterize changes in material properties due to ionizing radiation. Preliminary results demonstrate a linear dose-dependent increase in tan(δ). The mean tan(δ) ranged from (9±2)x10^-2 for 0 Gy and (2±1)x10^-1 for 60 Gy. As expected, irradiated samples had a lower G’ and higher G’’ than the 0 Gy controls, which could play a role in tumor cell survival. Further studies with SFRT and larger sample sizes are planned to elucidate the underlying mechanisms and optimize radiation therapy strategies.