Viscoelastic Response of Alginate-Gelatin Hydrogel Tissue Models Following Spatially Fractionated GRID Irradiation
Abstract
Purpose
While the biological impacts of ionizing radiation are well-documented, its effects on the viscous and elastic (rheological) properties of the gel remain under-explored. This study addresses this gap by investigating how high dose spatially fractionated GRID radiation alters the rheological properties of a hydrogel used to mimic the tissue microenvironment in 3D bioprinting.
Methods
Hydrogels composed of 1% alginate and 7% gelatin (w/v) were prepared in the shape of a flat disc (8 mm diameter, 1 mm thickness). They were crosslinked using calcium chloride. One group served as the control (0 Gy), and the other was irradiated (60 Gy) using an in-house GRID collimator. Rheological measurements of the storage (elastic) and loss (viscous) moduli of the hydrogel were made using a TA Instruments DHR-3 Digital Hybrid Rheometer. Data was summarized by averaging over frequency sweeps between 0.1 Hz and 100 Hz. The ratio of the loss modulus to the storage modulus, the tan(delta), was computed.
Results
The data showed a statistically significant 18% decrease in the average storage modulus of the irradiated samples (p=0.001). No significant change was observed in the loss modulus or tan(delta).
Conclusion
This work indicates that ionizing radiation delivered in a GRID pattern has statistically significant effects on the storage modulus of alginate-gelatin hydrogels. Further study is planned on cell-laden hydrogel samples using lower 20 Gray doses.