Real-time quantitative measurement of mechanical properties of spherical hydrogels during degradation by hydrodynamic loading and numerical simulation

Abstract

Recently, spherical hydrogels have been widely used in food, biology, and medicine fields. It is critical to accurately measure the mechanical properties of spherical hydrogels, which is the foundation of the application performances. However, an appropriate method for real-time quantitative detection of soft spherical hydrogels is still lacking. In this study, a novel method combining hydrodynamic loading experiments and numerical simulation (HD-NS) was proposed. The hydrodynamic loading experiments were implemented to drive spherical hydrogels into a contraction channel by fluid force. Based on the experimental results, the computational fluid dynamics simulation and finite element simulation were carried out to calculate the fluid force and apparent modulus of spherical hydrogels. The efficiency and accuracy of the HD-NS method were verified by measuring the apparent modulus of composite spherical hydrogels composed of konjac glucomannan, sodium alginate, and carrageenan with various apparent modulus changing from 8.93 kPa to 35.75 kPa. Then HD-NS method was applied to real-time measure the deformation and apparent modulus of spherical hydrogels during degradation. The result showed that with the degradation time increasing or the solution pH decreasing, the spherical hydrogels showed looser microstructure and gradually decreasing apparent modulus from 30.48 kPa to 9.14 kPa. These results provide more understanding of the relationships between degradation level, microstructure, and mechanical properties of spherical hydrogels during degradation. The study will promote the development and application of degradable spherical hydrogels with precisely regulated mechanical properties such as artificial blood cells and injectable and edible drug sustained-release carriers.