Mapping Spatially Heterogeneous and History-Dependent Hydrogel Mechanics Using Fluid-Driven Cyclic Shear
Year: 2026
Type: preprint
Abstract: Soft porous materials in biological environments, such as the extracellular matrix, are frequently subjected to dynamic stresses transmitted by fluid motion, yet their internal deformation fields and microstructural evolution under repeated loading remain elusive. Here, we impose oscillatory shear on agarose hydrogels without solid contact by embedding a millimeter-scale gel block in a microfluidic channel and applying oscillatory pressure-driven flow over its exposed surface. Tracking fluorescent particles immobilized in the gel reveals a heterogeneous response: displacement increases toward the gel-fluid interface, whereas shear strain and shear rate are concentrated near the anchored base. Under oscillatory flow of constant amplitude and frequency, freshly prepared gels deform progressively less over successive cycles, whereas gels rested for 1 h after gelation maintain a nearly constant deformation amplitude. This temporal response is consistent with bulk rheometry showing increasing storage and loss moduli only in fresh gels. Gels matured under cyclic shear deform less than gels matured at rest for the same duration and, as confocal imaging shows, develop aligned fiber bundles not seen in gels matured at rest. These results show that hydrodynamic loading modulates post-gelation network maturation. This study also establishes this contact-free approach as a platform for studying the mechanics of soft porous materials under flow-induced deformation.
Source: ChemRxiv
Institution: University at Buffalo, State University of New York
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220921595