Dynamic loading of deformable porous media can induce active solute transport

Abstract

Active solute transport mediated by molecular motors across porous membranes is a well-recognized mechanism for transport across the cell membrane. In contrast, active transport mediated by mechanical loading of porous media is a non-intuitive mechanism that has only been predicted recently from theory, but not yet observed experimentally. This study uses agarose hydrogel and dextran molecules as a model experimental system to explore this mechanism. Results show that dynamic loading can enhance the uptake of dextran by a factor greater than 15 over passive diffusion, for certain combinations of gel concentration and dextran molecular weight. Upon cessation of loading, the concentration reverts back to that achieved under passive diffusion. Thus, active solute transport in porous media can indeed be mediated by cyclical mechanical loading.

Dynamic Mechanical Loading Enhances Functional Properties of Tissue-Engineered Cartilage Using Mature Canine Chondrocytes

“…32 Applied DL provides a physical stimulus to chondrocytes in addition to enhanced nutrient transport. 23,59 Sliding contact, which simulates aspects of joint articulation, has shown promise in promoting engineered tissue development 60,61 and provides an alternative option for FTE of cartilage constructs to be further explored. The ability to cultivate engineered cartilage that can achieve native mechanical properties using adult chondrocytes is clinically significant.…”

Tendon Fascicles Exhibit a Linear Correlation Between Poisson's Ratio and Force During Uniaxial Stress Relaxation

“…These results agree with predictions from biphasic theory and suggest some or all of the apparent viscoelastic response may be explained by flow-dependent mechanisms. This result is highly relevant, as fluid movement has been implicated in nutrient transport and mechanotransduction and may be fundamentally important in the behavior of fascicles in normal tissues [6,9,26,27].…”

Agarose Hydrogel Characterization for Regenerative Medicine Applications: Focus on Engineering Cartilage

“…Dynamic compressive loading, a biomimetic approach, has been shown to enhance the active transport of large solutes in agarose gels [22][23][24], improving solute diffusion by ∼50% compared with statically loaded gels [22]. These results have been validated using techniques such as fluorescent molecule absorption/desorption and fluorescent recovery after photobleaching (FRAP) and have been shown to agree with solute modeling [23], Fickian diffusion theory [22], and mixture theory [24,25]. Under these applied cyclic strains, large chemical factors, such as IGF-1 (8 kDa) or TGF-β1 (25 kDa), can easily diffuse into an agarose scaffold.…”