Direct Validation of Active Solute Transport Induced by Dynamic Loading of Porous Hydrated Media

Transport pathways play a key role in maintaining cellular metabolic activity in biological tissues. Efforts to maintain or enhance the transport of nutrients may prove beneficial to the maintenance of native or development of engineered tissue. Various studies have investigated the potential of dynamic mechanical loading to increase the uptake and desorption rates of solutes in articular cartilage [1, 2]. Recently, a novel concept has been theoretically suggested that such dynamic loading of porous deformable media may additionally yield higher steady state concentrations of solutes, beyond those achieved by passive diffusion [3]. The first experimental evidence that dynamic loading can significantly enhance solute uptake over passive diffusion was recently reported for a model system of dextran in agarose hydrogels [4]. The results of this experimental study [4] were interpreted in the context of the earlier theoretical predictions [3], though a direct validation of theory with experiments has not yet been attempted. Therefore, the current study focuses on directly validating the theoretical framework by independently measuring the mechanical and transport properties of agarose hydrogels and dextran solutions experimentally, and substituting these values into the theory to evaluate the predicted solute uptake. These predictions are then compared to the previously reported experimental measurements of uptake of dextran in agarose under dynamic loading [4], for several gel concentrations and solute molecular weights.