Offeddu G S, Axpe E, Harley B A C, Oyen M L
The Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, United Kingdom.
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 110 Roger Adams Lab., 600 S. Mathews Avenue, Urbana, Illinois 61801, United States.
AIP Adv. 2018 Oct 4;8(10):105006. doi: 10.1063/1.5036999. eCollection 2018 Oct.
The transport properties of hydrogels largely affect their performance in biomedical applications ranging from cell culture scaffolds to drug delivery systems. Solutes can move through the polymer mesh as a result of concentration gradients in the interstitial fluid or pressure gradients that move the fluid and solutes simultaneously. The relationship between the two modalities of transport in hydrogels can provide insight for the design of materials that can function effectively in the dynamic conditions experienced and , yet this correlation has not been previously elucidated. Here, fluorescence recovery after photobleaching (FRAP) is used to measure the diffusivity of dextran molecules of different size within polyethylene glycol hydrogels. Spherical indentation analyzed in a poroelastic framework is used to measure the permeability to fluid flow of the same hydrogels. It is found that while the diffusivity varies with exp( ), where is the mesh size of the hydrogels, it also varies with exp( ), where is the intrinsic permeability. For the same hydrogel structure, diffusive transport is affected by the solute size, while convective transport is unaffected. As spherical indentation is a reliable, quick and non-destructive testing method for hydrated soft materials, the relationship provides the means to faster assessment of the transport properties of hydrogels and, ultimately, of their effective use in biomedical applications.
水凝胶的传输特性在很大程度上影响其在生物医学应用中的性能，这些应用涵盖从细胞培养支架到药物递送系统等领域。由于间质液中的浓度梯度或同时移动流体和溶质的压力梯度，溶质能够穿过聚合物网络。水凝胶中这两种传输方式之间的关系可为设计能在经历的动态条件下有效发挥作用的材料提供见解，然而这种相关性此前尚未得到阐明。在此，光漂白后荧光恢复（FRAP）用于测量不同大小的葡聚糖分子在聚乙二醇水凝胶中的扩散率。在多孔弹性框架中分析的球形压痕用于测量相同水凝胶对流体流动的渗透率。结果发现，虽然扩散率随exp( )变化，其中 是水凝胶的网孔尺寸，但它也随exp( )变化，其中 是固有渗透率。对于相同的水凝胶结构，扩散传输受溶质大小影响，而对流传输不受影响。由于球形压痕是一种用于含水软材料的可靠、快速且无损的测试方法，这种关系为更快评估水凝胶的传输特性以及最终评估其在生物医学应用中的有效利用提供了手段。
