Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA 01003-9303, USA.
Acta Biomater. 2011 Nov;7(11):3988-98. doi: 10.1016/j.actbio.2011.07.009. Epub 2011 Jul 14.
Obstructed transport of biological molecules can result in improper release of pharmaceuticals or biologics from biomedical devices. Recent studies have shown that nonionic surfactants, such as Pluronic® F68 (F68), positively alter biomaterial properties such as mesh size and microcapsule diameter. To further understand the effect of F68 (incorporated at concentrations well above the critical micelle concentration (CMC)) in traditional biomaterials, the transport properties of BSA and riboflavin were investigated in F68-alginate composite hydrogels, formed by both internal and external cross-linking with divalent cations. Results indicate that small molecule transport (represented by riboflavin) was not significantly hindered by F68 in homogeneously (internally) cross-linked hydrogels (up to an 11% decrease in loading capacity and 14% increase in effective diffusion coefficient, D(eff)), while protein transport in homogeneously cross-linked hydrogels (represented by BSA) was significantly affected (up to a 43% decrease in loading capacity and 40% increase in D(eff)). For inhomogeneously cross-linked hydrogels (externally cross-linked by CaCl(2) or BaCl(2)), the D(eff) increased up to 50 and 83% for small molecules and proteins, respectively. Variation in the alginate gelation method was shown to affect transport through measurable changes in swelling ratio (30% decrease) and observable changes in cross-linking structure as well as up to a 3.6- and 11.8-fold difference in D(eff) for riboflavin and BSA, respectively. Aside from the expected significant changes due to the cross-linking method utilized, protein transport properties were altered due to mesh size restrictions (10-25 nm estimated by mechanical properties) and BSA-F68 interaction (DLS). Taken as a whole, these results show that incorporation of a nonionic surfactant at concentrations above the CMC can affect device functionality by impeding the transport of large biological molecules.
生物分子的传输受阻可能导致生物医学设备中药物或生物制剂的释放不当。最近的研究表明，非离子表面活性剂，如泊洛沙姆 F68（F68），可以积极改变生物材料的性质，如网格大小和微胶囊直径。为了进一步了解 F68（浓度远高于临界胶束浓度（CMC））在传统生物材料中的影响，研究了 F68-海藻酸盐复合水凝胶中 BSA 和核黄素的传输性质，该水凝胶通过二价阳离子的内部和外部交联形成。结果表明，小分子传输（以核黄素表示）在均匀（内部）交联水凝胶中不受 F68 的显著阻碍（负载能力降低 11%，有效扩散系数 D(eff)增加 14%），而在均匀交联水凝胶中蛋白质传输（以 BSA 表示）受到显著影响（负载能力降低 43%，D(eff)增加 40%）。对于不均匀交联的水凝胶（由 CaCl2 或 BaCl2 外部交联），小分子和蛋白质的 D(eff)分别增加了 50%和 83%。海藻酸盐凝胶化方法的变化表明，通过可测量的溶胀比变化（降低 30%）和交联结构的可见变化以及 D(eff)分别高达 3.6 倍和 11.8 倍的变化，对传输产生影响核黄素和 BSA。除了由于交联方法的使用而导致的预期的重大变化外，蛋白质的传输特性还受到网格尺寸限制（通过机械性能估计为 10-25nm）和 BSA-F68 相互作用（DLS）的影响。总的来说，这些结果表明，在浓度高于 CMC 的情况下加入非离子表面活性剂会通过阻碍大分子生物分子的传输来影响设备的功能。
