Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
Biopolymers. 2012 Mar;97(3):177-88. doi: 10.1002/bip.21722. Epub 2011 Oct 12.
Biocompatible and biodegradable peptide hydrogels are drawing increasing attention as prospective materials for human soft tissue repair and replacement. To improve the rather unfavorable mechanical properties of our pure peptide hydrogels, in this work we examined the possibility of creating a double hydrogel network. This network was created by means of the coassembly of mutually attractive, but self-repulsive oligopeptides within an already-existing fibrous network formed by the charged, biocompatible polysaccharides chitosan, alginate, and chondroitin. Using dynamic oscillatory rheology experiments, it was found that the coassembly of the peptides within the existing polysaccharide network resulted in a less stiff material as compared to the pure peptide networks (the elastic modulus G' decreased from 90 to 10 kPa). However, these composite oligopeptide-polysaccharide hydrogels were characterized by a greater resistance to deformation (the yield strain γ grew from 4 to 100%). Small-angle neutron scattering (SANS) was used to study the 2D cross-sectional shapes of the fibers, their dimensional characteristics, and the mesh sizes of the fibrous networks. Differences in material structures found with SANS experiments confirmed rheology data, showing that incorporation of the peptides dramatically changed the morphology of the polysaccharide network. The resulting fibers were structurally very similar to those forming the pure peptide networks, but formed less stiff gels because of their markedly greater mesh sizes. Together, these findings suggest an approach for the development of highly deformation-resistant biomaterials.
生物相容和可生物降解的肽水凝胶作为人类软组织修复和替代的潜在材料越来越受到关注。为了改善我们纯肽水凝胶相当不理想的机械性能，在这项工作中，我们研究了创建双水凝胶网络的可能性。该网络是通过在已存在的纤维网络中共同组装相互吸引但自排斥的短肽而形成的，该纤维网络由带电荷的、生物相容的多糖壳聚糖、藻酸盐和软骨素形成。使用动态振荡流变学实验发现，与纯肽网络相比，在现有的多糖网络中共同组装肽导致材料的硬度降低（弹性模量 G'从 90kPa 降低到 10kPa）。然而，这些复合的短肽-多糖水凝胶的特点是具有更大的抗变形能力（屈服应变γ从 4%增加到 100%）。小角中子散射（SANS）用于研究纤维的 2D 横截面形状、它们的尺寸特征和纤维网络的网格尺寸。SANS 实验中发现的材料结构差异证实了流变学数据，表明短肽的掺入显著改变了多糖网络的形态。所得纤维在结构上与形成纯肽网络的纤维非常相似，但由于其明显更大的网格尺寸，形成的凝胶硬度较低。总之，这些发现为开发高抗变形的生物材料提供了一种方法。
