Salt-triggered peptide folding and consequent self-assembly into hydrogels with tunable modulus
Salt-triggered peptide folding and consequent self-assembly into hydrogels with tunable modulus
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DOI：
10.1021/ma0491762
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发表时间：
2004-09-21
期刊：
影响因子：
5.5
通讯作者：
Pochan, DJ
中科院分区：
文献类型：
--
作者：
Ozbas, B;Kretsinger, J;Pochan, DJ
由盐的存在触发的分子内折叠事件诱导β-发夹肽在生理条件下自组装成水凝胶网络。在pH 7.4和低离子强度溶液条件下，肽的稀释均匀溶液（小于或等于2wt%）表现出纯水的粘度。圆二色性光谱显示，在pH 7.4的盐的情况下，肽是未折叠的。通过提高溶液的离子强度，肽内带电氨基酸之间的静电相互作用被屏蔽，并采用β-发夹构象。折叠的β-发夹分子通过疏水塌陷和氢键超分子组装成三维水凝胶网络。FTIR和X射线散射数据表明，这些水凝胶富含β-折叠。动态振荡流变学测量表明，所得的超分子结构形成弹性材料，其结构，从而模量，可以通过盐浓度和温度进行调节。水凝胶的储能模量随着盐浓度的增加而增加。在生理条件下的细胞生长培养基中也观察到稳健的水凝胶化。透射电子显微镜显示，水凝胶的弹性来自于由半柔性纤维状组装体组成的网络纳米结构。
Intramolecular folding events, triggered by the presence of salt, induce the self-assembly of beta-hairpin peptides into hydrogel networks at physiological conditions. At pH 7.4 and low ionic strength solution conditions, dilute, homogeneous solutions of peptide (less than or equal to 2 wt %) exhibit the viscosity of pure water. Circular dichroism spectroscopy shows that, at pH 7.4 in the absence of salt, peptides are unfolded. By raising the ionic strength of the solution, electrostatic interactions between charged amino acids within the peptide are screened, and a beta-hairpin conformation is adopted. Folded beta-hairpin molecules supramolecularly assemble via hydrophobic collapse and hydrogen bonding into a three-dimensional hydrogel network. FTIR and X-ray scattering data demonstrate that these hydrogels are rich in beta-sheet. Dynamic oscillatory rheological measurements demonstrate that the resultant supramolecular structure forms an elastic material whose structure, and thus modulus, can be tuned by salt concentration and temperature. Storage moduli of hydrogels increase with increasing salt concentration. Robust hydrogelation is also observed in cell growth media at physiological conditions. Transmission electron microscopy reveals that the hydrogel elasticity arises from a network nanostructure consisting of semiflexible fibrillar assemblies.