Ramachandran Sivakumar, Tseng Yiider, Yu Y Bruce
Department of Pharmaceutics and Pharmaceutical Chemistry and Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA.
Biomacromolecules. 2005 May-Jun;6(3):1316-21. doi: 10.1021/bm049284w.
A pair of mutually attractive but self-repulsive decapeptides, with alternating charged/neutral amino acid sequence patterns, was found to co-assemble into a viscoelastic material upon mixing at a low total peptide concentration of 0.25 wt %. Circular dichroism spectroscopy of individual decapeptide solutions revealed their random coil conformation. Transmission electron microscopy images showed the nanofibrillar network structure of the hydrogel. Dynamic rheological characterization revealed its high elasticity and shear-thinning nature. Furthermore, the co-assembled hydrogel was capable of rapid recoveries from repeated shear-induced breakdowns, a property desirable for designing injectable biomaterials for controlled drug delivery and tissue engineering applications. A systematic variation of the neutral amino acids in the sequence revealed some of the design principles for this class of biomaterials. First, viscoelastic properties of the hydrogels can be tuned through adjusting the hydrophobicity of the neutral amino acids. Second, the beta-sheet propensity of the neutral amino acid residue in the peptides is critical for hydrogelation.
发现一对相互吸引但自身排斥的十肽，其具有交替的带电/中性氨基酸序列模式，在总肽浓度低至0.25 wt% 的情况下混合时会共同组装成一种粘弹性材料。对单个十肽溶液的圆二色光谱分析表明它们具有无规卷曲构象。透射电子显微镜图像显示了水凝胶的纳米纤维网络结构。动态流变学表征揭示了其高弹性和剪切变稀特性。此外，共同组装的水凝胶能够从反复的剪切诱导破坏中快速恢复，这是设计用于可控药物递送和组织工程应用的可注射生物材料所需的特性。对序列中中性氨基酸的系统变化揭示了这类生物材料的一些设计原则。首先，可以通过调节中性氨基酸的疏水性来调整水凝胶的粘弹性。其次，肽中中性氨基酸残基的β-折叠倾向对于水凝胶化至关重要。
