Pakstis Lisa M, Ozbas Bulent, Hales Kelly D, Nowak Andrew P, Deming Timothy J, Pochan Darrin
Department of Materials Science, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19716, USA.
Biomacromolecules. 2004 Mar-Apr;5(2):312-8. doi: 10.1021/bm034249v.
Amphiphilic, diblock copolypeptides of hydrophilic lysine or glutamic acid and hydrophobic leucine or valine have been observed to self-assemble into rigid hydrogels in aqueous solution at neutral pH and very low volume fraction of polymer, > or =0.5 wt % polypeptide. Laser scanning confocal microscopy and ultra small angle neutron scattering revealed a heterogeneous microstructure with distinct domains of hydrogel matrix and pure water pores. In situ nanoscale characterization, using cryogenic transmission electron microscopy, revealed a porous, interconnected membranous network of assembled polypeptides. At concentrations of polypeptide below gelation, diblocks containing lysine were cytotoxic to cells, whereas those containing glutamic acid were noncytotoxic. At higher polypeptide concentrations, within rigid gel scaffolds, both lysine and glutamic acid based diblocks were noncytotoxic but did not support cell attachment/proliferation. The cationic chemistry observed as cytotoxic in the fluid state was essentially inert in the intact, rigid hydrogel state.
由亲水性赖氨酸或谷氨酸以及疏水性亮氨酸或缬氨酸组成的两亲性二嵌段共多肽，已被观察到在中性pH值和极低聚合物体积分数（≥0.5 wt%多肽）的水溶液中自组装成刚性水凝胶。激光扫描共聚焦显微镜和超小角中子散射显示出一种异质微观结构，具有明显的水凝胶基质域和纯水孔。使用低温透射电子显微镜进行的原位纳米级表征揭示了组装多肽的多孔、相互连接的膜状网络。在低于凝胶化的多肽浓度下，含赖氨酸的二嵌段对细胞具有细胞毒性，而含谷氨酸的二嵌段则无细胞毒性。在较高的多肽浓度下，在刚性凝胶支架内，基于赖氨酸和谷氨酸的二嵌段均无细胞毒性，但不支持细胞附着/增殖。在流体状态下观察到具有细胞毒性的阳离子化学性质在完整的刚性水凝胶状态下基本呈惰性。
