Li Bingyun, Rozas Joshua, Haynie Donald T
Bionanosystems Engineering Laboratory, Center for Applied Physics Studies, Biomedical Engineering and Physics, P.O. Box 10348, Louisiana Tech University, Ruston, Louisiana 71272, USA.
Biotechnol Prog. 2006 Jan-Feb;22(1):111-7. doi: 10.1021/bp050131+.
Self-assembly of designed peptides is a promising area of biomaterials research and development. Here, polypeptide nanofilms have been prepared by electrostatic layer-by-layer self-assembly (LBL) of cysteine (Cys)-containing 32mers designed to be oppositely charged at neutral pH, and structural stability of the films has been probed by subjecting them to various extreme physical and chemical conditions. The results suggest that although electrostatic attraction plays a key role in strengthening polypeptide films, stability is inversely related to absolute net charge of the supramolecular complex. This behavior is similar to the typical behavior of small globular proteins. Film structure is very stable in organic solvent and, when dehydrated, at extreme temperatures. Such stability is in marked contrast to the behavior of proteins, which tend to denature under comparable conditions. Similar to proteins, peptide nanofilms cross-linked by disulfide (S-S) bonds are considerably stronger than films stabilized by electrostatic, van der Waals, or hydrophobic interactions alone. This effect is particularly evident at extremes of pH and at elevated temperature when the film is hydrated. These results, the great variety of possible peptide structures, the inherent biocompatibility of l-amino acids, and current applications of thin films in commercial products together suggest that polypeptide films are promising for the development of new or enhanced products in food technology, drug delivery and medical device coatings, and biomaterials.
设计肽的自组装是生物材料研发中一个很有前景的领域。在此，通过对在中性pH下带相反电荷的含半胱氨酸（Cys）的32聚体进行静电逐层自组装（LBL）制备了多肽纳米薄膜，并通过使其经受各种极端物理和化学条件来探究薄膜的结构稳定性。结果表明，尽管静电引力在强化多肽薄膜中起关键作用，但稳定性与超分子复合物的绝对净电荷呈负相关。这种行为类似于小球蛋白的典型行为。薄膜结构在有机溶剂中以及脱水后在极端温度下非常稳定。这种稳定性与蛋白质在类似条件下倾向于变性的行为形成鲜明对比。与蛋白质类似，通过二硫键（S-S）交联的肽纳米薄膜比仅通过静电、范德华力或疏水相互作用稳定的薄膜要强得多。当薄膜水合时，这种效应在极端pH值和高温下尤为明显。这些结果、多种可能的肽结构、L-氨基酸固有的生物相容性以及薄膜在商业产品中的当前应用共同表明，多肽薄膜在食品技术、药物递送和医疗设备涂层以及生物材料等新的或改进产品的开发方面具有广阔前景。
