Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center , University of Oklahoma , Norman , Oklahoma 73019 , United States.
ACS Appl Mater Interfaces. 2019 Aug 14;11(32):28681-28689. doi: 10.1021/acsami.9b09583. Epub 2019 Aug 2.
One of the major hurdles in the development of antimicrobial peptide (AMP)-based materials is their poor capacity in selectively killing bacteria without harming nearby mammalian cells. Namely, they are antimicrobial but cytotoxic. Current methods of nanoparticle-encapsulated AMPs to target bacteria selectively still have not yet overcome this hurdle. Here, we demonstrate a simple yet effective method to address this daunting challenge by associating a natural AMP with a β-sheet-forming synthetic peptide. The integrated peptides self-assembled to form a supramolecular nanofiber, resulting in the presentation of the AMP at the nanofiber-solvent interface in a precisely controlled manner. Using melittin as a model natural AMP, we found that the conformation of melittin changed dramatically when presented on the nanofiber surface, which, in turn, modulated the induced membrane permeability of the bacterial and mammalian cell membranes. Specifically, the presentation of melittin on the nanofiber restricted its hydrophobic residues, leading to a reduction of the hydrophobic interaction with lipids in the cell membranes. Compellingly, the reduced hydrophobic interaction led to a considerable decrease of melittin's induced permeability of the mammalian cell membrane than that of the bacterial cell membrane. As a result, the AMP-displaying nanofiber preferentially permeabilized and disrupted the membrane of the bacteria without compromising the mammalian cells. Such improved membrane selectivity and cytocompatibility were confirmed in a cell-based membrane localization and live-dead assay. Our new strategy holds great promise for fabricating cytocompatible antimicrobial assemblies that offer safer and more effective administration of therapeutic AMPs. These assemblies, with intrinsic antimicrobial activity and cytocompatibility, can also serve as building blocks for the construction of higher-ordered scaffolds for other biomedical applications such as tissue engineering and regenerative medicine.
在开发基于抗菌肽 (AMP) 的材料时，一个主要的障碍是它们缺乏选择性地杀死细菌而不伤害附近哺乳动物细胞的能力。也就是说，它们具有抗菌性但同时具有细胞毒性。目前，使用纳米颗粒包裹 AMP 来选择性地靶向细菌的方法仍然没有克服这一障碍。在这里，我们展示了一种简单而有效的方法，通过将天然 AMP 与β-折叠合成肽结合来解决这一艰巨的挑战。整合的肽自组装形成超分子纳米纤维，从而以精确控制的方式将 AMP 呈现到纳米纤维-溶剂界面上。使用蜂毒素作为模型天然 AMP，我们发现当蜂毒素呈现于纳米纤维表面时，其构象发生了剧烈变化，这反过来又调节了细菌和哺乳动物细胞膜的诱导通透性。具体而言，蜂毒素在纳米纤维表面的呈现限制了其疏水性残基，导致与细胞膜中脂质的疏水性相互作用减少。引人注目的是，疏水性相互作用的减少导致蜂毒素对哺乳动物细胞膜的诱导通透性比细菌细胞膜的通透性显著降低。因此，展示 AMP 的纳米纤维优先渗透和破坏细菌的膜，而不会损害哺乳动物细胞。这种改善的膜选择性和细胞相容性在基于细胞的膜定位和死活测定中得到了证实。我们的新策略为制造细胞相容性的抗菌组装体提供了很大的希望，这些组装体具有内在的抗菌活性和细胞相容性，也可以作为构建更高阶支架的构建块，用于其他生物医学应用，如组织工程和再生医学。
