Department of Chemical Engineering , University of Michigan , Ann Arbor , Michigan 48109 , United States.
Biointerfaces Institute , University of Michigan , Ann Arbor , Michigan 48109 , United States.
ACS Nano. 2019 Apr 23;13(4):4278-4289. doi: 10.1021/acsnano.8b09403. Epub 2019 Apr 4.
Bacterial biofilms represent an essential part of Earth's ecosystem that can cause multiple ecological, technological, and health problems. The environmental resilience and sophisticated organization of biofilms are enabled by the extracellular matrix that creates a protective network of biomolecules around the bacterial community. Current anti-biofilm agents can interfere with extracellular matrix production but, being based on small molecules, are degraded by bacteria and rapidly diffuse away from biofilms. Both factors severely reduce their efficacy, while their toxicity to higher organisms creates additional barriers to their practicality. In this paper, we report on the ability of graphene quantum dots to effectively disperse mature amyloid-rich Staphylococcus aureus biofilms, interfering with the self-assembly of amyloid fibers, a key structural component of the extracellular matrix. Mimicking peptide-binding biomolecules, graphene quantum dots form supramolecular complexes with phenol-soluble modulins, the peptide monomers of amyloid fibers. Experimental and computational results show that graphene quantum dots efficiently dock near the N-terminus of the peptide and change the secondary structure of phenol-soluble modulins, which disrupts their fibrillation and represents a strategy for mitigation of bacterial communities.
细菌生物膜是地球生态系统的重要组成部分，可导致多种生态、技术和健康问题。生物膜的环境弹性和复杂组织是由细胞外基质实现的，它在细菌群落周围形成了一个保护生物分子网络。目前的抗生物膜剂可以干扰细胞外基质的产生，但由于它们基于小分子，会被细菌降解并迅速从生物膜中扩散出去。这两个因素都严重降低了它们的效果，而它们对高等生物的毒性又给它们的实用性增加了额外的障碍。在本文中，我们报告了石墨烯量子点有效分散成熟的富含淀粉样蛋白的金黄色葡萄球菌生物膜的能力，干扰了细胞外基质的关键结构成分——淀粉样纤维的自组装。石墨烯量子点模拟肽结合生物分子，与淀粉样纤维的肽单体酚可溶性调节素形成超分子复合物。实验和计算结果表明，石墨烯量子点有效地在肽的 N 端附近对接，并改变酚可溶性调节素的二级结构，这破坏了它们的纤化，代表了一种减轻细菌群落的策略。
