Anti-biofilm Activity of Graphene Quantum Dots via Self-Assembly with Bacterial Amyloid Proteins

Yichun Wang; Usha Kadiyala; Zhibei Qu; Paolo Elvati; Christopher Altheim; Nicholas A. Kotov; Angela Violi; J. Scott VanEpps

As an experimental model to study the anti-biofilm effects of GQDs, we used biofilms of Staphylococcus aureus --a major cause of hospital-and community-associated bacterial infections in the U.S. and around the world. 32 Formation of S. aureus biofilms on host tissues and implanted medical devices contributes to chronic infections, as biofilms are known to be exceptionally resistant to host immune response and tolerant to antibiotics. 36 The formation and dispersion of staphylococcal biofilms is dependent on the secretion of the phenol-soluble modulins (PSMs) [32] [33] [34] --small α-helical amphipathic peptides that have previously been implicated in bacterial virulence. 35, 36 Assembly of PSMs into fibers 35 promotes the maturation of ECM, 32,37,38 whose integrity renders these bacterial communities resistant to dispersal by proteinase K, Dispersin B, DNase and sodium dodecyl sulfate. 32 The self-assembly process of PSMs into amyloid-like fibers involves backbone hydrogen bonding and side-chain interaction (e.g., hydrophobic interaction, π-stacking, and van der Waals All rights reserved. No reuse allowed without permission.