(159ba) Anti-biofilm Activity of Chiral Graphene Quantum Dots and Their Effects on Functional Bacterial Amyloid Proteins

The ability of bacteria to form complex structures called biofilms create numerous human health and industrial problems. These 3D architectures are defined by the extracellular polymer substance (EPS) that consists of a protective assembly of biomolecules surrounding encased planktonic bacterial cells. The current strategies for targeting biofilms weaken the EPS layer but are typically organic in nature and are subject to enzymatic degradation. Nanoparticles are a promising new class of anti-biofilm agents for their highly tunable physical and chemical properties, stability, and ability to interact with biological molecules, namely proteins. Here, we report the anti-biofilm activity of l-cysteine or d-cysteine derived chiral graphene quantum dots (L/D-GQDs) against amyloid rich staphylococcus aureus (S. aureus) biofilms. Both enantiomers are capable of biofilm disruption. Notably, D-GQDs displayed higher affinity for amyloid fibers causing increased biofilm dispersal compared to L-GQDs. Chiral GQDs mimic peptide binding proteins, interfering with the self-assembly phenol soluble modulins(PSMs) , the monomeric form of amyloid fibers responsible for biofilm structuring and multiple other virulence factors. The effect of chiral GQDs on key PSM functions including cytolysis, neutrophil production, and anti-biofilm properties were also explored. The chiral interactions between GQDs and biofilm components give rise to a highly tunable anti-biofilm NP platform.