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

Circular dichroism (CD) spectrometry was used to obtain complementary information about the secondary structure of the amyloid fibrils. A wide negative peak between 200 nm to 230 nm observed in the CD spectrum (Figure 2d ) is characteristic of amyloid-like fibrils including typical β-sheet signals at negative at 218 nm and α-helix negative bands at 208 nm and 222 nm. The negative CD peak at ≈245 nm is associated with extracellular DNA. 41 All peaks between 200 nm to 250 nm were significantly decreased after two-hour incubation with GQDs suggesting that GQDs cause disruption of the fibril composite structure of extracted biofilm ECM within this timeframe.