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

Such interaction may change secondary structure of peptides incubated with GQDs, and/or enhance the CD signal of turns by GQD. Subsequently, the negative band at ≈ 218 nm of β-sheet was enhanced in PSMα1 self-assembling without GQDs after a nine-day incubation, which agrees with the significant increase in ThT fluorescence emission (Figure 4b, S4 ). The change of CD peak in PSMα1 control from Day 4 to Day 9 indicated the transition from lag phase of individual peptides and oligomer to fibril formation 42 . Fibrillation of PSMα1 incubated with GQDs was inhibited when the molar ratio of peptides and GQDs are equal or more than 1:1 (GQD concentration at 200 μg/mL). However, the fibrillation CD signal of PSMα1 was further interrupted when incubated with excess amount of GQDs (800 μg/mL) on both Day 4 and 9 (Figure 4 a, b) .