(135f) Self-Assembly of Biofilm Amyloids and Graphene Quantum Dots Under Shear Forces

The biofilm, composed of microbial communities adherent to a surface, involves multiple problems in nature, industry, and human health. As the protective outer layer of biofilm, extracellular matrix (ECM), plays a key role on its resistance to environmental stress and antibiotics. In previous studies, graphene quantum dots have been demonstrated the ability to disperse the amyloid-rich biofilm by impeding the formation of amyloid fibers, a critical structure to promote the maturation of ECM, from α-helix amphipathic peptide monomer phenol soluble modulins. Here, we first study bacterial functional amyloid in Staphylococcus aureus biofilms fibrillation under shear forces, which is a key factor in environmental stress and physiological condition. And we also investigate how graphene quantum dots are able to manipulate the self-assembly of amyloid proteins which are sensitive to the flow stress in physiological conditions such as the brain or blood circulation under different shear forces. Using transmission electron microscopy, circular dichroism spectrometry, thioflavin fluorescence along with dynamic light scattering, we found the shear force speeds up the formation of amyloid fibers by changing the secondary structure of phenol soluble modulins. Graphene quantum dots can interfere with amyloid fibers formation via self-assembly with monomeric amyloid-like peptides with the existence of shear stress, which provides a potential anti-biofilm agent under the condition of shear force.