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

Most microorganisms survive in the form of biofilms -structurally and functionally sophisticated microbial communities. Biofilms are implicated in numerous technological problems from water membrane failures to airplane crashes 1,2 as well as in various diseases from persistent infections to cancer 3, 4 . Biofilms also form a large component of the ecosphere on Earth and their dysregulation can also cause significant ecological consequences. 5 Biofilms act like multicellular organisms and possess exceptional adaptability and resilience to environmental factors and pharmaceuticals. 6, 7 Both of these properties are afforded by the protective function of extracellular matrix (ECM), which is made from several types of biomolecules (i.e., polysaccharides, DNA, and peptides). 8, 9 To date only a few classes of compounds have been shown to be effective anti-biofilm agents. 10, 11 Peptides rich in amino acids such as proline, arginine, phenylalanine or tryptophan have shown broad-spectrum activity in killing bacteria within biofilms by targeting a universal stringent stress response in bacteria. 12 However, they are currently being developed only as antibiotic adjuvants because they are subject to rapid proteolytic degradation and are relatively expensive to synthesize. Small molecules have been used to inhibit the quorum sensing (QS) system 13 or interfere with the polymerization of amyloid proteins. 14 While further exploration of these strategies of biofilm inhibition need to be explored, the rapid loss of the small molecules due to diffusion into environment reduce their efficacy and increase their environmental toxicity.