Specific Antibiofilm of Carbon Quantum Dots by Destroying P. gingivalis Biofilm Related Proteins Self-assembly

Abstract Biofilms protected bacteria from antibiotics and produced drug-resistant strains, especially the main pathogen of periodontitis- Porphyromonas gingivalis ( P. gingivalis ). In this investigation, the carbon quantum dots (TCDs and MCDs) were prepared by hydrothermal method with clinic antibacterial drug-Tinidazole and Metronidazole and exhibited unique antibiofilm properties. The transmission electron microscope (TEM) images showed that the TCDs and MCDs had uniform sizes and the results of UV-vis and energy dispersive spectrometer (EDS) confirmed their important carbon polymerization structures. The prepared TCDs and MCDs were characterized by infrared spectroscopy and still kept the activity of nitro group, which still had an obvious effect on P. gingivalis . Interestingly, the results showed that they both have significant antibacterial effect on P. gingivalis , while the effect of TCDs was better than MCDs. However the TCDs has almost ineffect on other bacteria including Escherichia coli ( E. coli ), Staphylococcus aureus ( S. aureus ) and Prevotella nigrescens ( P. nigrescens ), the MCDs still have obviously antibacterial ability to P. ningrescens . Importantly, the TCDs can penetrate the biofilms to further effectively inhibited the growth of P. gingivalis under the biofilms. Furtherly, we revealed the hydrophilic TCDs destroy P. gingivalis ’ adhesion and impair toxicity by inhibiting the major virulence factors and related genes involved in biofilm formation of P. gingivalis, thus affect the self-assembly of biofilm related proteins. The findings may not only develop a new promising method for improve the periodontitis treatment efficiency by penetrating P. gingivalis biofilm with preparation of nano-level antibacterial drugs.