Periodontitis is a chronic inflammatory disease driven by a dysbiotic, polymicrobial oral microbiome, forming multispecies 3D biofilms that promote microbial persistence, interspecies communication, and evasion of host defences. Bacteria within these biofilms release extracellular vesicles (EVs) containing proteins, nucleic acids, and virulence factors that modulate host immunity and enhance pathogenicity. Studying these polymicrobial 3D biofilms and microbial EVs is crucial for understanding disease mechanisms and identifying novel biomarkers.
Our team showed that polymicrobial oral biofilms on 3D melt electrowritten PCL scaffolds mimic saliva microbiome profiles, enriched with both commensals and pathogens, including Porphyromonas gingivalis, and Treponema denticola, alongside probiotics like Lactobacillus acidophilus. The proteomic data revealed a functionally dynamic biofilm ecosystem with elevated proteins in glycolysis, the TCA cycle, and nucleotide metabolism, highlighting pathways for biofilm survival, stress adaptation, and host interaction. MEW mPCL biofilms secreted significantly higher bacterial EVs from P. gingivalis, Eikenella corrodens, and L. acidophilus.
Additionally, healthy saliva biofilm OMVs enhanced the biomass and activity of saliva biofilms on titanium, inhibiting Porphyromonas gingivalis and Fusobacterium nucleatum while increasing Streptococcus mutans expression. OMVs also elevated IL-6 mRNA and protein in human oral epithelial cells, but suppressed IL-1α and MCP-1 24 hours post-incubation. In terms of periodontitis diagnosis, our team demonstrated that LPS+ OMVs were increased in periodontitis patients, along with significantly higher bacterial outer membrane vesicles (AUC>0.89) from Treponema, Fretibacterium, and Treponema denticola, compared to both healthy and gingivitis.
Together, these results underscore the dual importance of polymicrobial 3D biofilm models for mechanistic studies and microbial EVs as promising biomarkers and modulators in periodontal disease.