Browsing by Author "Costa, Raphael C."

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    Bacterial-derived extracellular polysaccharides reduce antimicrobial susceptibility on biotic and abiotic surfaces
    (2022) Souza, Joao Gabriel S.; Oliveira, Barbara E. Costa; Costa, Raphael C.; Bechara, Karen; Cardoso-Filho, Otavio; Benso, Bruna; Shibli, Jamil Awad; Bertolini, Martinna; Barao, Valentim A. R.
    Objective: Extracellular biofilm matrix plays a role in reducing bacterial susceptibility against antimicrobials. Since the surface where biofilm is growing modulates microbial accumulation and bacterial-derived exopoly-saccharides (EPS) synthesis, this study compared the role of EPS to reduce antimicrobial susceptibility on biotic (dental surface) and abiotic (titanium (Ti) material) surfaces and the effect of remaining matrix-enriched biofilms to promote bacterial recolonization. Design: 48 h Streptococcus mutans UA159 strain biofilms were grown on enamel and Ti surfaces. The medium was supplemented with 1% sucrose, substrate for EPS synthesis, or with 0.5% glucose + 0.5% fructose as control. Chlorhexidine (CHX) 0.2% was used for antimicrobial treatment. Biofilms were collected and the following analyses were considered: viable bacterial counts, biofilm pH, EPS content, and biofilm structure by scanning electron microscopy and confocal laser scanning microscopy (CLSM). Substrate surfaces were analyzed by 3D laser scanning confocal microscope. Results: Enamel surface showed a higher amount of EPS content (p < 0.05), which may be explained by the higher bacterial biomass compared to Ti material. EPS content reduced bacterial susceptibility against antimi-crobial treatments for both substrates, compared to EPS control (p < 0.05). However, sucrose-treated cells presented the same magnitude of reduction for Ti or enamel. Interestingly, matrix-enriched biofilms favored bacterial recolonization for both substrates. Conclusion: The surface where the biofilm is growing modulates the amount of EPS synthesized and matrix content plays a key role in reducing antimicrobial susceptibility and promoting bacterial recolonization.
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    Pathogenesis-Guided Engineering: pH-Responsive Imprinted Polymer Co-Delivering Folate for Inflammation-Resolving as Immunotherapy in Implant-Related Infections
    (2024) Costa, Raphael C.; Nagay, Bruna E.; Villa, Javier E. L.; Sotomayor, Maria D. P. T.; Neres, Lariel Chagas da Silva; Benso, Bruna; Aguayo, Sebastian; Sacramento, Catarina M.; Ruiz, Karina G. S.; Spada, Fernanda P.; de Avila, Erica Dorigatti; da Costa, Monique G.; Faverani, Leonardo P.; Cintra, Luciano T. A.; Souza, Joao Gabriel S.; Barao, Valentim A. R.
    Folate (FT) is a suitable targeting ligand for folate receptors (FOLR) overexpressed on inflamed cells. Thus, FT-loaded polymers can be used as FOLRs-targeted immunotherapy to positively modulate the inflammatory process. A novel biodegradable imprinted polymer with a FT delivery mechanism driven by pH changes [PCL-MIP@FT] is designed with molecularly imprinted technology. The pH mechanism is validated in vitro, demonstrating that an acidic environment accelerated and increased the release of FT for a period of 7 days (similar to 100 mu g mL-1). For the first time, FT receptors (FOLR-1 and FOLR-3) are discovered and also overexpressed on activated human gingival fibroblasts, representing a favorable target in the oral environment. Although FT itself does not have antimicrobial effects, the nanomechanical properties of biofilm are changed after topical FT administration. In vivo systemic toxicity of PCL-MIP@FT has been demonstrated to be a safe biomaterial (up to 1.3 mg kg-1). When the PCL-MIP@FT is assessed in the subcutaneous tissue, it promoted an alleviating inflammation and may be able to stimulate tissue repair. The present findings have demonstrated the reliable in vitro and in vivo anti-inflammatory actions of FT-loaded polymer and support its use as a novel drug-free therapeutic platform for modulating and mitigating inflammatory responses in dental implant-related infections.