Percorrer por autor "Carvalho, Filomena A."
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- Using plasma-mediated covalent functionalization of rhamnolipids on polydimethylsiloxane towards the antimicrobial improvement of catheter surfacesPublication . Dardouri, Maïssa; Bettencourt, Ana; Martin, Victor; Carvalho, Filomena A.; Santos, CatarinaControlling bacterial biofilm formation on silicone-based bloodstream catheters is of great concern to prevent relatedinfections. Inthis study, rhamnolipids(RLs),glycolipid biosurfactants,specifically a RLs mixture andthepurifieddi-RL (RhaRhaC10:0C10:0) were covalently bonded to silicone with the intention of reaching long-lasting antibiofilm surfaces. RLs mixture and di-RL wereidentified by an UHPLC-MSmethodthat also allowed the confirmation of compound isolation by automated flash chromatography. Silicone surfaces underwent air-plasma treatment, inducing reactive oxygenradicals able to promote theRLs grafting that was confirmed by contactangle,FTIR-ATR andAFMmeasurements. The antibiofilm activity towards different Gram positive strains was evaluated by colony forming units (CFU) count and confocal laser microscopy. In addition, protein adsorption and biocompatibility were also investigated. RLs were successfully grafted onto silicone and RLs mixture and RhaRhaC10C10:0 functionalized specimens reduced the biofilm formation over 2.3 log units against methicillin sensitive Staphylococcus aureus. Additionally, a decrease of 1 log unit was observed against methicillin resistant S. aureus and S. epidermidis. Functionalized samples showed cytocompatibility towards human dermal fibroblasts, hemocompatibility and no vascular irritation potential. The results mentioned above revealed a synergy between the antimicrobial and the anti-adhesive properties of RLs, making these compounds good candidates for the improvement of the medical devices antibiofilm properties.