Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Biofunctionalization of cellulosic fibres with l-cysteine: Assessment of antibacterial properties and mechanism of action against Staphylococcus aureus and Klebsiella pneumoniaePublication . Caldeira, Estela; Piskin, Erhan; Granadeiro, Luiza Breitenfeld ; Silva, Filomena; Gouveia, Isabel C.The main purpose of this work is to obtain a cotton-based textile material functionalized with l-cysteine (l-cys) to achieve an antimicrobial effect with potential application in biomedical, geriatric or pediatric textiles. The binding capacity of l-cys to cotton fibres was assessed through different functionalization strategies—surface activation and exhaustion processes. A subsequent analysis of the possible antibacterial action against Staphylococcus aureus and Klebsiella pneumoniae was performed according with the Japanese International standard (JISL, 2008). To determine the mechanism of action of l-cys on the selected strains, flow cytometry was used. The results revealed that the exhaustion process was performed with success to confer bioactivity to the treated fabric, as assessed by an effective antibacterial effect against both Gram-positive and Gram-negative bacteria, and successfully linkage of l-cys was observed via FTIR with a durable effect demonstrated after the washing tests (fastness to washing). It was also observed that l-cys exerts a bacteriostatic effect against both bacterial strains, since there were alterations in the metabolic activity ofthe microorganisms after the application of the bioactive textile which was shown by the CTC (cyanoditolyl tetrazolium chloride) staining used in flow cytometry. This study shows a new and successful biotechnological process to develop antibacterial textiles through the functionalization of cotton fibres with l-cys which presents a broad range of applications in healthcare, since l-cys is a natural antibacterial compound, non-toxic and affects pathogenic bacteria related to hospital infections.
- Antimicrobial and antioxidant surface modification toward a new silk-fibroin (SF)-l-Cysteine material for skin disease managementPublication . Nogueira, Frederico; Granadeiro, Luiza Breitenfeld ; Mouro, Cláudia; Gouveia, Isabel C.A novel dressing material – silk fibroin fabric (SF)-l-Cysteine (l-Cys) – is here developed to be used asstandard treatment for atopic dermatitis (AD), which combines comfort, thermic, and tensile strengthproperties of silk materials with antioxidant and antimicrobial effects of l-Cys. A careful understand-ing about the linking strategies is needed in order not to compromise the bioavailability of l-Cys anddeplenish its bioactivity. Durability was also addressed through washing cycles and compared with hos-pital requirements, according to international Standard EN ISO 105-C06:2010. The present research alsoanalyze the interactions between Staphylococcus aureus and SF-l-Cys under simulating conditions of ADand demonstrated the effectiveness of a double covalent grafting, with the importance of SF tyrosine(Tyr) covalent linkage with l-Cys (SF-g-l-Cys/Tyr-g-l-Cys) even after several washing cycles, twenty five,whereas for a disposable application a single covalent mechanism of grafting l-Cys proved to be suffi-cient (SF-g-l-Cys). Results showed effective antimicrobial activities exhibiting higher inhibition ratios of98.65% for SF-g-l-Cys after 5 washing cycles, whereas 97.55% for SF-g-l-Cys/Tyr-g-l-Cys after 25 washingcycles, both at pH 9.5 grafting strategy. Furthermore, it is also reported a non-protumoral effect of l-Cys. Anew advance is herein achieved at the world of medical antimicrobial textiles tailored to address woundmoisture environment and exudate self-cleaning, which may open novel applications as complementarytherapy for AD disease.