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Start date: 2023Subject: search.filters.subject.antibacterial activity

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Now showing 1 - 3 of 3
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    PublicationOpen Access
    Biocompatibility vs antibacterial activity: chitosan-mediated nanosilver/PCL/gelatin nanofibers
    (Taylor and Francis Ltd., 2026) Chandraguptha, D; Fernando, L; Herath, L; Godakanda, V. U; Perera, N; Samarakoon, S; de Silva, K. M. N; Williams, G.R; de Silva, W. R.M
    Electrospinning is an efficient approach to prepare nanofiber scaffolds that mimic local tissue environments. While many reported scaffolds incorporate nanoparticles, detailed assessments of how nanosilver distribution affects antibacterial activity and biocompatibility remain limited. In this study, we developed an electrospun biopolymer scaffold composed of polycaprolactone and gelatin with chitosan-mediated nanosilver (C-AgNPs), introduced either by bulk surface coating or by dispersing the NPs within the electrospinning solution. The C-AgNP surface-coated scaffold exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas the dispersed scaffold did not. However, the dispersed scaffold promoted higher dermal fibroblast viability (82.7%) compared with the coated scaffold (60.9%). Zebrafish embryo assays further revealed mild developmental toxicity from the coated scaffold but no observable toxicity from the dispersed formulation. These findings demonstrate a distinct trade-off between antibacterial efficacy and cytocompatibility depending on nanoparticle distribution. Understanding this relationship is critical for designing electrospun nanofiber scaffolds with balanced biological properties.
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    PublicationOpen Access
    Persulfate assisted photocatalytic and antibacterial activity of TiO2–CuO coupled with graphene oxide and reduced graphene oxide
    (https://www.nature.com, 2024-05-31) Thambiliyagodage, C; Liyanaarachchi, H; Jayanetti, M; Ekanayake, G; Mendis, A; Samarakoon, U; Vigneswaran, S
    Photocatalysts of TiO2–CuO coupled with 30% graphene oxide (GO) were hydrothermally fabricated, which varied the TiO2 to CuO weight ratios to 1:4, 1:2, 1:1, 2:1 and 4:1 and reduced to form TiO2–CuO/reduced graphene oxide (rGO) photocatalysts. They were characterized using XRD, TEM, SEM, XPS, Raman, and DRS technologies. TiO2–CuO composites and TiO2–CuO/GO degrade methylene blue when persulfate ions are present. Persulfate concentration ranged from 1, 2, 4 to 8 mmol/dm−3 in which the highest activity of 4.4 × 10–2 and 7.35 × 10–2 min−1 was obtained with 4 mmol/dm−3 for TiO2–CuO (1:4) and TiO2–CuO/GO (1:1), respectively. The presence of EDTA and isopropyl alcohol reduced the photodegradation. TiO2–CuO coupled with rGO coagulates methylene blue in the presence of persulfate ions and such coagulation is independent of light. The catalyst dosage and the concentration of the dye were varied for the best-performing samples. The antibacterial activity of the synthesized samples was evaluated against the growth of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumonia. Ti:Cu (1:2)-GO and Ti:Cu (1:4)-GO had the highest antibacterial activity against K. pneumoniae (16.08 ± 0.14 mm), P. aeruginosa (22.33 ± 0.58 mm), E. coli (16.17 ± 0.29 mm) and S. aureus (16.08 ± 0.88).
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    PublicationOpen Access
    Evaluation of Antibacterial Activity of Rhinacanthus Species in Sri Lanka
    (Faculty of Humanities and Sciences, SLIIT, 2023-11-01) Somaratne, Y; Perera, M; Karunagoda, R
    Rhinacanthus nasutus (L.) Kurz is a valuable medicinal plant belonging to the family Acanthaceae that has many applications in the Ayurvedic system of medicine in Sri Lanka. Rhinacanthus polonnaruwensis Cramer is a more recently discovered species endemic to Sri Lanka, but its medicinal properties have not been recorded so far. The objective of the present study was to screen the antibacterial activity of leaf extracts of R. nasutus and R. polonnaruwensis against clinically isolated Gram-negative and Gram-positive bacteria. The study was carried out on six bacterial species, Escherichia coli, Staphylococcus aureus, S. saprophyticus, Pseudomonas aeruginosa, Salmonella typhi and Shigella flexi. Polar extracts of R. nasutus and R. polonnaruwensis were obtained by grinding the leaves with sterilized water and boiling the leaves in distilled water to obtain a decoction. A decoction of the concentration of 0.2 ml/ml of R. nasutus inhibited growth of all standard Gram-positive bacteria; Staphylococcus aureus and MRSA, whereas 0.2 ml/ml of decoction of R. polonnaruwensis inhibited growth of Staphylococcus aureus. Clinically isolated Staphylococcus saprophyticus was inhibited by both decoctions of Rhinacanthus species. None of the tested concentrations of the two Rhinacanthus species inhibited the growth of any Gram-negative bacteria; Pseudomonas aeruginosa, Escherichia coli, and Shigella flexi. In this study, we demonstrated that the leaf extracts of both R. nasutus and R. polonnaruwensis were effective at inhibiting Gram-positive bacteria. However, the decoction of R. nasutus was found to be more effective against the tested Grampositive bacteria than R. polonnaruwensis.