Navegando por Autor "Dinescu, Gheorghe"
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Artigo Antimicrobial efficacy of low concentration PVP-silver nanoparticles deposited on DBD Plasma-Treated polyamide 6,6 fabric(Coatings, 2020-04-10) Silva, Késia Karina de Oliveira Souto; Ribeiro, Ana Isabel; Senturk, Dilara; Modic, Martina; Cvelbar, Uros; Dinescu, Gheorghe; Mitu, Bogdana; Nikiforov, Anton; Leys, Christophe; Kuchakova, Irina; Vrieze, Mike de; Souto, António Pedro; Zille, AndreaIn this study, a low concentration (10 μg·mL−1) of poly(N-vinylpyrrolidone) (PVP)-coated silver nanoparticles (AgNPs) were deposited by spray and exhaustion (30, 70 and 100 ◦C) methods onto untreated and dielectric barrier discharge (DBD) plasma-treated polyamide 6,6 (PA66) fabric. DBD plasma-treated samples showed higher AgNP deposition than untreated ones for all methods. After five washing cycles, only DBD plasma-treated samples displayed AgNPs on the fabric surface. The best-performing method was exhaustion at 30 ◦C, which exhibited less agglomeration and the best antibacterial efficacy against S. aureus (4 log reduction). For E. coli, the antimicrobial effect showed good results in all the exhaustion samples (5 log reduction). Considering the spray method, only the DBD plasma-treated samples showed some bacteriostatic activity for both strains, but the AgNP concentration was not enough to have a bactericidal effect. Our results suggest DBD plasma maybe a low cost and chemical-free method for the preparation of antibacterial textiles, allowing for the immobilization of a very low—but effective—concentration of AgNPsArtigo Efficient silver nanoparticles deposition method on DBD plasma-treated polyamide 6,6 for antimicrobial textiles(IOP Publishing, 2021-04-10) Silva, Késia Karina de Oliveira Souto; Ribeiro, Ana Isabel; Senturk, Dilara; Modic, Martina; Cvelbar, Uros; Dinescu, Gheorghe; Mitu, Bogdana; Nikiforov, Anton; Leys, Christophe; Kuchakova, Irina; Vanneste, M.; Heyse, P.; Vrieze, Mike de; Souto, António P.; Zille, AndreaSeveral methods for silver nanoparticles (AgNPs) deposition on dielectric barrier discharge (DBD) plasma treated and not treated polyamide 6,6 fabric were tested for the production of durable antibacterial textiles. Ultrasound-assisted, dip-coating, exhaustion at 70 ̊C and spray deposition methods were applied. The treated fabrics were analysed in terms of coating uniformity, plasma effect, nanoparticles concentration onto the fabrics and nanoparticles release. Scanning electron microscope (SEM), energy dispersive X-ray (EDX), atomic absorption spectroscopy (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES) and reflectance spectroscopy(%R) were performed. In the fabrics impregnated with AgNPs by dip coating or spray methods there are no significant differences in the plasma treated and untreated samples. Ultrasound tip and exhaustion at 70 ̊C presented higher AgNPs loading. Better AgNPs distribution, higher concentration and less agglomeration were observed in the plasma treated samples and an improved controlled release as well. The plasma treated fabrics with AgNPs deposited with the ultrasound method showed the highest concentration of nanoparticles onto the fabrics as well as the lowest NPs agglomeration. However, this deposition is limited to certain areas of the fabric, the samples were not uniform. The exhaustion method showed the best equilibrium between the NPs distribution and state of agglomeration