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EN
To decrease friction factor and enhance the biocompatibility of medical devices manufactured from poly(vinyl chloride), PVC, the surface modification with wear resistant polyurethane/polyvinylpyrrolidone (PUR/PVP) hydrogel coating can be applied. In the present work substrates were dip-coated with PVP and PUR solutions and thermally cured. The variable process parameters were: solvent system; concentration of polymers (1, 2 or 3% w/v); coating baths temperature (22, 38 and 55°C); drying temperature (32, 50 and 67°C); length of break between process steps (5, 30 and 90 s); and solutions storage time (up to 72 hrs). The quality of coatings was determined by friction coefficients against porcine aorta, weights of the deposited layer and the swelling capacity. The solvent system and polymers concentration were crucial factors. The increased temperature of coating solutions caused increased deposition but decreased durability. The most lubricious samples were dried in 50°C. Coatings from the solutions prepared 24h prior to use had better properties than those from fresh solutions.
EN
Polyvinylpyrrolidone (PVP) is employed in several potential applications, relying of its special chemical and physical properties in addition to its low toxicity and biocompatibility. The aim of this work is to prepare polyvinylpyrrolidone-silver (PVP-Ag) nanocomposite with high inhibiting effect on the microbial growth and low cytotoxicity. In situ prepared small stable spherical silver nanoparticles, with narrow range particle size distribution, were obtained by easy, economical and rapid chemical reduction method. Silver ions were reduced to silver nanoparticles using low amount of sodium borohydride (NaBH₄) as a strong reducing agent. PVP-Ag nanocomposite was prepared using PVP as a stabilizing and capping agent. Formation of the spherical silver nanoparticles with mean particle size 5 nm was confirmed by ultraviolet-visible spectroscopy, high resolution transmission electron microscopy, and dynamic light scattering. The inhibiting growth effect of the nanocomposite toward Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Pseudomonas aeruginosa), and yeast fungus (Candida albicans) were studied. The cytotoxicity of the nanocomposite against BJ1 normal skin fibroblast cell line was tested. Results of this work presented perfect antimicrobial activity of the PVP-Ag nanocomposite towards bacteria and fungi with low cytotoxicity, which may lead to promising applications in skin wound healing.
EN
A synthetic polymer, polyvinylpyrrolidone (PVP - E 1201) primarily finds applications in the pharmaceutical and food industries due to its resistance and zero toxicity to organisms. After ingestion, the substance passes through the organism unchanged. Consequently, it enters the systems of municipal wastewater treatment plants (WWTP) without decomposing biologically during the waste treatment process, nor does it attach (through sorption) to particles of activated sludge to any significant extent, therefore, it passes through the system of a WWTP, which may cause the substance to accumulate in the natural environment. For this reason the paper investigates the potential to initiate aerobic biodegradation of PVP in the presence of activated sludge from a municipal wastewater treatment plant. The following agents were selected as the initiators of the biodegradation process - co-substrates: acrylamide, N-acethylphenylalanine and 1-methyl-2-pyrrolidone, a substance with a similar structure to PVP monomer. The biodegradability of PVP in the presence of co-substrates was evaluated on the basis of biological oxygen demand (BOD) as determined via a MicroOxymax O2/CO2/CH4 respirometer. The total substrate concentration in the suspension equaled 400 mg·dm-3, with the ratio between PVP and the cosubstrate being 1:1, while the concentration of the dry activated sludge was 500 mg·dm-3. Even though there was no occurrence of a significant increase in the biodegradation of PVP alone in the presence of a co-substrate, acrylamide appeared to be the most effective type of co-substrate. Nevertheless, a recorded decrease in the slope of biodegradation curves over time may indicate that a process of primary decomposition was underway, which involves the production of metabolites that inhibit activated sludge microorganisms. The resulting products are not identified at this stage of experimentation.
PL
Syntetyczny polimer, poliwinylopirolidon (PVP - E 1201), znajduje zastosowanie przede wszystkim w przemyśle farmaceutycznym i spożywczym ze względu na jego odporność i brak toksyczności dla organizmów. Po spożyciu substancja ta przechodzi przez organizm niezmieniona. W związku z tym, że w procesie przetwarzania odpadów w komunalnym systemie oczyszczalni ścieków (OŚ) polimer ten nie ulega rozkładowi biologicznemu ani nie jest znacząco sorbowany w osadzie czynnym, może on gromadzić się w środowisku naturalnym. Ze względu na istnienie tych problemów w artykule przedstawiono możliwości aerobowej inicjacji biodegradacji PVP w obecności osadu czynnego miejskiej oczyszczalni ścieków. Jako inicjatory procesu biodegradacji zostały wybrane następujące środki: kosubstraty, akryloamid, N-acetylofenyloalanina i 1-metylo-2-pirolidon, substancje o strukturze podobnej do monomeru PVP. Biodegradację PVP w obecności kosubstratów oceniano na podstawie biologicznego zapotrzebowania na tlen (BOD), określonego za pomocą respirometru MicroOxymax O2/CO2/CH4. Całkowite stężenie substratu w zawiesinie wynosiło 400 mg · dm-3 dla stosunku PVP i kosubstratu wynoszącego 1:1 oraz dla stężenia suchego osadu czynnego wynoszącego 500 mg · dm-3. Chociaż nawet w tym układzie nie stwierdzono wzrostu biodegradacji samego PVP w obecności kosubstratu, to sam akryloamid okazał się najbardziej efektywnym rodzajem podłoża. Niemniej jednak, zauważony spadek nachylenia krzywych biodegradacji w czasie może wskazywać, że zachodzi proces rozkładu pierwotnego, który wiąże się z produkcją metabolitów hamujących aktywowane mikroorganizmy osadu. Otrzymane produkty nie zostały zidentyfikowane na tym etapie badań.
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