Vermikulit s Ag a Cu použitý jako antibakteriální nanoplnivo v polyethylenu

Vermiculite (Ver) enriched with silver and copper was used as nanofiller to the polyethylene (PE) matrix. Specifically, the low density polyethylene (LDPE) was chosen as a matrix. The samples Ver-Ag,Cu were prepared by shaking of Ver with the aqueous solutions of silver and copper nitrate. The mixtures of the Ver nanofillers and PE were homogenized by melt compounding technique and further thin plates were pressed from stiff matter of PE with Ver nanofiller. The exfoliation of the powdery Ver nanofillers in PE matrix was characterized by the X-ray diffraction analysis of thin plates. Distribution of Ver nanofiller in PE matrix was observed by Light microscopy. The reinforcing effect of nanofillers onto PE matrix was studied by creep experiment. Antibacterial activity of powder Ver-Ag,Cu samples and surfaces of PE/Ver-Ag,Cu samples was tested on the Gram-positive bacteria Enterococcus faecalis. All tested PE/Ver-Ag,Cu surfaces showed good antibacterial behaviour after 24 h in comparison to pure PE. The number of colonies decreased from the countless number to several hundred colonies.Vermikulit (Ver) obohacený stříbrem a mědí byl použit jako nanoplnivo v polyethylenové (PE) matrici. Konkrétně byl jako matrice vybrán nízko hustotní polyethylen (LDPE). Vzorky Ver-Ag,Cu byly připraveny mícháním Ver s vodnými roztoky dusičnanu stříbrného a měďnatého. Směsi Ver nanoplniv a PE byly homogenizovány postupem míchání taveniny a následně byly ze ztuhnuté směsi PE s Ver nanoplnivem vylisovány tenké destičky. Exfoliace práškového Ver nanoplniva v PE matrici byla hodnocena pomocí Rentgenové difrakční analýzy tenkých destiček. Distribuce Ver nanoplniva v PE matrici byla studována Světelnou mikroskopií. Vyztužující efekt nanoplniv na PE matrici byl studován pomocí krípového experimentu. Antibakteriální působení práškových vzorků Ver-Ag,Cu a povrchů vzorků PE/Ver-Ag,Cu bylo testováno na grampozitivní bakterii Enterococcus faecalis. Všechny testované povrchy PE/Ver-Ag,Cu vykazovaly dobré antibakteriální působení po 24 h oproti povrchu čistého PE. Počet kolonií poklesl z nespočetného množství na několik stovek kolonií

Preparation of organoclays with antibacterial properties

Import 29/09/2010Metodou kationové výměny byly připraveny tři série monoionních forem jílových minerálů montmorillonitu a vermikulitu obsahující kationy Ag+, Zn2+ a Cu2+. Organojíly vykazující antibakteriální účinky byly připraveny interkalací chlorhexidin diacetátu s výše uvedenými monoionními jíly. Výsledné vzorky byly analyzovány pomocí rentgenové difrakce (RTG) a infračervené spektroskopie (IČE). Antibakteriální účinnost připravených organojílů byla testována proti kmenům Enterococus faecalis, Escherichia coli a Pseudomonas aeruginosa a byla vyhodnocena jako minimální inhibiční koncentrace (MIC). Bylo zjištěno, že připravené organovermikulity mají v porovnání s organomontmorillonity lepší schopnost inhibovat bakteriální růst a jsou tedy antibakteriálně účinnější.A three series of monoionic montmorillonites and vermiculites loaded with Ag+, Zn2+ a Cu2+ cations were successfully prepared by cation exchange reactions. Organoclays with antibacterial activity were prepared by intercalation of chlorhexidine diacetate to above mentioned monoionic clays. The resultant samples were characterized by X – ray diffraction (XRD) and infrared spectroscopy (IR). The antibacterial activity of prepared organoclays against Enterococus faecalis, Escherichia coli and Pseudomonas aeruginosa were evaluated by finding minimum inhibitory concentration (MIC). It was found that the prepared organovermiculites have better ability to inhibit bacterial growth and therefore they are more effecient than organomontmorillonites.619 - Katedra fyzikální chemie a teorie technologických pochodůvýborn

Vermiculite With Ag and Cu Used as an Antibacterial Nanofiller in Polyethylene/ Vermikulit S Ag A Cu Použitý Jako Antibakteriální Nanoplnivo V Polyethylenu

Vermikulit (Ver) obohacený stříbrem a mědí byl použit jako nanoplnivo v polyethylenové (PE) matrici. Konkrétně byl jako matrice vybrán nízko hustotní polyethylen (LDPE). Vzorky Ver-Ag,Cu byly připraveny mícháním Ver s vodnými roztoky dusičnanu stříbrného a měďnatého. Směsi Ver nanoplniv a PE byly homogenizovány postupem míchání taveniny a následně byly ze ztuhnuté směsi PE s Ver nanoplnivem vylisovány tenké destičky. Exfoliace práškového Ver nanoplniva v PE matrici byla hodnocena pomocí Rentgenové difrakční analýzy tenkých destiček. Distribuce Ver nanoplniva v PE matrici byla studována Světelnou mikroskopií. Vyztužující efekt nanoplniv na PE matrici byl studován pomocí krípového experimentu. Antibakteriální působení práškových vzorků Ver-Ag,Cu a povrchů vzorků PE/Ver-Ag,Cu bylo testováno na grampozitivní bakterii Enterococcus faecalis. Všechny testované povrchy PE/Ver-Ag,Cu vykazovaly dobré antibakteriální působení po 24 h oproti povrchu čistého PE. Počet kolonií poklesl z nespočetného množství na několik stovek kolonií

Antibacterial polyethylene/clay nanocomposites using chlorhexidine as organic modifier

The set of low density polyethylene/clay nanocomposites with increasing amount of organoclay nanofiller (3, 6 and 10 wt %) was prepared by melt compounding procedure without additives. An antimicrobial drug, chlorhexidine diacetate (CA), was loaded into Zn2+ form of clay mineral vermiculite (ZnVer) at very low concentration and then organoclay nanofiller CA/ZnVer was incorporated into polymeric matrix. The structural characteristics of all prepared samples were studied by XRD and FTIR techniques. The nanocomposites were tested for antibacterial activity against Staphylococcus aureus and Escherichia coli. Prepared samples showed a very good antibacterial activity with long lasting effect against S. aureus and slightly worse effect against E. coli.Web of Science2125224

Antibacterial activity of organomontmorillonites and organovermiculites prepared using chlorhexidine diacetate

Organoclays with antibacterial activity were prepared from cation exchanged Ag+, Cu2 + and Zn2 + forms of montmorillonite and vermiculite using five concentrations of chlorhexidine diacetate. The samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The antibacterial activity against Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa was evaluated by finding the minimum inhibitory concentration (MIC). All prepared organomontmorillonites and organovermiculites showed the best antibacterial activity against an E. coli bacterial strain.Web of Science83-84231

Preparation of antimicrobial polyethylene/inorgano-organo-vermiculite hybrid material

Clay mineral vermiculite (VT) was modified by organic surfactant hexadecyltrimethylammonium bromide, cerium and aluminum chloride solutions. Prepared materials were used as VT nanofillers to the polyethylene (PE) matrix. The composites of PE with VT nanofillers were prepared by melt compounding technique. Content of organic and inorganic constituents was determined. The X-ray diffraction patterns of VT nanofillers confirmed intercalation of organic and inorganic cations into the VT interlayer space. Antimicrobial activity of powder VT nanofillers and surfaces of PE composite plates was tested on different bacterial strains: 1) Gram-negative, Escherichia coli, 2) Gram-positive, Staphylococcus aureus, and 3) yeast, Candida albicans. The results of antimicrobial test show that powder VT nanofillers inhibited growth of tested bacteria already after 1 h of action. The surfaces of PE composites showed good antibacterial and antifungal effect against Staphylococcus aureus and Candida albicans, respectively.Web of Science1687787778

Preparation of antibacterial chlorhexidine/vermiculite and release study

The antibacterial chlorhexidine/vermiculite (CA/Ver) was successfully prepared through the intercalation process and the stability of CA on the vermiculite matrix and was investigated by stirring in aqueous solutions under the influence of different pH and temperature. The content of CA was determined by total organic carbon (TOC) analysis before and after stability tests. The structure of all samples was characterized by X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The antibacterial activity of prepared CA/Ver samples was evaluated by finding a minimum inhibitory concentration (MIC) against Entero coccus faecalis, Staphylococcus aureus, Escherichia coil and Psetidomonas aeruginosa. The content of chlorhexidine ranged from 209 to 231.6 mg of CA in 1 g of the whole sample after the intercalation process. After stability study, only a slight outflow of CA from the Ver matrix (<5%) was noted. The antibacterial test confirmed that the outflow of CA was negligible. After 30 min of exposition the MIC of organovermiculite samples before and after stability test were the same for Staphylococcus aureus and Escherichia coif with value 333 (%; w/v) and the MIC decreased to 0.014 (%; w/v) with longer time of exposition (120 h). A small difference was observed at Enterococcus faecalis where MIC was 10 (%; w/v) after 30 min of exposition for the sample after stability test in neutral pH. However, after 24 h of treatment the MIC value decreased to 0.014 (%; w/v). And finally, bacterial strain Pseudomonas aeruginosa showed a great resistance against antibacterial organovermiculite samples and MIC did not decreased under 10 (%; w/v) even after 5 days of exposition.Web of Science1596

Antibacterial efficiency of vermiculite/chlorhexidine nanocomposites and results of the in vivo test of harmlessness of vermiculite

Clay minerals have been proposed as very useful materials for modulating drug delivery. These are the commonly used materials in pharmaceutical production both as inorganic carriers or active agents. We focused on the development of suitable long-acting material for local treatment of oral infection where clay minerals act as inorganic drug carriers. Organovermiculites with antibacterial activity were prepared by ion exchange reactions using different concentrations of chlorhexidine diacetate. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal analysis (TGA). The antibacterial activity was evaluated by finding the minimum inhibitory concentration (MIC). All studied organoclays possessed good antibacterial activity after 24 h exposure against Escherichia coli, Enterococcus faecalis and particularly against Staphylococcus aureus. Pseudomonas aeruginosa however proved very resistant as only the sample with the highest concentration of CA that successfully inhibited bacterial growth. Furthermore, clay mineral vermiculite was subjected to in vivo toxicological analysis and its influence on gastrointestinal tract during its oral application was investigated. Tissue samples from buccal mucosa, tongue, esophagus, stomach, terminal duodenum, small intestine, caecum, distal colon and liver were subjected to histological examination, both macroscopically and microscopically. Neither systemic nor local reactions were observed. Therefore the toxicity of vermiculite to a mammal model organism can be excluded.Web of Science4247346

Antibacterial kaolinite/urea/chlorhexidine nanocomposites: Experiment and molecular modelling

Clay minerals are commonly used materials in pharmaceutical production both as inorganic carriers or active agents. The purpose of this study is the preparation and characterization of clay/antibacterial drug hybrids which can be further included in drug delivery systems for treatment oral infections. Novel nanocomposites with antibacterial properties were successfully prepared by ion exchange reaction from two types of kaolinite/urea intercalates and chlorhexidine diacetate. Intercalation compounds of kaolinite were prepared by reaction with solid urea in the absence of solvents (dry method) as well as with urea aqueous solution (wet method). The antibacterial activity of two prepared samples against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was evaluated by finding the minimum inhibitory concentration (MIC). Antibacterial studies of both samples showed the lowest MIC values (0.01%, w/v) after 1 day against E. faecalis, E. coli and S. aureus. A slightly worse antibacterial activity was observed against P. aeruginosa (MIC 0.12%, w/v) after 1 day. Since samples showed very good antibacterial activity, especially after 1 day of action, this means that these samples can be used as long-acting antibacterial materials. Prepared samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental data are supported by results of molecular modelling.Web of Science30579178