antimicrobial polymers
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Habilitation thesis summary
52 s. : il., tab. ; 21 cm
Tato teze habilitační práce pojednává o problematice prevence mikro-biálního osídlování polymerních povrchů.
- MeSH
- antibakteriální látky MeSH
- farmaceutické pomocné látky MeSH
- organická chemie MeSH
- polymery MeSH
- povrchové vlastnosti MeSH
- Publikační typ
- vysokoškolské kvalifikační práce MeSH
- Konspekt
- Fyzikální chemie
- NLK Obory
- chemie, klinická chemie
The diverse mechanism of antimicrobial activity of Ag and AgBr nanoparticles against gram-positive and gram-negative bacteria and also against several strains of candida was explored in this study. The AgBr nanoparticles (NPs) were prepared by simple precipitation of silver nitrate by potassium bromide in the presence of stabilizing polymers. The used polymers (PEG, PVP, PVA, and HEC) influence significantly the size of the prepared AgBr NPs dependently on the mode of interaction of polymer with Ag+ ions. Small NPs (diameter of about 60-70 nm) were formed in the presence of the polymer with low interaction as are PEG and HEC, the polymers which interact with Ag+ strongly produce nearly two times bigger NPs (120-130 nm). The prepared AgBr NPs were transformed to Ag NPs by the reduction using NaBH4. The sizes of the produced Ag NPs followed the same trends--the smallest NPs were produced in the presence of PEG and HEC polymers. Prepared AgBr and Ag NPs dispersions were tested for their biological activity. The obtained results of antimicrobial activity of AgBr and Ag NPs are discussed in terms of possible mechanism of the action of these NPs against tested microbial strains. The AgBr NPs are more effective against gram-negative bacteria and tested yeast strains while Ag NPs show the best antibacterial action against gram-positive bacteria strains.
- MeSH
- antiinfekční látky chemická syntéza chemie farmakologie MeSH
- Bacteria účinky léků MeSH
- bromidy chemie farmakologie MeSH
- Candida účinky léků MeSH
- kovové nanočástice chemie MeSH
- polymery chemie MeSH
- sloučeniny stříbra chemie farmakologie MeSH
- stříbro chemie farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Utilization of metallic nanoparticles in various biotechnological and medical applications represents one of the most extensively investigated areas of the current materials science. These advanced applications require the appropriate chemical functionalization of the nanoparticles with organic molecules or their incorporation in suitable polymer matrices. The intensified interest in polymer nanocomposites with silver nanoparticles is due to the high antimicrobial effect of nanosilver as well as the unique characteristics of polymers which include their excellent structural uniformity, multivalency, high degree of branching, miscellaneous morphologies and architectures, and highly variable chemical composition. In this review, we explore several aspects of antimicrobial polymer silver nanocomposites, giving special focus to the critical analysis of the reported synthetic routes including their advantages, drawbacks, possible improvements, and real applicability in antibacterial and antifungal therapy. A special attention is given to "green" synthetic routes exploiting the biopolymeric matrix and to the methods allowing preparing magnetically controllable antimicrobial polymers for targeting to an active place. The controversial mechanism of the action of silver against bacteria, fungi and yeasts as well as perspectives and new applications of silver polymeric nanocomposites is also briefly discussed.
- MeSH
- antibakteriální látky chemická syntéza farmakologie MeSH
- dendrimery chemie MeSH
- kovové nanočástice MeSH
- nanokompozity chemie klasifikace MeSH
- polymery chemie MeSH
- sacharidy chemie MeSH
- stříbro chemie MeSH
- velikost částic MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Surface of ultra-high-molecular-weight polyethylene (UHMWPE) was modified by chemical methods. Surface was firstly activated by Piranha solution and then grafted with selected amino-compounds (cysteamine, ethylenediamine or chitosan). The next step was grafting of some borane cluster compounds, highly fluorescent borane hydride cluster anti-B18H22 or its thiolated derivative 4,4'-(HS)2-anti-B18H20. Polymer foils were studied using various methods to characterize surface chemistry (X-ray photoelectron spectroscopy), roughness and morphology (atomic force microscopy, scanning electron microscopy), chemistry and polarity (electrokinetic analysis), wettability (goniometry) and photophysical properties (UV-Vis spectroscopy) before and after modification steps. Subsequently some kinds of antimicrobial tests were performed. Immobilization of anti-B18H22 in small quantities onto UHMWPE surface leads to materials with a luminescence. Samples grafted with borane clusters showed significant inhibition of growth for gram-positive bacteria (S. epidermidis). These approaches can be used for (i) luminophores on the base of polymers nanocomposites development and/or (ii) preparation of materials with antimicrobial effects.
Over the last decades, multidrug-resistant bacteria have emerged and spread, increasing the number of bacteria, against which commonly used antibiotics are no longer effective. It has become a serious public health problem whose solution requires medical research in order to explore novel effective antimicrobial molecules. On the one hand, antimicrobial peptides (AMPs) are regarded as good alternatives because of their generally broad-spectrum activities, but sometimes they can be easily degraded by the organism or be toxic to animal cells. On the other hand, cationic carbosilane dendrons, whose focal point can be functionalized in many different ways, have also shown good antimicrobial activity. In this work, we synthetized first- and second-generation cationic carbosilane dendrons with a maleimide molecule on their focal point, enabling their functionalization with three different AMPs. After different microbiology studies, we found an additive effect between first-generation dendron and AMP3 whose study reveals three interesting effects: (i) bacteria aggregation due to AMP3, which could facilitate bacteria detection or even contribute to antibacterial activity by preventing host cell attack, (ii) bacteria disaggregation capability of second-generation cationic dendrons, and (iii) a higher AMP3 aggregation ability when dendrons were added previously to peptide treatment. These compounds and their different effects observed over bacteria constitute an interesting system for further mechanism studies.
Antimicrobial biocompatible polymers form a group of highly desirable materials in medicinal technology that exhibit interesting thermal and mechanical properties, and high chemical resistance. There are numerous types of polymers with antimicrobial activity or antimicrobial properties conferred through their proper modification. In this review, we focus on the second type of polymers, especially those whose antimicrobial activity is conferred by nanotechnology. Nanotechnology processing is a developing area that exploits the antibacterial effects of broad-scale compounds, both organic and inorganic, to form value-added medical devices. This work gives an overview of nanostructured antimicrobial agents, especially silver ones, used together with biocompatible polymers as effective antimicrobial composites in healthcare. The bactericidal properties of non-conventional antimicrobial agents are compared with those of conventional ones and the advantages and disadvantages are discussed.
- MeSH
- antiinfekční látky aplikace a dávkování chemie MeSH
- biokompatibilní materiály chemie MeSH
- dezinfekce * metody MeSH
- infekce spojené se zdravotní péčí mikrobiologie prevence a kontrola přenos MeSH
- lidé MeSH
- nanostruktury * chemie ultrastruktura MeSH
- nanotechnologie MeSH
- polymery * chemie MeSH
- povrchové vlastnosti MeSH
- stříbro * chemie MeSH
- zdravotnické prostředky * mikrobiologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver-imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with l-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag(+) had greater activity than those doped with nanoparticles and silver-imidazole polymeric complexes. However, the antimicrobial efficiency of Ag(+) doped films was only short-term. Contrary, the antimicrobial activity of silver-imidazole/PMMA films increased in time of sample soaking.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- cystein metabolismus MeSH
- Escherichia coli účinky léků MeSH
- imidazoly chemie farmakologie MeSH
- ionty chemie MeSH
- mikrobiální testy citlivosti metody MeSH
- nanočástice chemie MeSH
- polymery chemie MeSH
- polymethylmethakrylát chemie farmakologie MeSH
- sloučeniny stříbra chemie farmakologie MeSH
- Staphylococcus epidermidis účinky léků MeSH
- stříbro chemie farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nanocomposites consisting of diatomaceous earth particles and silver nanoparticles (silver NPs) with high antimicrobial activity were prepared and characterized. For the purpose of nanocomposite preparation, silver NPs with an average size of 28nm prepared by modified Tollens process were used. Nanocomposites were prepared using poly(diallyldimethylammonium) chloride (PDDA) as an interlayer substance between diatomite and silver NPs which enables to change diatomite original negative surface charge to positive one. Due to strong electrostatic interactions between negatively charged silver NPs and positively charged PDDA-modified diatomite, Ag/PDDA-diatomite nanocomposites with a high content of silver (as high as 46.6mgAg/1g of diatomite) were prepared. Because of minimal release of silver NPs from prepared nanocomposites to aqueous media (<0.3mg Ag/1g of nanocomposite), the developed nanocomposites are regarded as a potential useful antimicrobial material with a long-term efficiency showing no risk to human health or environment. All the prepared nanocomposites exhibit a high bactericidal activity against Gram-negative and Gram-positive bacteria and fungicidal activity against yeasts at very low concentrations as low as 0.11g/L, corresponding to silver concentration of 5mg/L. Hence, the prepared nanocomposites constitute a promising candidate suitable for the microbial water treatment in environmental applications.
- MeSH
- antibakteriální látky chemická syntéza chemie farmakologie MeSH
- antifungální látky chemická syntéza chemie farmakologie MeSH
- Bacteria účinky léků MeSH
- křemelina chemie farmakologie MeSH
- kvartérní amoniové sloučeniny chemie farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- nanokompozity chemie MeSH
- organokovové sloučeniny chemická syntéza chemie farmakologie MeSH
- polyethyleny chemie farmakologie MeSH
- povrchové vlastnosti MeSH
- Saccharomyces cerevisiae účinky léků MeSH
- stříbro chemie farmakologie MeSH
- velikost částic MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Silver nanoparticles are versatile platforms with a variety of applications in the biomedical field. In this framework, their presence in biological media inevitably leads to the interaction with proteins thus conducting to the formation of biomolecular coronas. This feature alters the identity of the nanomaterial and may affect many biological events. These considerations motivated the investigation of protein adsorption onto the surface of polymer-stabilized AgNPs. The metallic colloids were coated by polyethyleneimine (PEI), polyvinylpyrrolidone (PVP), and poly(2-vinyl pyridine)-b-poly(ethylene oxide) (PEO-b-P2VP), and nanoparticle-protein interaction was probed by using a library of analytical techniques. The experimental data revealed a higher extent of protein adsorption at the surface of AgNPs@PVP whereas PEO-b-P2VP coating conducted to the least amount. The main component of the protein coronas was evidenced to be bovine serum albumin (BSA), which is indeed the protein at the highest abundancy in the model biological media. We have further demonstrated reduced cytotoxicity of the silver colloids coated by biomolecular coronas as compared to the pristine counterparts. Nevertheless, the protein coatings did not notably reduce the antimicrobial performance of the polymer-stabilized AgNPs. Accordingly, although the protein-repelling property is frequently targeted towards longer in vivo circulation of nanoparticles, we herein underline that protein coatings, which are commonly treated as artifacts to be avoided, may indeed enhance the biological performance of nanomaterials. These findings are expected to be highly relevant in the design of polymer-stabilized metallic colloids intended to be used in healthcare.
- MeSH
- antibakteriální látky farmakologie MeSH
- ethylenoxid MeSH
- koloidy MeSH
- kovové nanočástice * MeSH
- polyethylenimin farmakologie MeSH
- polymery farmakologie MeSH
- povidon farmakologie MeSH
- proteinová korona * metabolismus MeSH
- pyridiny MeSH
- sérový albumin hovězí MeSH
- stříbro farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
Cationic and amphiphilic polymers are known to exert broad-spectrum antibacterial activity by a putative mechanism of membrane disruption. Typically, nonspecific binding to hydrophobic components of the complex biological milieu, such as globular proteins, is considered a deterrent to the successful application of such polymers. To evaluate the extent to which serum deactivates antibacterial polymethacrylates, we compared their minimum inhibitory concentrations in the presence and absence of fetal bovine serum. Surprisingly, we discovered that the addition of fetal bovine serum (FBS) to the assay media in fact enhances the antimicrobial activity of polymers against Gram-positive bacteria S. aureus, whereas the opposite is the case for Gram-negative E. coli. Here, we present these unexpected trends and develop a hypothesis to potentially explain this unusual phenomenon.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence účinky léků MeSH
- Escherichia coli účinky léků MeSH
- hydrofobní a hydrofilní interakce MeSH
- kyseliny polymethakrylové farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- sérový albumin hovězí farmakologie MeSH
- Staphylococcus aureus účinky léků MeSH
- synergismus léků MeSH
- Publikační typ
- časopisecké články MeSH
