Stability and cytotoxicity of PEGylated Au NPs is crucial for biomedical application. In this study, we have focused on thermal stability of PEGylated Au NPs at 4 and 37 °C and after sterilization in autoclave. Gold nanoparticles were prepared by direct sputtering of gold into PEG and PEG-NH2. Transmission electron microscopy revealed that NPs exhibit a spherical shape with average dimensions 3.8 nm for both AuNP_PEG and AuNP_PEG-NH2. The single LSPR band at wavelength of 509 nm also confirmed presence of spherical Au NPs in both cases. Moreover, according to UV-Vis spectra, the Au NPs were overall stable during aging or thermal stressing and even after sterilization in autoclave. Based on gel electrophoresis results, the higher density of functionalizing ligands and the higher stability is assumed on AuNP_PEG-NH2. Changes in concentration of gold did not occur after thermal stress or with aging. pH values have to be adjusted to be suitable for bioapplications - original pH values are either too alkaline (AuNP_PEG-NH2, pH 10) or too acidic (AuNP_PEG, pH 5). Cytotoxicity was tested on human osteoblasts and fibroblasts. Overall, both Au NPs have shown good cytocompatibility either freshly prepared or even after Au NPs' sterilization in the autoclave. Prepared Au NP dispersions were also examined for their antiviral activity, however no significant effect was observed. We have synthesized highly stable, non-cytotoxic PEGylated Au NPs, which are ready for preclinical testing.
- Publikační typ
- časopisecké články MeSH
The present work provides an overview of the results of studies devoted to the use of two polymers, polyetheretherketone and ultrahigh molecular weight polyethylene in the field of tissue engineering. The effect of plasma modification and cathode sputtering of gold on polymer surface properties and especially on cytocompatibility of these polymers was described. Both modification steps lead to significant changes of surface properties, such as the chemical composition of the surface layer, wettability, roughness and surface morphology. These properties have a significant effect on the surface biocompatibility. Plasma modification has a beneficial effect on cell adhesion and proliferation depending on the duration of exposure. The duration of sputtering affects the size and stability of the gold nanostructures, isolated nanoclusters can partially be released into the biological solution and thus affect the cytocompatibility of the polymer.
- MeSH
- biokompatibilní materiály MeSH
- polymery * MeSH
- tkáňové inženýrství MeSH
- Publikační typ
- práce podpořená grantem MeSH
In this study, we have aimed at the preparation and characterization of poly-l-lactic acid (PLLA) composites with antibacterial properties. Thin bilayers of titanium and gold of various thickness ratios were deposited on PLLA by a cathode sputtering method; selected samples were subsequently thermally treated. The surface morphology of the prepared composites was studied by atomic force, scanning electron, and laser confocal microscopy. The chemical properties of the composites were determined by X-ray photoelectron and energy-dispersive X-ray spectroscopy in combination with contact angle and zeta potential analyses. The antibacterial properties of selected samples were examined against a Gram-negative bacterial strain of E. coli. We have found that a certain combination of Au and Ti nanolayers in combination with heat treatment leads to the formation of a unique wrinkled pattern. Moreover, we have developed a simple technique by which a large-scale sample modification can be easily produced. The dimensions of wrinkles can be tailored by the sequence and thickness of the deposited metals. A selected combination of gold, titanium, and heat treatment led to the formation of a nanowrinkled pattern with excellent antibacterial properties.
- Publikační typ
- časopisecké články MeSH
We have developed a novel simple method for effective preparing gold nanoparticles (AuNPs) intended for utilization in biomedicine. The method is based on gold sputtering into liquid poly(ethylene glycol) (PEG). The PEG was used as a basic biocompatible stabilizer of the AuNP colloid. In addition, two naturally occurring polysaccharides - Chitosan (Ch) and Methylcellulose (MC) - were separately diluted into the PEG base with the aims to enhance the yield of the sputtering without changing the sputtering parameters, and to further improve the stability and the biocompatibility of the colloid. The colloids were sterilized by steam, and their stability was measured before and after the sterilization process by dynamic light scattering and UV-Vis spectrophotometry. The results indicated a higher sputtering yield in the colloids containing the polysaccharides. The colloids were also characterized by atomic absorption spectroscopy (AAS) to reveal the composition of the prepared nanoparticles by transmission electron microscopy (TEM) to visualize the nanoparticles and to evaluate their size and clustering, and by rheometry to estimate the viscosity of the colloids. The zeta-potential of the AuNPs was also determined as an important parameter indicating the stability and the biocompatibility of the colloid. In addition, in vitro tests of antimicrobial activity and cytotoxicity were carried out to estimate the biological activity and the biocompatibility of the colloids. Antimicrobial tests were performed by a drip test on two bacterial strains - Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli. AuNP with chitosan proved to possess the highest antibacterial activity, especially towards the Gram-positive S. epidermidis. In vitro tests on eukaryotic cells, i.e. human osteoblastic cell line SAOS-2 and primary normal human dermal fibroblasts (NHDF), were performed after a 7-day cultivation to determine the effect and the toxic dose of the colloids on human cells. The studied colloid concentrations were in the range from 0.6 μg/ml to 6 μg/ml. Toxicity of the colloids started to reappear at a concentration of 4.5 μg/ml, especially with chitosan in the colloid, where the colloid with a concentration of 6 μg/ml proved to be the most toxic, especially towards the SAOS-2 cell line. However, the PEG and PEG-MC containing colloids proved to be relatively non-toxic, even at the highest concentration, but with a slowly decreasing tendency of the cell metabolic activity.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- buněčné linie MeSH
- chitosan chemie MeSH
- dynamický rozptyl světla MeSH
- Escherichia coli účinky léků MeSH
- koloidy chemie MeSH
- kovové nanočástice chemie MeSH
- lidé MeSH
- methylcelulosa chemie MeSH
- polysacharidy chemie MeSH
- stabilita léku MeSH
- Staphylococcus epidermidis účinky léků MeSH
- sterilizace MeSH
- velikost částic MeSH
- zlato chemie farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Remote detection of hydrogen, without the utilization of electronic component or elevated temperature, is one of the hot topics in the hydrogen technology and safety. In this work, the design and realization of the optical fiber-based hydrogen sensor with unique characteristics are proposed. The proposed sensor is based on the gold-coated multimode fiber, providing the plasmon properties, decorated by the IRMOF-20 layer with high selectivity and affinity toward hydrogen. The IRMOF-20 layer was grown by a surface-assisted technique, and its formation and properties were studied using X-ray photoelectron spectroscopy, Raman, X-ray diffraction, and Brunauer-Emmett-Teller techniques. Simultaneous ellipsometry results indicate the apparent changes of the refractive index of the IRMOF-20 layer due to hydrogen sorption. As results, the presence of hydrogen led to the pronounced changes of plasmon band wavelength position as well as its intensity increase. The proposed hydrogen sensors were favorably distinguished by a high response/recovery rate, excellent selectivity toward the hydrogen, very low temperature dependency, functionality at room or lower temperature, insensitivity toward the humidity, and the presence of CO2, CO, or NO2. Additionally, the proposed hydrogen sensor showed good reversibility, reproducibility, and long-term stability.
Stable antimicrobial nanofibrous membrane for air filtration based on polyamide 6 (hereafter PA6) modified by 1-dodecyltrimethylammonium bromide (DTAB) has been prepared by electrospinning using one-step technology, i.e. with modifying antimicrobial agent dissolved in spinning solution. Stability of antibacterial membrane function has been tested by air-blowing test to prove the permanency of chemical composition and antibacterial activity. X-ray diffraction, high-resolution scanning electron microscopy (HRSEM) revealed the effect of modifying agent on structure and morphology of PA6 nanofibres. X-ray photoelectron spectroscopy, electrokinetic analysis and antibacterial tests proved the stability of chemical composition and antibacterial activity after air-blowing tests. Special air-blowing device has been constructed for this purpose. The results prove the applicability so prepared membrane for a long-term air-conditioning.
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.
This work deals with the surface properties of several polymer foils and their changes before and after UV irradiation and subsequent grafting with cysteamine. The surface wettability was determined by goniometry from static contact angle measurement. Surface chemistry, polarity and charge were studied by the electrokinetic analysis. Chemical composition of surface was characterized by X-ray photoelectron spectroscopy. All of the employed methods confirmed a successful surface activation by UV radiation and chemical modification by cysteamine grafting. These changes depend strongly on exposure time of UV radiation.
- MeSH
- polymery * chemie účinky záření MeSH
- povrchové vlastnosti účinky záření MeSH
- ultrafialové záření MeSH
- Publikační typ
- práce podpořená grantem MeSH
Stem cells can be defined as units of biological organization that are responsible for the development and the regeneration of organ and tissue systems. They are able to renew their populations and to differentiate into multiple cell lineages. Therefore, these cells have great potential in advanced tissue engineering and cell therapies. When seeded on synthetic or nature-derived scaffolds in vitro, stem cells can be differentiated towards the desired phenotype by an appropriate composition, by an appropriate architecture, and by appropriate physicochemical and mechanical properties of the scaffolds, particularly if the scaffold properties are combined with a suitable composition of cell culture media, and with suitable mechanical, electrical or magnetic stimulation. For cell therapy, stem cells can be injected directly into damaged tissues and organs in vivo. Since the regenerative effect of stem cells is based mainly on the autocrine production of growth factors, immunomodulators and other bioactive molecules stored in extracellular vesicles, these structures can be isolated and used instead of cells for a novel therapeutic approach called "stem cell-based cell-free therapy". There are four main sources of stem cells, i.e. embryonic tissues, fetal tissues, adult tissues and differentiated somatic cells after they have been genetically reprogrammed, which are referred to as induced pluripotent stem cells (iPSCs). Although adult stem cells have lower potency than the other three stem cell types, i.e. they are capable of differentiating into only a limited quantity of specific cell types, these cells are able to overcome the ethical and legal issues accompanying the application of embryonic and fetal stem cells and the mutational effects associated with iPSCs. Moreover, adult stem cells can be used in autogenous form. These cells are present in practically all tissues in the organism. However, adipose tissue seems to be the most advantageous tissue from which to isolate them, because of its abundancy, its subcutaneous location, and the need for less invasive techniques. Adipose tissue-derived stem cells (ASCs) are therefore considered highly promising in present-day regenerative medicine.
- MeSH
- buněčná diferenciace MeSH
- kmenové buňky * cytologie fyziologie MeSH
- lidé MeSH
- myši MeSH
- regenerativní lékařství * MeSH
- tkáňové inženýrství * MeSH
- transplantace kmenových buněk * MeSH
- tuková tkáň cytologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Herein, we report a novel concept of low-cost flexible platform for fluorescence-based biosensor. The surface of polyethylene naphthalate (PEN) foil was exposed to KrF excimer laser through a photolitographic contact mask. Laser initiated surface modification resulted in micro-patterned areas with surface functional groups available for localized covalent immobilization of biotin. High affinity binding protein (albumin-binding domain (ABD) of protein G, Streptococcus G148) recognizing human serum albumin (HSA), genetically fused with streptavidin (SA-ABDwt), was immobilized on the micro-patterned surface through biotin-streptavidin coupling. Fluorescently labelled HSA analyte was detected in several blocking environments, in 1% bovine serum albumin (BSA) and 6% fetal serum albumin (FBS), respectively. We conclude that the presented novel concept enabled us to micropattern functional biosensing layers on the surface of PEN foil in a fast and easy way. It brings all necessary aspects for continuous roll-to-roll fabrication of low-cost optical bioanalytical devices.
- MeSH
- biotin metabolismus MeSH
- fotoelektronová spektroskopie MeSH
- lidé MeSH
- mikrotechnologie metody MeSH
- naftaleny chemie MeSH
- optické jevy * MeSH
- polyethyleny chemie MeSH
- povrchové vlastnosti MeSH
- sérový albumin metabolismus MeSH
- streptavidin metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
