Publications by authors named "Petr Slepička"

37 Publications

Acidic pH Is Required for the Multilamellar Assembly of Skin Barrier Lipids In Vitro.

J Invest Dermatol 2021 Mar 3. Epub 2021 Mar 3.

Faculty of Pharmacy in Hradec Králové, Charles University, Hradec Králové, Czech Republic. Electronic address:

Lipid membrane remodeling belongs to the most fundamental processes in the body. The skin barrier lipids, which are ceramide dominant and highly rigid, must attain an unusual multilamellar nanostructure with long periodicity to restrict water loss and prevent the entry of potentially harmful environmental factors. Our data suggest that the skin acid mantle, apart from regulating enzyme activities and keeping away pathogens, may also be a prerequisite for the multilamellar assembly of the skin barrier lipids. Atomic force microscopy on monolayers composed of synthetic or human stratum corneum lipids showed multilayer formation (approximately 10-nm step height) in an acidic but not in a neutral environment. X-ray diffraction, Fourier transform infrared spectroscopy, and permeability studies showed markedly altered lipid nanostructure and increased water loss at neutral pH compared with that at acidic pH. These findings are consistent with the data on the altered organization of skin lipids and increased transepidermal water loss under conditions such as inadequate skin acidification, for example, in neonates, the elderly, and patients with atopic dermatitis.
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http://dx.doi.org/10.1016/j.jid.2021.02.014DOI Listing
March 2021

Cell Behavior of Primary Fibroblasts and Osteoblasts on Plasma-Treated Fluorinated Polymer Coated with Honeycomb Polystyrene.

Materials (Basel) 2021 Feb 13;14(4). Epub 2021 Feb 13.

Department of Solid State Engineering, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague, Czech Republic.

The development of new biocompatible polymer substrates is still of interest to many research teams. We aimed to combine a plasma treatment of fluorinated ethylene propylene (FEP) substrate with a technique of improved phase separation. Plasma exposure served for substrate activation and modification of surface properties, such as roughness, chemistry, and wettability. The treated FEP substrate was applied for the growth of a honeycomb-like pattern from polystyrene solution. The properties of the pattern strongly depended on the primary plasma exposure of the FEP substrate. The physico-chemical properties such as changes of the surface chemistry, wettability, and morphology of the prepared pattern were determined. The cell response of primary fibroblasts and osteoblasts was studied on a honeycomb pattern. The prepared honeycomb-like pattern from polystyrene showed an increase in cell viability and a positive effect on cell adhesion and proliferation for both primary fibroblasts and osteoblasts.
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http://dx.doi.org/10.3390/ma14040889DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918735PMC
February 2021

Differentiation of adipose tissue-derived stem cells towards vascular smooth muscle cells on modified poly(L-lactide) foils.

Biomed Mater 2021 Feb 18;16(2):025016. Epub 2021 Feb 18.

Department of Biomaterials and Tissue Engineering, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 142 20, Prague 4, Czech Republic. Second Faculty of Medicine, Charles University, V Uvalu 84, 150 06, Prague 5, Czech Republic.

The aim of our research was to study the behaviour of adipose tissue-derived stem cells (ADSCs) and vascular smooth muscle cells (VSMCs) on variously modified poly(L-lactide) (PLLA) foils, namely on pristine PLLA, plasma-treated PLLA, PLLA grafted with polyethylene glycol (PEG), PLLA grafted with dextran (Dex), and the tissue culture polystyrene (PS) control. On these materials, the ADSCs were biochemically differentiated towards VSMCs by a medium supplemented with TGFβ1, BMP4 and ascorbic acid (i.e. differentiation medium). ADSCs cultured in a non-differentiation medium were used as a negative control. Mature VSMCs cultured in both types of medium were used as a positive control. The impact of the variously modified PLLA foils and/or differences in the composition of the medium were studied with reference to cell adhesion, growth and differentiation. We observed similar adhesion and growth of ADSCs on all PLLA samples when they were cultured in the non-differentiation medium. The differentiation medium supported the expression of specific early, mid-term and/or late markers of differentiation (i.e. type I collagen, αSMA, calponin, smoothelin, and smooth muscle myosin heavy chain) in ADSCs on all tested samples. Moreover, ADSCs cultured in the differentiation medium revealed significant differences in cell growth among the samples that were similar to the differences observed in the cultures of VSMCs. The round morphology of the VSMCs indicated worse adhesion to pristine PLLA, and this sample was also characterized by the lowest cell proliferation. Culturing VSMCs in the differentiation medium inhibited their metabolic activity and reduced the cell numbers. Both cell types formed the most stable monolayer on plasma-treated PLLA and on the PS control. The behaviour of ADSCs and VSMCs on the tested PLLA foils differed according to the specific cell type and culture conditions. The suitable biocompatibility of both cell types on the tested PLLA foils seems to be favourable for vascular tissue engineering purposes.
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http://dx.doi.org/10.1088/1748-605X/abaf97DOI Listing
February 2021

Antibacterial Properties of Plasma-Activated Perfluorinated Substrates with Silver Nanoclusters Deposition.

Nanomaterials (Basel) 2021 Jan 13;11(1). Epub 2021 Jan 13.

Department of Solid State Engineering, University of Chemistry and Technology Prague, 166 28 Prague, Czech Republic.

This article is focused on the evaluation of surface properties of polytetrafluoroethylene (PTFE) nanotextile and a tetrafluoroethylene-perfluoro(alkoxy vinyl ether) (PFA) film and their surface activation with argon plasma treatment followed with silver nanoclusters deposition. Samples were subjected to plasma modification for a different time exposure, silver deposition for different time periods, or their combination. As an alternative approach, the foils were coated with poly-L-lactic acid (PLLA) and silver. The following methods were used to study the surface properties of the polymers: goniometry, atomic force microscopy, and X-ray photoelectron microscopy. By combining the aforementioned methods for material surface modification, substrates with antibacterial properties eliminating the growth of Gram-positive and Gram-negative bacteria were prepared. Studies of antimicrobial activity showed that PTFE plasma-modified samples coated with PLLA and deposited with a thin layer of Ag had a strong antimicrobial effect, which was also observed for the PFA material against the bacterial strain of . Significant antibacterial effect against , and has been demonstrated on PTFE nanotextile plasma-treated for 240 s, coated with PLLA, and subsequently sputtered with thin Ag layer.
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http://dx.doi.org/10.3390/nano11010182DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828452PMC
January 2021

Optomechanical Processing of Silver Colloids: New Generation of Nanoparticle-Polymer Composites with Bactericidal Effect.

Int J Mol Sci 2020 Dec 30;22(1). Epub 2020 Dec 30.

Biology Centre of the Czech Academy of Sciences, SoWa National Research Infrastructure, Na Sádkách 7, 370 05 České Budejovice, Czech Republic.

The properties of materials at the nanoscale open up new methodologies for engineering prospective materials usable in high-end applications. The preparation of composite materials with a high content of an active component on their surface is one of the current challenges of materials engineering. This concept significantly increases the efficiency of heterogeneous processes moderated by the active component, typically in biological applications, catalysis, or drug delivery. Here we introduce a general approach, based on laser-induced optomechanical processing of silver colloids, for the preparation of polymer surfaces highly enriched with silver nanoparticles (AgNPs). As a result, the AgNPs are firmly immobilized in a thin surface layer without the use of any other chemical mediators. We have shown that our approach is applicable to a broad spectrum of polymer foils, regardless of whether they absorb laser light or not. However, if the laser radiation is absorbed, it is possible to transform smooth surface morphology of the polymer into a roughened one with a higher specific surface area. Analyses of the release of silver from the polymer surface together with antibacterial tests suggested that these materials could be suitable candidates in the fight against nosocomial infections and could inhibit the formation of biofilms with a long-term effect.
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http://dx.doi.org/10.3390/ijms22010312DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794995PMC
December 2020

PLLA Honeycomb-Like Pattern on Fluorinated Ethylene Propylene as a Substrate for Fibroblast Growth.

Polymers (Basel) 2020 Oct 22;12(11). Epub 2020 Oct 22.

Department of Solid State Engineering, University of Chemistry and Technology Prague, 166 28 Prague, Czech Republic.

In this study, we present the surface patterning of a biopolymer poly(l-lactide) (PLLA) for fibroblast growth enhancement. The patterning is based on a self-organized pore arrangement directly fabricated from a ternary system of a solvent-nonsolvent biopolymer. We successfully created a porous honeycomb-like pattern (HCP) on a thermally resistant polymer-fluorinated ethylene propylene (FEP). An important preparation step for HCP is activation of the substrate in Ar plasma discharge. The polymer activation leads to changes in the surface chemistry, which corresponds to an increase in the substrate surface wettability. The aim of this study was to evaluate the influence of the PLLA concentration in solution on the surface morphology, roughness, wettability, and chemistry, and subsequently, also on fibroblast proliferation. We confirmed that the amount of PLLA in solution significantly affects the material surface properties. The pore size of the prepared layers, the surface wettability, and the surface oxygen content increased with an increasing amount of biopolymer in the coating solution. The optimal amount was 1 g of PLLA, which resulted in the highest number of cells after 6 days from seeding; however, all three biopolymer concentrations exhibited significantly better results compared to pristine FEP. The cytocompatibility tests showed that the HCP promoted the attachment of cell filopodia to the underlying substrate and, thus, significantly improved the cell-material interactions. We prepared a honeycomb biodegradable support for enhanced cell growth, so the surface properties of perfluoroethylenepropylene were significantly enhanced.
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http://dx.doi.org/10.3390/polym12112436DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7690597PMC
October 2020

Nanostructured Polystyrene Doped with Acetylsalicylic Acid and Its Antibacterial Properties.

Materials (Basel) 2020 Aug 14;13(16). Epub 2020 Aug 14.

Department of Solid State Engineering, University of Chemistry and Technology Prague, 16628 Prague, Czech Republic.

Homogeneous polystyrene foils doped with different concentrations of acetylsalicylic acid were prepared by the solvent casting method. The surface morphology and surface chemistry of as-prepared foils were characterized in detail. Excimer laser (krypton fluoride, a wavelength of 248 nm) was used for surface nanopatterning of doped polystyrene foils. Certain combinations of laser fluence and number of laser pulses led to formation of laser-induced periodic surface structures (LIPSS) on the exposed surface. Formation of the pattern was affected by the presence of a dopant in the polystyrene structure. Significant differences in surface chemistry and morphology of laser-treated foils compared to both pristine and doped polystyrene were detected. The pattern width and height were both affected by selection of input excimer exposure conditions, and the amount of 6000 pulses was determined as optimal. The possibility of nanostructuring of a honeycomb-like pattern doped with acetylsalicylic acid was also demonstrated. Selected nanostructured surfaces were used for study the antibacterial properties for a model bacteria strain of . The combination of altered surface chemistry and morphology of polystyrene was confirmed to have an excellent antibacterial properties.
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http://dx.doi.org/10.3390/ma13163609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7475827PMC
August 2020

The effect of gold and silver nanoparticles, chitosan and their combinations on bacterial biofilms of food-borne pathogens.

Biofouling 2020 02 22;36(2):222-233. Epub 2020 Apr 22.

Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic.

The antimicrobial activity of gold and silver nanoparticles (AuNPs, AgNPs), chitosan (CS) and their combinations was established by determining the minimum inhibitory concentration for planktonic (MICPC) and biofilm growth (MICBC), for biofilm formation (MICBF), metabolic activity (MICBM) and reduction (MICBR), and for the metabolic activity of preformed biofilm (MICMPB). Biofilms were quantified in microtitre plates by crystal violet staining and metabolic activity was evaluated by the MTT assay. Chitosan effectively suppressed biofilm formation (0.31-5 mg ml) in all the tested strains, except Infantis (0.16-2.5 mg ml) where CS and its combination with AgNPs induced biofilm formation. Nanoparticles inhibited biofilm growth only when the highest concentrations were used. Even though AuNPs, AgNPs and CS were not able to remove biofilm mass, they reduced its metabolic activity by at least 80%. The combinations of nanoparticles with CS did not show any significant positive synergistic effect on the tested target properties.
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http://dx.doi.org/10.1080/08927014.2020.1751132DOI Listing
February 2020

Methods of Gold and Silver Nanoparticles Preparation.

Materials (Basel) 2019 Dec 18;13(1). Epub 2019 Dec 18.

Department of Solid State Engineering, The University of Chemistry and Technology, 166 28 Prague, Czech Republic.

The versatile family of nanoparticles is considered to have a huge impact on the different fields of materials research, mostly nanoelectronics, catalytic chemistry and in study of cytocompatibility, targeted drug delivery and tissue engineering. Different approaches for nanoparticle preparation have been developed, not only based on "bottom up" and "top down" techniques, but also several procedures of effective nanoparticle modifications have been successfully used. This paper is focused on different techniques of nanoparticles' preparation, with primary focus on metal nanoparticles. Dispergation methods such as laser ablation and vacuum sputtering are introduced. Condensation methods such as reduction with sodium citrate, the Brust-Schiffrin method and approaches based on ultraviolet light or biosynthesis of silver and gold are also discussed. Basic properties of colloidal solutions are described. Also a historical overview of nanoparticles are briefly introduced together with short introduction to specific properties of nanoparticles and their solutions.
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http://dx.doi.org/10.3390/ma13010001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6981963PMC
December 2019

LIPSS Structures Induced on Graphene-Polystyrene Composite.

Materials (Basel) 2019 Oct 23;12(21). Epub 2019 Oct 23.

Department of Solid State Engineering, University of Chemistry and Technology Prague, 166 28 Prague, Czech Republic.

A laser induced periodic surface structure (LIPSS) on graphene doped polystyrene was prepared by the means of a krypton fluoride (KrF) laser with the wavelength of 248 nm and precisely desired physico-chemical properties were obtained for the structure. Surface morphology after laser modification of polystyrene (PS) doped with graphene nanoplatelets (GNP) was studied. Laser fluence values of modifying laser light varied between 0-40 mJ·cm and were used on polymeric PS substrates doped with 10, 20, 30, and 40 wt. % of GNP. GNP were incorporated into PS substrate with the solvent casting method and further laser modification was achieved with the same amount of laser pulses of 6000. Formed nanostructures with a periodic pattern were examined by atomic force microscopy (AFM). The morphology was also studied with scanning electron microscopy SEM. Laser irradiation resulted in changes of chemical composition on the PS surface, such as growth of oxygen concentration. This was confirmed with energy-dispersive X-ray spectroscopy (EDS).
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http://dx.doi.org/10.3390/ma12213460DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6861962PMC
October 2019

Argon plasma-treated fluorinated ethylene propylene: Growth of primary dermal fibroblasts and mesenchymal stem cells.

Tissue Cell 2019 Jun 14;58:121-129. Epub 2019 May 14.

Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague 6, Czech Republic. Electronic address:

Surface modification is an important step in making a synthetic polymer cytocompatible. We have previously reported improved cytocompatibility of immortalized human keratinocytes (HaCaT) with the otherwise bioinert fluorinated ethylene propylene (FEP) upon treatment with argon plasma discharge. In this article, we show that FEP modified with Ar plasma with the power of 3 and 8 W for 40 and 240 s served as a suitable material for cultivation of primary human dermal fibroblasts (HDF), which showed significantly improved proliferation and spreading comparable to standard tissue culture polystyrene. We also evaluated focal adhesions formed by HDF cells on modified FEP, which were far more numerous compared to pristine FEP. Moreover, we attempted spontaneous osteogenic differentiation of adipose-derived mesenchymal stem cells modified with human telomerase reverse transcriptase on Ar plasma-modified FEP. While the spontaneous osteogenic differentiation was unsuccessful, the cells were able to adhere and differentiated on tested matrices upon the administration of osteodifferentiation medium. These combined findings suggest that the treatment of FEP with Ar plasma comprises and efficient method to enable the adhesion and proliferation of various cell types on an otherwise largely bioinert material.
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http://dx.doi.org/10.1016/j.tice.2019.05.004DOI Listing
June 2019

Biocompatibility of Ar plasma-treated fluorinated ethylene propylene: Adhesion and viability of human keratinocytes.

Mater Sci Eng C Mater Biol Appl 2019 Jul 27;100:269-275. Epub 2019 Feb 27.

Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic. Electronic address:

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http://dx.doi.org/10.1016/j.msec.2019.02.100DOI Listing
July 2019

Heat-treated carbon coatings on poly (l-lactide) foils for tissue engineering.

Mater Sci Eng C Mater Biol Appl 2019 Jul 28;100:117-128. Epub 2019 Feb 28.

Department of Biomaterials and Tissue Engineering, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic.

Carbon-based materials have emerged as promising candidates for a wide variety of biomedical applications, including tissue engineering. We have developed a simple but unique technique for patterning carbon-based substrates in order to control cell adhesion, growth and phenotypic maturation. Carbon films were deposited on PLLA foils from distances of 3 to 7 cm. Subsequent heat-treatment (60 °C, 1 h) created lamellar structures with dimensions decreasing from micro- to nanoscale with increasing deposition distance. All carbon films improved the spreading and proliferation of human osteoblast-like MG 63 cells, and promoted the alignment of these cells along the lamellar structures. Similar alignment was observed in human osteoblast-like Saos-2 cells and in human dermal fibroblasts. Type I collagen fibers produced by Saos-2 cells and fibroblasts were also oriented along the lamellar structures. These structures increased the activity of alkaline phosphatase in Saos-2 cells. Carbon coatings also supported adhesion and growth of vascular endothelial and smooth muscle cells, particularly flatter non-heated carbon films. On these films, the continuity of the endothelial cell layer was better than on heat-treated lamellar surfaces. Heat-treated carbon-coated PLLA is therefore more suitable for bone and skin tissue engineering, while carbon-coated PLLA without heating is more appropriate for vascular tissue engineering.
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http://dx.doi.org/10.1016/j.msec.2019.02.105DOI Listing
July 2019

Antimicrobial and photophysical properties of chemically grafted ultra-high-molecular-weight polyethylene.

Mater Sci Eng C Mater Biol Appl 2019 Mar 28;96:479-486. Epub 2018 Nov 28.

J. E. Purkyně, Ústí nad Labem, Faculty of Science, Materials Centre and Department of Physics, České Mládeže 8, 400 96 Ústí nad Labem, Czechia.

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-BH or its thiolated derivative 4,4'-(HS)-anti-BH. 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-BH 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.
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http://dx.doi.org/10.1016/j.msec.2018.11.066DOI Listing
March 2019

Stem cells: their source, potency and use in regenerative therapies with focus on adipose-derived stem cells - a review.

Biotechnol Adv 2018 Jul - Aug;36(4):1111-1126. Epub 2018 Mar 18.

Clinic of Plastic Surgery, Faculty Hospital Na Bulovce, Budinova 67/2, 180 81 Prague, 8-Liben, Czech Republic.

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.
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http://dx.doi.org/10.1016/j.biotechadv.2018.03.011DOI Listing
February 2019

A simple approach for fabrication of optical affinity-based bioanalytical microsystem on polymeric PEN foils.

Colloids Surf B Biointerfaces 2018 May 2;165:28-36. Epub 2018 Feb 2.

Department of Biology and Material Centre, Faculty of Science, University of J.E. Purkinje, 400 96 Ústí nad Labem, Czech Republic.

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.
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http://dx.doi.org/10.1016/j.colsurfb.2018.01.048DOI Listing
May 2018

Polymer nanostructures for bioapplications induced by laser treatment.

Biotechnol Adv 2018 May - Jun;36(3):839-855. Epub 2017 Dec 16.

Department of Solid State Engineering, University of Chemistry and Technology, Technická 5, Prague, Czech Republic. Electronic address:

Modification of polymer substrates can essentially change the properties of material and thereby it allows their usage in attractive fields of material research. Laser treatment can be successfully applied for change in physico-chemical surface properties and/or for selective change of surface morphology with pattern construction. Three major applications of laser induced structures were described, cytocompatibility control, application as anti-bacterial substrate and plasmonic-based detection system. The construction of a second generation antibacterials using the synergic effect of either nanopatterning of polymers by application of a laser or noble metals deposition and consequent modification of nanostructures was presented.
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http://dx.doi.org/10.1016/j.biotechadv.2017.12.011DOI Listing
February 2019

Surface Modification of Polymer Substrates for Biomedical Applications.

Materials (Basel) 2017 Sep 21;10(10). Epub 2017 Sep 21.

Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague, Czech Republic.

While polymers are widely utilized materials in the biomedical industry, they are rarely used in an unmodified state. Some kind of a surface treatment is often necessary to achieve properties suitable for specific applications. There are multiple methods of surface treatment, each with their own pros and cons, such as plasma and laser treatment, UV lamp modification, etching, grafting, metallization, ion sputtering and others. An appropriate treatment can change the physico-chemical properties of the surface of a polymer in a way that makes it attractive for a variety of biological compounds, or, on the contrary, makes the polymer exhibit antibacterial or cytotoxic properties, thus making the polymer usable in a variety of biomedical applications. This review examines four popular methods of polymer surface modification: laser treatment, ion implantation, plasma treatment and nanoparticle grafting. Surface treatment-induced changes of the physico-chemical properties, morphology, chemical composition and biocompatibility of a variety of polymer substrates are studied. Relevant biological methods are used to determine the influence of various surface treatments and grafting processes on the biocompatibility of the new surfaces-mammalian cell adhesion and proliferation is studied as well as other potential applications of the surface-treated polymer substrates in the biomedical industry.
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http://dx.doi.org/10.3390/ma10101115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5666921PMC
September 2017

BODIPY-based fluorescent liposomes with sesquiterpene lactone trilobolide.

Beilstein J Org Chem 2017 4;13:1316-1324. Epub 2017 Jul 4.

Department of Chemistry of Natural Compounds, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic.

Like thapsigargin, which is undergoing clinical trials, trilobolide is a natural product with promising anticancer and anti-inflammatory properties. Similar to thapsigargin, it has limited aqueous solubility that strongly reduces its potential medicinal applications. The targeted delivery of hydrophobic drugs can be achieved using liposome-based carriers. Therefore, we designed a traceable liposomal drug delivery system for trilobolide. The fluorescent green-emitting dye BODIPY, cholesterol and trilobolide were used to create construct . The liposomes were composed of dipalmitoyl-3-trimethylammoniumpropane and phosphatidylethanolamine. The whole system was characterized by atomic force microscopy, the average size of the liposomes was 150 nm in width and 30 nm in height. We evaluated the biological activity of construct and its liposomal formulation, both of which showed immunomodulatory properties in primary rat macrophages. The uptake and intracellular distribution of construct and its liposomal formulation was monitored by means of live-cell fluorescence microscopy in two cancer cell lines. The encapsulation of construct into the liposomes improved the drug distribution in cancer cells and was followed by cell death. This new liposomal trilobolide derivative not only retains the biological properties of pure trilobolide, but also enhances the bioavailability, and thus has potential for the use in theranostic applications.
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http://dx.doi.org/10.3762/bjoc.13.128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5530629PMC
July 2017

Permeability and microstructure of model stratum corneum lipid membranes containing ceramides with long (C16) and very long (C24) acyl chains.

Biophys Chem 2017 05 21;224:20-31. Epub 2017 Mar 21.

Skin Barrier Research Group, Charles University, Faculty of Pharmacy in Hradec Králové, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.

The Stratum corneum (SC) prevents water loss from the body and absorption of chemicals. SC intercellular spaces contain ceramides (Cer), free fatty acids (FFA), cholesterol (Chol) and cholesteryl sulfate (CholS). Cer with "very long" acyl chains (for example, N-lignoceroyl-sphingosine, CerNS24) are important for skin barrier function, whereas increased levels of "long" acyl Cer (for example, N-palmitoyl-sphingosine, CerNS16) occur in patients suffering from atopic eczema or psoriasis. We studied the impact of the replacement of CerNS24 by CerNS16 on the barrier properties and microstructure of model SC lipid membranes composed of Cer/FFA/Chol/CholS. Membranes containing the long CerNS16 were significantly more permeable to water (by 38-53%), theophylline (by 50-55%) and indomethacin (by 83-120%) than those containing the very long CerNS24 (either with lignoceric acid or a mixture of long to very long chain FFA). Langmuir monolayers with CerNS24 were more condensed than with CerNS16 and atomic force microscopy showed differences in domain formation. X-ray powder diffraction revealed that CerNS24-based membranes formed one lamellar phase and separated Chol, whereas the CerNS16-based membranes formed up to three phases and Chol. These results suggest that replacement of CerNS24 by CerNS16 has a direct negative impact on membrane structure and permeability.
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http://dx.doi.org/10.1016/j.bpc.2017.03.004DOI Listing
May 2017

Temperature-responsive PLLA/PNIPAM nanofibers for switchable release.

Mater Sci Eng C Mater Biol Appl 2017 Mar 9;72:293-300. Epub 2016 Nov 9.

Department of Solid State Engineering, University of Chemistry and Technology, Prague 166 28, Czech Republic. Electronic address:

Smart antimicrobial materials with on-demand drug release are highly desired for biomedical applications. Herein, we report about temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) nanospheres doped with crystal violet (CV) and incorporated into the poly-l-lactide (PLLA) nanofibers. The nanofibers were prepared by electrospinning, using different initial polymers ratios. The morphology of the nanofibers and polymers distribution in the nanofibers were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The interaction between PNIPAM and PLLA in the nanofibers was studied by Fourier transform infrared spectroscopy (FTIR) and its effect on the PNIPAM phase transition was also investigated. It was shown that by the changing of the environmental temperature across the lower critical solution temperature (LCST) of PNIPAM, the switchable wettability and controlled CV release can be achieved. The temperature-dependent release kinetics of CV from polymer nanofibers was investigated by ultraviolet-visible spectroscopy (UV-Vis). The temperature-responsive release of antibacterial CV was also tested for triggering of antibacterial activity, which was examined on Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli). Thus, the proposed material is promising value for controllable drug-release.
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http://dx.doi.org/10.1016/j.msec.2016.11.028DOI Listing
March 2017

Cytocompatibility of amine functionalized carbon nanoparticles grafted on polyethylene.

Mater Sci Eng C Mater Biol Appl 2016 Mar 25;60:394-401. Epub 2015 Nov 25.

Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6, Czech Republic.

Five types of amide-amine Carbon Nano-Particles (CNPs) were prepared by functionalization of CNPs and characterized by several analytical methods. The successful grafting of amines on CNPs was verified by X-ray photoelectron spectroscopy (XPS), organic elemental analysis and electrokinetic analysis. The size and morphology of CNPs were determined from transmission electron microscopy. The surface area and porosity of CNPs were examined by adsorption and desorption isotherms. Differential scanning calorimetry was used to investigate thermal stability of CNPs. The amount of bonded amine depends on its dimensionality arrangement. Surface area and pore volumes of CNPs decrease several times after individual amino-compound grafting. Selected types of functionalized CNPs were grafted onto a plasma activated surface of HDPE. The successful grafting of CNPs on the polymer surface was verified by XPS. Wettability was determined by contact angle measurements. Surface morphology and roughness were studied by atomic force microscopy. A dramatic decrease of contact angle and surface morphology was observed on CNP grafted polymer surface. Cytocompatibility of modified surfaces was studied in vitro, by determination of adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs). Grafting of CNPs onto the polymer surface has a positive effect on the adhesion, proliferation and viability of VSMCs.
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http://dx.doi.org/10.1016/j.msec.2015.11.058DOI Listing
March 2016

Direct immobilization of biotin on the micro-patterned PEN foil treated by excimer laser.

Colloids Surf B Biointerfaces 2015 Apr 21;128:363-369. Epub 2015 Feb 21.

Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague, Czech Republic.

Polymers with functionalized surfaces have attracted a lot of attention in the last few years. Due to the progress in the techniques of polymer micro-patterning, miniaturized bioanalytical assays and biocompatible devices can be developed. In the presented work, we performed surface modification of polyethylene naphthalate (PEN) foil by an excimer laser beam through a photolithographic contact mask. The aim was to fabricate micro-patterned areas with surface functional groups available for localized covalent immobilization of biotin. It was found out that depending on the properties of the laser scans, a polymer surface exhibits different degrees of modification and as a consequence, different degrees of surface biotinylation can be achieved. Several affinity tests with optical detection of fluorescently labeled streptavidin were successfully performed on biotinylated micro-patterns of a PEN foil. The polymer surface properties were also evaluated by electrokinetic analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results have shown that PEN foils can be considered suitable substrates for construction of micro-patterned bioanalytical affinity assays.
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http://dx.doi.org/10.1016/j.colsurfb.2015.02.032DOI Listing
April 2015

Nano-structured and functionalized surfaces for cytocompatibility improvement and bactericidal action.

Biotechnol Adv 2015 Nov 14;33(6 Pt 2):1120-9. Epub 2015 Jan 14.

Department of Solid State Engineering, University of Chemistry and Technology Prague, Technická 5, Prague, Czech Republic. Electronic address:

The field of material surface modification with the aim of biomaterial construction involves several approaches of treatments that allow the preparation of materials, which positively influence adhesion of cells and their proliferation and thus aid and improve tissue formation. Modified materials have a surface composition and morphology intended to interact with biological systems and cellular functions. Not only surface chemistry has an effect on material biological response, surface structures of different morphology can be constructed to guide a desirable biological outcome. Nano-patterned material surfaces have been tested with the aim of how surface geometry and physical properties on a micro- and nano-scale can affect cellular response and influence cell adhesion and proliferation. Biological functionality of solid state substrates was significantly improved by the irradiation of material with plasma discharge or laser treatment. Commonly used "artificial" polymers (e.g. polyethylene (PE), polystyrene (PS), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN)) and biopolymers (e.g. Poly-l-Lactic acid (PLLA), polymethylpentene (PMP)) were treated with aim of biocompatibility improvement. The treatment of polymer/biopolymer substrates leads to formation of ripple or wrinkle-like structures, supported also with heat treatment or other subsequent surface processing. Several types of chemically different substances (e.g. metal or carbon nano-particles, proteins) were grafted onto material surfaces or built into material structures by different processes. Surface physico-chemical properties (e.g. chemistry, charge, morphology, wettability, electrical conductivity, optical and mechanical properties) of treated surfaces were determined. The enhancement of adhesion and proliferation of cells on modified substrates was investigated in vitro. Bactericidal action of noble metal nano-particles (e.g. Au, Ag) on polymers was characterized. The influence of metal nano-particle grafting by using metal nano-particle suspension prepared by "green" methods was determined. Micro- and nano-patterned surfaces can be constructed as tissue scaffolds with specific functions regarding cell adhesion and proliferation or potential biosensor applications.
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http://dx.doi.org/10.1016/j.biotechadv.2015.01.001DOI Listing
November 2015

Preparation of periodic surface structures on doped poly(methyl metacrylate) films by irradiation with KrF excimer laser.

Nanoscale Res Lett 2014 28;9(1):591. Epub 2014 Oct 28.

Department of Solid State Engineering, Institute of Chemical Technology, Prague 166 28, Czech Republic.

In this work, we describe laser modification of poly(methyl methacrylate) films doped with Fast Red ITR, followed by dopant exclusion from the bulk polymer. By this procedure, the polymer can be modified under extremely mild conditions. Creation of surface ordered structure was observed already after application of 15 pulses and 12 mJ cm(-2) fluence. Formation of grating begins in the hottest places and tends to form concentric semi-circles around them. The mechanism of surface ordered structure formation is attributed to polymer ablation, which is more pronounced in the place of higher light intensity. The smoothness of the underlying substrate plays a key role in the quality of surface ordered structure. Most regular grating structures were obtained on polymer films deposited on atomically 'flat' Si substrates. After laser patterning, the dopant was removed from the polymer by soaking the film in methanol.
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http://dx.doi.org/10.1186/1556-276X-9-591DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4215891PMC
November 2014

Grafting of bovine serum albumin proteins on plasma-modified polymers for potential application in tissue engineering.

Nanoscale Res Lett 2014 Apr 4;9(1):161. Epub 2014 Apr 4.

Department of Solid State Engineering, Institute of Chemical Technology Prague, Technicka 5, Prague 166 28, Czech Republic.

In this work, an influence of bovine serum albumin proteins grafting on the surface properties of plasma-treated polyethylene and poly-l-lactic acid was studied. The interaction of the vascular smooth muscle cells with the modified polymer surface was determined. The surface properties were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, nano-LC-ESI-Q-TOF mass spectrometry, electrokinetic analysis, and goniometry. One of the motivations for this work is the idea that by the interaction of the cell with substrate surface, the proteins will form an interlayer between the cell and the substrate. It was proven that when interacting with the plasma-treated high-density polyethylene and poly-l-lactic acid, the bovine serum albumin protein is grafted on the polymer surface. Since the proteins are bonded to the substrate surface, they can stimulate cell adhesion and proliferation.
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http://dx.doi.org/10.1186/1556-276X-9-161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3986457PMC
April 2014

Surface morphology and optical properties of porphyrin/Au and Au/porphyrin/Au systems.

Nanoscale Res Lett 2013 Dec 27;8(1):547. Epub 2013 Dec 27.

Department of Solid State Engineering, Institute of Chemical Technology, Prague 166 28, Czech Republic.

Porphyrin/Au and Au/porphyrin/Au systems were prepared by vacuum evaporation and vacuum sputtering onto glass substrate. The surface morphology of as-prepared systems and those subjected to annealing at 160°C was studied by optical microscopy, atomic force microscopy, and scanning electron microscopy techniques. Absorption and luminescence spectra of as-prepared and annealed samples were measured. Annealing leads to disintegration of the initially continuous gold layer and formation of gold nanoclusters. An amplification of Soret band magnitude was observed on the Au/meso-tetraphenyl porphyrin (TPP) system in comparison with mere TPP. Additional enhancement of luminescence was observed after the sample annealing. In the case of sandwich Au/porphyrin/Au structure, suppression of one of the two porphyrins' luminescence maxima and sufficient enhancement of the second one were observed.
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http://dx.doi.org/10.1186/1556-276X-8-547DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3884014PMC
December 2013

Ceramides in the skin lipid membranes: length matters.

Langmuir 2013 Dec 6;29(50):15624-33. Epub 2013 Dec 6.

Charles University in Prague , Faculty of Pharmacy, Heyrovského 1203, 50005 Hradec Králové, Czech Republic.

Ceramides are essential constituents of the skin barrier that allow humans to live on dry land. Reduced levels of ceramides have been associated with skin diseases, e.g., atopic dermatitis. However, the structural requirements and mechanisms of action of ceramides are not fully understood. Here, we report the effects of ceramide acyl chain length on the permeabilities and biophysics of lipid membranes composed of ceramides (or free sphingosine), fatty acids, cholesterol, and cholesterol sulfate. Short-chain ceramides increased the permeability of the lipid membranes compared to a long-chain ceramide with maxima at 4-6 carbons in the acyl. By a combination of differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, Langmuir monolayers, and atomic force microscopy, we found that the reason for this effect in short ceramides was a lower proportion of tight orthorhombic packing and phase separation of continuous short ceramide-enriched domains with shorter lamellar periodicity compared to native long ceramides. Thus, long acyl chains in ceramides are essential for the formation of tightly packed impermeable lipid lamellae. Moreover, the model skin lipid membranes are a valuable tool to study the relationships between the lipid structure and composition, lipid organization, and the membrane permeability.
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http://dx.doi.org/10.1021/la4037474DOI Listing
December 2013

Plasma treated polyethylene grafted with adhesive molecules for enhanced adhesion and growth of fibroblasts.

Mater Sci Eng C Mater Biol Appl 2013 Apr 11;33(3):1116-24. Epub 2012 Dec 11.

Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Technická 5, Prague 6, 166 28, Czech Republic.

The cell-material interface plays a crucial role in the interaction of cells with synthetic materials for biomedical use. The application of plasma for tailoring polymer surfaces is of abiding interest and holds a great promise in biomedicine. In this paper, we describe polyethylene (PE) surface tuning by Ar plasma irradiating and subsequent grafting of the chemically active PE surface with adhesive proteins or motives to support cell attachment. These simple modifications resulted in changed polymer surface hydrophilicity, roughness and morphology, which we thoroughly characterized. The effect of our modifications on adhesion and growth was tested in vitro using mouse embryonic fibroblasts (NIH 3T3 cell line). We demonstrate that the plasma treatment of PE had a positive effect on the adhesion, spreading, homogeneity of distribution and moderately on proliferation activity of NIH 3T3 cells. This effect was even more pronounced on PE coated with biomolecules.
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http://dx.doi.org/10.1016/j.msec.2012.12.003DOI Listing
April 2013

Gold nanolayer and nanocluster coatings induced by heat treatment and evaporation technique.

Nanoscale Res Lett 2013 May 22;8(1):249. Epub 2013 May 22.

Department of Solid State Engineering, Institute of Chemical Technology, Prague 166 28, Czech Republic.

The paper is focused on the preparation and surface characterization of gold coatings and nanostructures deposited on glass substrate. Different approaches for the layer preparation were applied. The gold was deposited on the glass with (i) room temperature, (ii) glass heated to 300°C, and (iii) the room temperature-deposited glass which was consequently annealed to 300°C. The sheet resistance and concentration of free carriers were determined by the van der Pauw method. Surface morphology was characterized using an atomic force microscopy. The optical properties of gold nanostructures were measured by UV-vis spectroscopy. The evaporation technique combined with simultaneous heating of the glass leads to change of the sheet resistance, surface roughness, and optical properties of gold nanostructures. The electrically continuous layers are formed for significantly higher thickness (18 nm), if the substrate is heated during evaporation process. The annealing process influences both the structure and optical properties of gold nanostructures. The elevated temperature of glass during evaporation amplifies the peak of plasmon resonance in the structures, the surface morphology being significantly altered.
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http://dx.doi.org/10.1186/1556-276X-8-249DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3663755PMC
May 2013