Degradable zinc-based alloys with an appropriate corrosion rate are promising materials for the preparation of temporary orthopaedic implants. Previously, we prepared and characterised a novel Zn1.5Mg alloy. This paper is focused on the characterisation of this alloy after a surface pre-treatment, which should mimic processes occurring in vivo. The samples of the Zn1.5Mg alloy were immersed in a simulated body fluid (SBF) at 37°C for 14days in order to form a protective layer of corrosion products. Thereafter, these samples were used for the corrosion rate determination, an indirect in vitro cytotoxicity test, as well as for a direct contact test and were compared with the non-treated samples. The protective layer was characterized by SEM and its chemical composition was determined by EDS and XPS analysis. The corrosion rate was significantly decreased after the pre-incubation. The protective layer of corrosion products was rich in Ca and P. The pre-incubated samples exhibited increased cytocompatibility in the indirect test (metabolic activity of L929 cells was above 70%) and we also observed osteoblast-like cell growth directly on the samples during the contact tests. Thus, the pre-incubation in SBF leading to improved cytocompatibility could represent more appropriate model to in vivo testing.
- MeSH
- Cell Line MeSH
- Magnesium * chemistry pharmacology MeSH
- Corrosion MeSH
- Mice MeSH
- Osteoblasts cytology metabolism MeSH
- Alloys * chemistry pharmacology MeSH
- Body Fluids chemistry MeSH
- Materials Testing * MeSH
- Cell Survival drug effects MeSH
- Absorbable Implants * MeSH
- Zinc * chemistry pharmacology MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Suitable fluorophores are the core of fluorescence imaging. Among the most exciting, yet controversial, labels are quantum dots (QDs) with their unique optical and chemical properties, but also considerable toxicity. This hinders QDs applicability in living systems. Surface chemistry has a profound impact on biological behavior of QDs. This study describes a two-step synthesis of QDs formed by CdTe core doped with Schiff base ligand for lanthanides [Ln (Yb3+, Tb3+ and Gd3+)] as novel cytocompatible fluorophores. RESULTS: Microwave-assisted synthesis resulted in water-soluble nanocrystals with high colloidal and fluorescence stability with quantum yields of 40.9-58.0%. Despite induction of endocytosis and cytoplasm accumulation of Yb- and TbQDs, surface doping resulted in significant enhancement in cytocompatibility when compared to the un-doped CdTe QDs. Furthermore, only negligible antimigratory properties without triggering formation of reactive oxygen species were found, particularly for TbQDs. Ln-doped QDs did not cause observable hemolysis, adsorbed only a low degree of plasma proteins onto their surface and did not possess significant genotoxicity. To validate the applicability of Ln-doped QDs for in vitro visualization of receptor status of living cells, we performed a site-directed conjugation of antibodies towards immuno-labeling of clinically relevant target-human norepinephrine transporter (hNET), over-expressed in neuroendocrine tumors like neuroblastoma. Immuno-performance of modified TbQDs was successfully tested in distinct types of cells varying in hNET expression and also in neuroblastoma cells with hNET expression up-regulated by vorinostat. CONCLUSION: For the first time we show that Ln-doping of CdTe QDs can significantly alleviate their cytotoxic effects. The obtained results imply great potential of Ln-doped QDs as cytocompatible and stable fluorophores for various bio-labeling applications.
- MeSH
- Single-Cell Analysis methods MeSH
- Fluorescent Dyes toxicity MeSH
- Quantum Dots toxicity MeSH
- Lanthanoid Series Elements chemistry MeSH
- Humans MeSH
- Microwaves MeSH
- Cell Line, Tumor MeSH
- Optical Imaging methods MeSH
- Surface Properties MeSH
- Schiff Bases chemistry MeSH
- Cadmium Compounds toxicity MeSH
- Tellurium toxicity MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
INTRODUCTION: The study investigates the potential for producing medical components via Selective Laser Melting technology (SLM). The material tested consisted of the biocompatible titanium alloy Ti6Al4V. The research involved the testing of laboratory specimens produced using SLM technology both in vitro and for surface roughness. The aim of the research was to clarify whether SLM technology affects the cytocompatibility of implants and, thus, whether SLM implants provide suitable candidates for medical use following zero or minimum post-fabrication treatment. Areas covered: The specimens were tested with an osteoblast cell line and, subsequently, two post-treatment processes were compared: non-treated (as-fabricated) and glass-blasted. Interactions with MG-63 cells were evaluated by means of metabolic MTT assay and microscope techniques (scanning electron microscopy, fluorescence microscopy). Surface roughness was observed on both the non-treated and glass-blasted SLM specimens. Expert Commentary: The research concluded that the glass-blasting of SLM Ti6Al4V significantly reduces surface roughness. The arithmetic mean roughness Ra was calculated at 3.4 µm for the glass-blasted and 13.3 µm for the non-treated surfaces. However, the results of in vitro testing revealed that the non-treated surface was better suited to cell growth.
- MeSH
- Cell Line MeSH
- Lasers * MeSH
- Humans MeSH
- Osteoblasts cytology metabolism MeSH
- Surface Properties MeSH
- Materials Testing * MeSH
- Titanium pharmacology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Novel composite films combining biocompatible polysaccharides with conducting polyaniline (PANI) were prepared via the in-situ polymerization of aniline hydrochloride in the presence of sodium hyaluronate (SH) or chitosan (CH). The composite films possess very good cytocompatibility in terms of adhesion and proliferation of two lines of human induced pluripotent stem cells (hiPSC). Moreover, the cardiomyogenesis and even formation of beating clusters were successfully induced on the films. The proportion of formed cardiomyocytes demonstrated excellent properties of composites for tissue engineering of stimuli-responsive tissues. The testing also demonstrated antibacterial activity of the films against E. coli and PANI-SH was able to reduce bacterial growth from 2 × 105 to < 1 cfu cm-2. Physicochemical characterization revealed that the presence of polysaccharides did not notably influence conductivities of the composites being ∼1 and ∼2 S cm-1 for PANI-SH and PANI-CH respectively; however, in comparison with neat PANI, it modified their topography making the films smoother with mean surface roughness of 4 (PANI-SH) and 14 nm (PANI-CH). The combination of conductivity, antibacterial activity and mainly cytocompatibility with hiPSC opens wide application potential of these polysaccharide-based composites.
- MeSH
- Aniline Compounds chemistry MeSH
- Anti-Bacterial Agents chemistry pharmacology MeSH
- Biocompatible Materials chemistry pharmacology MeSH
- Cell Adhesion drug effects MeSH
- Cell Line MeSH
- Chitosan chemistry MeSH
- Electric Conductivity MeSH
- Escherichia coli drug effects MeSH
- Induced Pluripotent Stem Cells drug effects metabolism MeSH
- Hyaluronic Acid chemistry MeSH
- Humans MeSH
- Nanocomposites chemistry MeSH
- Polymerization MeSH
- Surface Properties MeSH
- Cell Proliferation drug effects MeSH
- Staphylococcus aureus drug effects MeSH
- Tissue Engineering methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
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.
The aim of this study was to develop an osteo-inductive resorbable layer allowing the controlled elution of antibiotics to be used as a bone/implant bioactive interface particularly in the case of prosthetic joint infections, or as a preventative procedure with respect to primary joint replacement at a potentially infected site. An evaluation was performed of the vancomycin release kinetics, antimicrobial efficiency and cytocompatibility of collagen/hydroxyapatite layers containing vancomycin prepared employing different hydroxyapatite concentrations. Collagen layers with various levels of porosity and structure were prepared using three different methods: by means of the lyophilisation and electrospinning of dispersions with 0, 5 and 15wt% of hydroxyapatite and 10wt% of vancomycin, and by means of the electrospinning of dispersions with 0, 5 and 15wt% of hydroxyapatite followed by impregnation with 10wt% of vancomycin. The maximum concentration of the released active form of vancomycin characterised by means of HPLC was achieved via the vancomycin impregnation of the electrospun layers, whereas the lowest concentration was determined for those layers electrospun directly from a collagen solution containing vancomycin. Agar diffusion testing revealed that the electrospun impregnated layers exhibited the highest level of activity. It was determined that modification using hydroxyapatite exerts no strong effect on vancomycin evolution. All the tested samples exhibited sufficient cytocompatibility with no indication of cytotoxic effects using human osteoblastic cells in direct contact with the layers or in 24-hour infusions thereof. The results herein suggest that nano-structured collagen-hydroxyapatite layers impregnated with vancomycin following cross-linking provide suitable candidates for use as local drug delivery carriers.
- MeSH
- Anti-Bacterial Agents * administration & dosage chemistry MeSH
- Durapatite * administration & dosage chemistry MeSH
- Collagen * administration & dosage chemistry MeSH
- Plasma chemistry MeSH
- Drug Delivery Systems * MeSH
- Humans MeSH
- Cell Line, Tumor MeSH
- Nanostructures administration & dosage chemistry MeSH
- Osteoblasts drug effects MeSH
- Staphylococcus aureus drug effects MeSH
- Staphylococcus epidermidis drug effects MeSH
- Vancomycin * administration & dosage chemistry MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
The application of biodegradable magnesium-based materials in the biomedical field is highly restricted by their low fatigue strength and high corrosion rate in biological environments. Herein, we treated the surface of a biocompatible magnesium alloy AZ31 by severe shot peening in order to evaluate the potential of surface grain refinement to enhance this alloy's functionality in a biological environment. The AZ31 samples were studied in terms of micro/nanostructural, mechanical, and chemical characteristics in addition to cytocompatibility properties. The evolution of surface grain structure and surface morphology were investigated using optical, scanning and transmission electron microscopy. Surface roughness, wettability, and chemical composition, as well as in depth-microhardness and residual stress distribution, fatigue behaviour and corrosion resistance were investigated. Cytocompatibility tests with osteoblasts (bone forming cells) were performed using sample extracts. The results revealed for the first time that severe shot peening can significantly enhance mechanical properties of AZ31 without causing adverse effects on the growth of surrounding osteoblasts. The corrosion behavior, on the other hand, was not improved; nevertheless, removing the rough surface layer with a high density of crystallographic lattice defects, without removing the entire nanocrystallized layer, provided a good potential for improving corrosion characteristics after severe shot peening and thus, this method should be studied for a wide range of orthopedic applications in which biodegradable magnesium is used. STATEMENT OF SIGNIFICANCE: A major challenge for most commonly used metals for bio-implants is their non-biodegradability that necessitates revision surgery for implant retrieval when used as fixation plates, screws, etc. Magnesium is reported among the most biocompatible metals that resorb over time without adverse tissue reactions and is indispensable for many biochemical processes in human body. However, fast and uncontrolled degradation of magnesium alloys in the physiological environment in addition to their inadequate mechanical properties especially under repeated loading have limited their application in the biomedical field. The present study providesdata on the effect of a relatively simple surface nanocrystallziation method with high potential to tailor the mechanical and chemical behavior of magnesium based material while maintaining its cytocompatibility.
- MeSH
- Electrochemistry MeSH
- Corrosion MeSH
- Cells, Cultured MeSH
- Humans MeSH
- Nanostructures chemistry ultrastructure MeSH
- Osteoblasts cytology drug effects MeSH
- Surface Properties MeSH
- Alloys pharmacology MeSH
- Materials Testing methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The aim of this study was to develop a biodegradable nanostructured electrospun layer based on collagen (COL), hydroxyapatite nanoparticles (HA), vancomycin hydrochloride (V), gentamicin sulphate (G) and their combination (VG) for the treatment of prosthetic joint infections and the prevention of infection during the joint replacement procedure. COL/HA layers containing different amounts of HA (0, 5 and 15 wt%) were tested for the in vitro release kinetics of antibiotics, antimicrobial activity against MRSA, gentamicin-resistant Staphylococcus epidermidis and Enterococcus faecalis isolates and cytocompatibility using SAOS-2 bone-like cells. The results revealed that the COL/HA layers released high concentrations of vancomycin and gentamicin for 21 days and performed effectively against the tested clinically-relevant bacterial isolates. The presence of HA in the collagen layers was found not to affect the release kinetics of the vancomycin from the layers loaded only with vancomycin or its combination with gentamicin. Conversely, the presence of HA slowed down the release of gentamicin from the COL/HA layers loaded with gentamicin and its combination with vancomycin. The combination of both antibiotics exerted a positive effect on the prolongation of the conversion of vancomycin into its degradation products. All the layers tested with different antibiotics exhibited potential antibacterial activity with respect to both the tested staphylococci isolates and enterococci. The complemental effect of vancomycin was determined against both gentamicin-resistant Staphylococcus epidermidis and Enterococcus faecalis in contrast to the application of gentamicin as a single agent. This combination was also found to be more effective against MRSA than is vancomycin as a single agent. Importantly, this combination of vancomycin and gentamicin in the COL/HA layers exhibited sufficient cytocompatibility to SAOS-2, which was independent of the HA content. Conversely, only gentamicin caused the death of SAOS-2 independently of HA content and only vancomycin stimulated SAOS-2 behaviour with an increased concentration of HA in the COL/HA layers. In conclusion, COL/HA layers with 15 wt% of HA impregnated with vancomycin or with a combination of vancomycin and gentamicin offer a promising treatment approach and the potential to prevent infection during the joint replacement procedures.
- MeSH
- Anti-Bacterial Agents chemistry pharmacology MeSH
- Cell Line MeSH
- Enterococcus faecalis drug effects MeSH
- Gentamicins chemistry pharmacology MeSH
- Durapatite chemistry MeSH
- Prosthesis-Related Infections microbiology prevention & control MeSH
- Kinetics MeSH
- Collagen chemistry MeSH
- Bone Cements chemistry MeSH
- Humans MeSH
- Methicillin-Resistant Staphylococcus aureus drug effects MeSH
- Microbial Sensitivity Tests methods MeSH
- Staphylococcus epidermidis drug effects MeSH
- Drug Synergism MeSH
- Vancomycin chemistry pharmacology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
We have investigated the application of Ar plasma for creation of nanostructured ultra high molecular weight polyethylene (PE) surface in order to enhance adhesion of mouse embryonic fibroblasts (L929). The aim of this study was to investigate the effect of the interface between plasma-treated and gold-coated PE on adhesion and spreading of cells. The surface properties of pristine samples and its modified counterparts were studied by different experimental techniques (gravimetry, goniometry and X-ray photoelectron spectroscopy (XPS), electrokinetic analysis), which were used for characterization of treated and sputtered layers, polarity and surface chemical structure, respectively. Further, atomic force microscopy (AFM) was employed to study the surface morphology and roughness. Biological responses of cells seeded on PE samples were evaluated in terms of cell adhesion, spreading, morphology and proliferation. Detailed cell morphology and intercellular connections were followed by scanning electron microscopy (SEM). As it was expected the thickness of a deposited gold film was an increasing function of the sputtering time. Despite the fact that plasma treatment proceeded in inert plasma, oxidized degradation products were formed on the PE surface which would contribute to increased hydrophilicity (wettability) of the plasma treated polymer. The XPS method showed a decrease in carbon concentration with increasing plasma treatment. Cell adhesion measured on the interface between plasma treated and gold coated PE was inversely proportional to the thickness of a gold layer on a sample.
- MeSH
- Coated Materials, Biocompatible * chemistry pharmacology MeSH
- Cell Line MeSH
- Mice MeSH
- Plasma Gases chemistry MeSH
- Polyethylenes * chemistry pharmacology MeSH
- Surface Properties MeSH
- Materials Testing * MeSH
- Gold * chemistry pharmacology MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Úvod a cíl: Oxidické vrstvy na povrchu titanové slitiny mají vliv na odolnost proti korozi a biokompatibilitu. Vynikající kompatibilita mezi tkání, kostí a slitinou titanu je převážně řízena vlastnostmi jeho stabilní povrchové vrstvy složené z oxidu titaničitého. Oxidové vrstvy mohou být připraveny mnoha různými metodami; oxidační proces a jeho podmínky vedou k různým vrstvám: rozdíly jsou v chemickém složení, mechanických vlastnostech, struktuře atd. Odchylka ve struktuře vrstvy může ovlivnit stabilitu, přilnavost nebo biokompatibilitu vrstvy. Anodická oxidace titanových slitin ve vhodném médiu (a za určitého napětí a proudové hustoty) může vytvořit nejen oxidickou vrstvu, ale také strukturu na povrchu oxidické vrstvy. Tato struktura je obvykle charakterizována póry o velikosti od desítek do stovek nanometrů. Strukturovaný povrch radikálně mění interakci mezi povrchem titanu a buňkami, a tím i chování tohoto materiálu uvnitř těla. Chování buněk na strukturovaném povrchu různých slitin titanu není dosud řádně popsáno. Tato experimentální práce povede k lepšímu pochopení těchto strukturovaných oxidových vrstev. Metody: Anodická oxidace byla provedena na vyleštěných vzorcích z Ti6Al4V ELI. Oxidační proces probíhal v elektrolytu 1M H2SO4 s napětím kolem 100 V a proudovou hustotou 50 mA/cm2. Výsledná oxidická vrstva byla hodnocena a dokumentována pomocí řádkovací elektronové mikroskopie (SEM), kterou byla kontrolována tloušťka oxidické vrstvy a povrchová morfologie. Pozorována byla také změna zbarvení a drsnosti povrchové vrstvy po oxidaci související s růstem oxidů. Cytokompatibilita povrchu materiálu je vyjádřena stanovením plochy povrchu, kterou obsadí buňky po třídenní kultivaci. Jedná se o metodu, která je běžně užívána a akreditována Českým institutem pro akreditaci. K pokusu byly užity buňky MG63 a bylo stanoveno procento buňkami kolonizované plochy povrchu. Hodnocení bylo provedeno na leštěných a anodizovaných površích vzorků z Ti6Al4V ELI. Výsledky byly navzájem porovnány. Výsledky: Byly připraveny vzorky s povrchem nanostrukturovaným pomocí anodické oxidace, přičemž struktura povrchu byla tvořena póry o velikostech v řádech desítek až stovek nanometrů. Výsledky pokusů ukázaly větší vůli buněk kolonizovat anodizovaný povrch. Neanodizovaný povrch byl kolonizován v 56,9 %, kdežto anodizovaný byl při stejných podmínkách kolonizován v 63,5 %. Všechny výběrové soubory byly gaussovsky distribuovány. Závěr: Anodickou oxidací byla připravena nanostrukturovaná oxidická vrstva na vzorcích z Ti6Al4V ELI. Cytokompatibilita vytvořené vrstvy byla porovnávána vůči neoxidovaným vzorkům. Bylo ukázáno, že buňky kolonizují větší plochu povrchu vzorku v případě oxidovaných vzorků.
Introduction, aim: The oxide layers on surface of titanium alloy are infl uencing corrosion resistance and biocompatibility. The compatibility between the bony tissue and titanium alloy is prevalently dependent on properties of a stable titanium dioxide layer. These layers can be prepared by various methods. The oxidation process (and its conditions) is resulting in diff erent types of oxide layer: diff erence in chemical composition, mechanical properties, inner structure etc. The deviation inside of the layers structure may infl uence the stability of the layer, its adhesion or biocompatibility. The anodic oxidation of titanium alloys in appropriate electrolyte (under certain conditions) can lead not only to creation of the oxide layer, but to creation of an oxide layer with structured surface. This kind of structure is usually characterized by pores in nanometer scale. The structured surface radically changes the interaction between the titanium alloys surface and cells; and thus influencing its behavior inside a body. The cell interaction with the structured surfaces is not properly described yet. This work aims for better understanding of such structured layers. Methods: The anodic oxidation was carried out on Ti6Al4V ELI polished samples. The oxidation process was realized in 1M H2SO4 electrolyte with the voltage 100 V and current density 50 mA/cm2. The thickness and surface morphology of the resulting oxide layer were evaluated and documented using a scanning electron microscope (SEM). The changes of color and roughness of the surface after the oxidation were observed as well. The cytocompatibility of the materials surface is expressed by a surface area colonized by cells after the three days of cultivation. This method is standardly used and accredited by ČIA. The MG63 cells were used for the experiment and the percentage of colonized surface area was evaluated. The evaluation was done on polished and oxidized Ti6Al4V ELI samples and the results were compared. Result: The structure of samples prepared using the anodic oxidation consisted of pores with size ranging from tens to hundreds of nanometers. The cytocompatibility testings showed that the cells colonized larger area on the oxidized samples. The cells covered 56.9% of the surface area of the polished samples, while 63.5% of the surface area of the anodized samples. Results of all samples exhibited Gaussian distribution. Conclusion: The anodic oxidation lead to a creation of nanostructured oxide layer on Ti6Al4V ELI samples. The cytocompatibility of this layer was compared to polished samples. It was shown that cells are colonizing the larger surface area on the oxidized samples.
- Keywords
- oxidická vrstva, cytokompatibilita, MG63, anodická oxidace,
- MeSH
- Biocompatible Materials * MeSH
- Cells MeSH
- Humans MeSH
- Titanium MeSH
- Research MeSH
- Check Tag
- Humans MeSH
