Biomedical subjects

V Svorcík

Publications and source records attributed to V Svorcík.

11 recordsLinked to original sources

PubMed2006

Structural, chemical and biological properties of carbon layers sputtered on polyethyleneterephtalate.

Carbon layers on polyethyleneterephtalate (PET) backing were prepared by sputtering from graphite target. UV-VIS, Raman spectroscopy, RBS (Rutherford backscattering) and ERDA (Elastic Recoil Detection Analysis) techniques were used for the characterization of the layers. Surface morphology of the layers was determined by AFM technique and the adhesion of 3T3 mouse fibroblasts on the layers was studied in vitro. It was found that the properties of the deposited carbon layer depend on the sputtering time. The concentration of conjugated double bonds, fraction of amorphous hydrogenated carbon (a-C:H) containing oxygen and surface roughness are increasing functions of the sputtering time. The changes of the layer surface morphology with increasing sputtering time were also observed. For the sputtering times up to 30' the number of adhering 3T3 cells increases with increasing sputtering time. For longer sputtering times, however, the cell adhesion becomes lower probably due to unfavorable changes in roughness and morphology of the layer.

3T3 Cells↗

PubMed2004

Cell adhesion on artificial materials for tissue engineering.

Advanced interdisciplinary scientific field of tissue engineering has been developed to meet increasing demand for safe, functional and easy available substitutes of irreversibly damaged tissues and organs. First biomaterials were constructed as "two-dimensional" (allowing cell adhesion only on their surface), and durable (non-biodegradable). In contrast, biomaterials of new generation are characterized by so-called three dimensional porous or scaffold-like architecture promoting attachment, growth and differentiation of cells inside the material, accompanied by its gradual removal and replacement with regenerated fully functional tissue. In order to control these processes, these materials are endowed with a defined spectrum of bioactive molecules, such as ligands for adhesion receptors on cells, functional parts of natural growth factors, hormones and enzymes or synthetic regulators of cell behavior, incorporated in defined concentrations and spatial distribution against a bioinert background resistant to uncontrolled protein adsorption and cell adhesion.

Animals↗

PubMed2003

Cell adhesion on polytetrafluoroethylene modified by UV-irradiation in an ammonia atmosphere.

We report on the modification of polytetrafluoroethylene (PTFE) by exposure to the ultraviolet (UV) light of a Xe(2)*-excimer lamp at a wavelength of 172 nm in an ammonia atmosphere. Typical treatment times were up to 30 min. Subsequently, the samples were grafted with the amino acid alanine from an aqueous solution. The samples were characterized by means of optical transmission spectroscopy, laser-induced fluorescence and contact-angle measurements. We studied the adhesion of rat aortic smooth muscle cells (SMC) and mouse fibroblasts (3T3 cells) to the modified polymer samples using an in vitro technique, where the population density and spread of adhering cells is determined 24 h after seeding by image analysis. For both cell types the exposure of PTFE to UV-light in an ammonia atmosphere resulted in a significant increase in the number of adhering cells and in the size of their spreading area. The grafting with alanine enhanced this effect. Additional experiments with human endothelial cells (HEC) also demonstrated improved adhesion to modified PTFE. Thus, PTFE modified by our method appears to be a promising material for fabrication of artificial vascular prostheses and implants or for cultivation of skin substitutes.

3T3 Cells↗

PubMed2002

Colonization of ion-modified polyethylene with vascular smooth muscle cells in vitro.

Polyethylene (PE) foils were implanted with 40 and 150 keV Ar+ ions to the fluences from 1 x 10(13) to 1 x 10(15) cm(-2). Production of conjugated double bonds, characterizing degradation of the PE surface layer, was studied using UV-VIS spectroscopy. Wettability of the PE surface, determined by conventional goniometric techniques, was shown to be an increasing function of both ion energy and fluence. It was also increased after exposure of PE to serum-supplemented cell culture media. Cell culture experiments showed that the ion irradiation significantly increased the adherence of vascular smooth muscle cells (VSMC) and their subsequent growth on the PE surface. On day 1 after seeding, the number of initially adhered VSMC exhibited two maxima. On day 3 after seeding. these maxima disappeared, which was partially due to a significantly shorter doubling time of VSMC. On the other ion-modified samples. the doubling time did not differ significantly from that on the unmodified PE. Enzyme-linked immunosorbent assay revealed increased concentration of talin, a protein of focal adhesion plaques, and alpha-actin, a marker of VSMC differentiation, in cells on ion-implanted surfaces. It can be concluded that the ion irradiation supports the adhesion and differentiation of VSMC without excessive proliferation of these cells.

Animals↗

PubMed2001

Adhesion and proliferation of rat vascular smooth muscle cells (VSMC) on polyethylene implanted with O+ and C+ ions.

Polyethylene was implanted with 30-keV oxygen (PE/O+) or 23-keV carbon ions (PE/C+) at 10(13) to 5 x 10(15) ions cm(-2) doses in order to improve the adhesion of vascular smooth muscle cell (VSMC) to the polymer surface in vitro because of its oxidation and carbon-enrichment. The concentration of -CO- groups in the PE/O+ and PE/C+ samples increased only up to doses of 3 x 10(14) and 10(15) ions cm(-2), respectively, and then declined. At the same time, the concentration of these groups, measured at a dose of 3 x 10(14) ions cm(-2), was higher in PE/O+ than in PE/C+ samples. Similarly, the number of initially-adhering rat VSMC (24 h after seeding) increased only up to a dose of 3 x 10(13) and 10(15) ions cm(-2) on PE/O+ and PE/C+ samples, respectively. In addition, between doses of 10(13) and 10(14) ions cm(-2), this number was about two to three times higher on PE/O+ samples. On the other hand, the surface wettability increased proportionally to the implanted ion dose, especially above a dose of 10(14) ions cm(-2). Thus, the number of initially-adhered cells appeared to be positively correlated with the amount of the oxygen group present at the polymer surface rather than with the surface wettability. The higher cell adhesion was accompanied by adsorption of fluorescent dye-conjugated collagen IV in larger amounts. The highest numbers of initially-adhered cells were usually associated with the lowest rates of subsequent proliferation (measured by the doubling time, BrdU labelling and M

Animals↗

PubMed2000

Fluorine ion-implanted polystyrene improves growth and viability of vascular smooth muscle cells in culture.

Vascular smooth muscle cells derived from the rat aorta were cultured on unmodified or F(+) ion-implanted polystyrene (5 x 10(12) or 5 x 10(14) ions/cm(2), energy 150 keV). In 1-day-old cultures, the cells adhered to the modified polystyrene in higher numbers and over larger contact areas. Increased resistance of the cells to trypsin-mediated detachment from the growth support indicated an improved adhesion of cells to the modified polymer at later culture intervals. The cells cultured on ion-modified polymers also were larger and had a higher total protein content. By use of immunocytochemistry, several specific protein species were increased, including the cytoskeletal alpha-actin and vimentin and the plasma membrane-associated vinculin, talin, alpha-v integrins, ICAM-1, and VCAM-1, which account for stronger cell-cell and cell-extracellular matrix adhesion. The lower number of cells found floating in the medium suggests that the spontaneous detachment of cells from the modified polystyrene was lower and that the viability of the adhered cell population was higher. As was shown by the two-parameter flow-cytometric measurements of BrdU incorporation and DNA content, as well as by (3)H-thymidine autoradiography, the cell proliferation on samples modified by the dose of 5 x 10(12) ions/cm(2) was similar to that in controls; and at the dose of 5 x 10(14) ions/cm(2), it tended to be even lower. The cells grown on the polymer implanted with the dose of 5 x 10(12) ions/cm(2) responded to a new artificially created cell-free area in a confluent cell layer by more intense migration whereas at the dose of 5 x 10(14) ions/cm(2), the migration ability of cells was similar to that on the unmodified polymer. The data revealed a higher biocompatibility of ion-implanted polystyrene with vascular smooth muscle cells in culture. There was better adhesion, differentiation, and survival, and there was neither excessive migration nor proliferation.

Animals↗

PubMed2000

Molecular mechanisms of improved adhesion and growth of an endothelial cell line cultured on polystyrene implanted with fluorine ions.

Endothelial cells derived from the bovine pulmonary artery (line CPAE, CCL 209, American Tissue Culture Collection, Rockville, MD, USA) were cultured on pristine or fluorine ion-irradiated polystyrene (5 x 10(12) or 5 x 10(14) F ions/cm2, 150 keV). At 24-h post-seeding interval, the number of cells which adhered to the ion-modified polystyrene was significantly higher than on the unmodified material (+20 and +58% in cultures with the polystyrene irradiated by lower and higher ion doses, respectively). On day 7, the populations cultured on the irradiated substrates grew to higher densities, exceeding the controls at the lower and higher ion doses by 69 and 180%, respectively. The cells on ion-implanted samples were also larger (+70-95% and +90-99% at the lower and higher ion doses, respectively) and contained more protein (+16% at both ion doses). As was shown by ELISA, the polystyrene irradiated by the higher ion dose enhanced the expression of a cytoskeletal protein, vimentin (+65%) and protein of focal adhesion plaques, talin (+15%). The content of integrin alpha5beta1 (VLA-5), receptor for fibronectin, was increased at both lower and higher ion doses (+22 and +57%). In contrast to this, the content of ICAM-1 and vinculin was similar in cells grown on both pristine and ion-irradiated growth substrates. Moreover, the expression of VCAM-1 and ELAM-1 was lower by 11-14% in both ion dose groups. The present study has shown that ion implantation of polymers improves the adhesion and growth of endothelial cells without elevating the expression of immunoglobulin and selectin types of adhesion molecules. This surface modification should promote colonization of an artificial vascular prosthesis by endothelial cells and make it less vulnerable by immune system cells of the recipient.

Animals↗

PubMed2000

Adhesion and proliferation of keratinocytes on ion beam modified polyethylene.

Polyethylene (PE) foils were modified by irradiation with Ar+ and Xe+ ions to different fluences and different physico-chemical properties of the irradiated PE were studied in relation to adhesion and proliferation of keratinocytes on the modified surface. Changes in the PE surface roughness were examined using the AFM technique, the production of conjugated double bonds and oxidized structures by UV-VIS and FTIR techniques respectively. The surface polarity was determined by measuring surface contact angle and two-point technique was used for the determination of PE sheet resistance. Adhesion and proliferation of keratinocytes was characterized using the MTT-test. The ion irradiation leads to creation of conjugated double bonds which, together with progressive carbonization, contribute to the observed decrease of sheet resistance. Oxidation of the irradiated PE surface layer during the ion implantation is observed. Besides oxidation, the PE surface polarity is affected by other factors. The observed increase of the PE surface roughness due to the ion irradiation is inversely proportional to the ion size. The adhesion and proliferation of keratinocytes on the ion irradiated PE is significantly higher than on the pristine PE. Distribution of results in keratinocyte cultivation and the number of cells is related to the ion fluence applied and to ion species as well.

Journal Article↗

PubMed1999

Growth and differentiation of the vascular smooth muscle and endothelial cells cultured on fluorine ion-implanted polystyrene.

The rat vascular (SMCs) and bovine endothelial cells (BECs) were cultured on conventional or fluorine ion-implanted polystyrene (5 x 10(12) and 5 x 10(14) fluorine ions/cm2). The cells grown on the implanted growth supports showed better adherence, higher volume and higher total protein content. The immunocytochemical analysis revealed that SMCs contained more of the cytoskeletal vimentin and the vascular SMC-specific alpha-actin as well as several cell adhesion-mediating molecules (vinculin, talin, alpha(v)-integrin and ICAM-1). In BECs, only the content of vimentin and talin increased, while expression of ICAM-1 was unchanged. The data suggest that cells on the ion implanted polymers could be more viable and that increased expression of some adhesion molecules mediating interactions with the host immune system is cell type-dependent.

Actins↗

PubMed1997

Structure and biocompatibility of ion beam modified polyethylene.

Structural changes of polyethylene (PE), induced by irradiation with 40 keV Ar+ ions at a fluence of 1x10(12)-1x10(15) cm(-2), are characterized by different experimental methods and physical parameters of the modified PE are related to its biocompatibility. Production of oxidized structures and conjugated double bonds in the PE surface layer modified by the ion irradiation was proved using IR, UV-VIS spectroscopies and a Rutherford backscattering technique. The fusion of macrophages onto implants made of as-irradiated and chemically doped PE was studied in vivo. It was found that the free surface energy is not a decisive factor affecting the non-self-recognition of the modified PE by macrophages. The fusion of macrophages, however, was found to be different on the as-irradiated specimens and the specimens additionally doped with acrylic acid.

Journal Article↗

PubMed1996

Adhesion and proliferation of cultured human aortic smooth muscle cells on polystyrene implanted with N+, F+ and Ar+ ions: correlation with polymer surface polarity and carbonization.

Physicochemical surface properties and biocompatibility were studied in polystyrene (PS) implanted with 150 keV N+, F+ and Ar+ at doses ranging from 1 x 10(12) to 1 x 10(15) cm-2. Adhesion and proliferation of cultured human aortic smooth muscle cells (SMCs) on ion implanted PS were thoroughly examined for dependence on implanted dose and ion species and in close relation to polymer surface oxidation, surface polarity, concentration of conjugated double bonds and sheet resistivity. The surface polarity of PS was a smooth, increasing function of the implanted dose. However, the dependence of SMC population density on the implanted dose was found to be more complicated. After 18 h cultivation time (i.e. when only cell attachment and spreading took place), the number of adhered SMCs and their degree of spreading first increased with increasing ion dose, and after reaching a maximum at the dose of 5 x 10(12) cm-2, they decreased to original values. For doses above 5 x 10(14) cm-2, an increase in SMC population density and spreading was again observed. The first maximum in cell adhesion can be explained by slight increases in the surface polarity and wettability, optimal for cell adhesion, and the second maximum by progressive carbonization of the PS surface. After 96 h cultivation time (i.e. when the cells proliferated intensively), the dramatic dependence of the SMC population density on implanted dose is mostly smeared out. This observed dependence of SMC attachment, spreading and subsequent proliferation on the implanted dose was similar in all three ion species, but highest cell densities were achieved on PS implanted with F+ ions.

Argon↗