Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Biological characterization of hydrogels of poly(vinyl alcohol) and hyaluronic acid (1994)
    Springer
    Journal of materials science 5 (1994), S. 613-616 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Hydrogels of hyaluronic acid (HA) and poly(vinyl alcohol) (PVA) were prepared using eight freezing-thawing cycles from HA/PVA blends (10/90, 20/80, 30/70, 40/60, 50/50, and 0/100 (w/w) ratios). The biocompatibility of the hydrogels was tested by means of in vitro cytotoxicity and cytocompatibility tests using cell culture techniques. The release with time of HA and PVA, the two hydrogel components, ion aqueous medium was also monitored and evaluated. The results indicate that all the hydrogels are not cytotoxic, while cell adhesion was very scarce in PVA and was not improved by the addition of HA. The release kinetics of HA and PVA from the hydrogels were different. After 2 h, HA percentages from about 80 (10/90 blend) to 100% (20/80, 40/60 blends) were released from the hydrogels into the aqueous medium. In contrast, the percentages of released PVA remain lower in time compared with HA, reaching a plateau after 24 h and ranging from a maximum of about 13% (0/100 blend) to a minimum of about 6% (10/90, and 20/80 blends).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00120341
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Poly(ester-ether-ester) block copolymers as biomaterials (1994)
    Springer
    Journal of materials science 5 (1994), S. 33-39 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Poly(ester-ether-ester) block copolymers, belonging to a class of biodegradable materials, were synthesized from poly(ethylene glycol) and ε-caprolactone by a simple ring-opening mechanism, which avoids the use of potentially toxic inorganic or organometallic initiators. The morphological and mechanical properties of such materials were investigated by gelpermeation chromatography, vapour pressure osmometry, proton magnetic resonance, infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry and stress-strain tensile tests. The biocompatibility was investigated by cytotoxicity and hemocompatibility tests; the cytotoxicity was tested by the Neutral Red uptake assay, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, the Kenacid Blue R-binding method, and by the cell proliferation test on polymer films; the hemocompatibility was tested by the contact activation both of the coagulation cascade (intrinsic pathway), by the plasma prekallikrein activation test, and of the thrombocytes, by measuring the release of platelet factor 4 and β-thromboglobulin. The experimental results show that such a polymerization process permits high-molecular mass block copolymers with relatively good tensile and mechanical properties to be obtained. Their cyto- and hemo-compatibility makes them suitable for employment as biomaterials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121151
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Degradation products of poly(ester-ether-ester) block copolymers do not alter endothelial metabolism in vitro (1995)
    Springer
    Journal of materials science 6 (1995), S. 824-828 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: In this paper we report experimental results from specific biocompatibility tests on two different classes of tri-block poly(ester-ether-ester) copolymers, namely copoly(ε-caprolactone-oxyethylene-ε-caprolactone) and copoly(L-lactide-oxyethylene-L-lactide). In particular, the human umbilical vein endothelial cells (HUVEC) metabolism has been studied in the presence both of the copolymers and of their hydrolytic breakdown products. The release of prostacyclin (PGl2) and angiotensin II (AII) has been measured at different times for copolymers with different composition and hydrophilicity. The results obtained seem to indicate that the block copolymers of both series do not alter the PGI2 and AII release by HUVEC populations in vitro. Similar results are found also after a prolonged contact between the cells and the hydrolytic breakdown products of the copolymers. Furthermore, some of the copolymers studied significantly stimulate the release of either PGI2 or AII. This finding might point towards the use of these copolymers as bioactive materials in the field of cardiovascular devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00134325
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Evaluation of poly(vinyl alcohol) hydrogels as a component of hybrid artificial tissues (1995)
    Springer
    Journal of materials science 6 (1995), S. 71-75 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Hydrogels are three-dimensional polymeric networks very similar to biological tissues. Many synthetic polymers can be used in preparing hydrogels. Among them poly(vinyl alcohol) (PVA), physically crosslinked by repeated freeze-thawing cycles of polymer aqueous solutions, is widely employed to make hydrogels for biomedical applications. To increase the similarity between hydrogels and natural tissues and to obtain “polymeric hybrid tissues”, we attempted to incorporate 3T3 cells, from a mouse fibroblast cell line, into PVA hydrogels obtained by one freeze-thawing cycle using as a solvent complete culture medium. Hydrogels were also made using eight freeze-thawing cycles from PVA solutions prepared using as a solvent either complete culture medium or water. Cell adhesion experiments were performed by seeding 3T3 and human umbilical vein endothelial cells (HUVEC) on to the hydrogel surface. The effect of the solvent and of the different number of freeze-thawing cycles on the mechanical characteristics of the PVA hydrogels were investigated by dynamic-mechanical techniques. A scanning force microscope analysis of the hydrogel surface viscoelastic properties was also carried out. Our results show that PVA is not cytotoxic. Although PVA hydrogel surface characteristics do not seem to favour the adhesion of substrate-dependent cells, encouraging results were obtained with the 3T3 cells incorporation. DMA analysis indicates that the networks prepared by eight freeze-thawing cycles possess a mechanical consistency comparable, even slightly better, than the ones prepared by only one freeze-thawing cycle and used for the cell incorporation studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00120410
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Block copolymers of L-lactide and poly(ethylene glycol) for biomedical applications (1994)
    Springer
    Journal of materials science 5 (1994), S. 308-313 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Poly (L-lactide)-poly (oxyethylene)-poly (L-lactide) block copolymers obtained in bulk, by a ring opening mechanism, from poly (ethylene glycol)s (PEG)s and L-lactide (LA), at 120–140°C, in the absence of added catalysts are described. By using PEGs with different molecular masses, 3000 and 35000, respectively, and varying the initial molar ratio LA to PEG, two series of copolymers with different molecular masses, relative length of blocks and hydrophilicity were obtained. Physico-chemical characterization of the copolymers had been previously performed. The morphological characteristics of the copolymers were investigated by means of X-ray diffractometry, optical and scanning electron microscopy. The biological properties of the materials were determined by evaluating their cytotoxicity, cytocompatibility, hemocompatibility and degradability using different standard tests. The results obtained indicate that the block copolymers synthesized may be useful for biomedical applications, in particular as resorbable drug vehicles. The materials are brittle and their mechanical properties are not appropriate for implant devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00058953
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...