Publications (3) View all
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Article: Modification of polylactide surfaces with lactide-ethylene oxide functional block copolymers: accessibility of functional groups.
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ABSTRACT: Feasibility of using amphiphilic block copolymers composed of polylactide (PLA) and poly(ethylene oxide) (PEO) blocks for biomimetic surface modification of polylactide-based biomaterials for tissue engineering was investigated. PEO-b-PLA copolymers were deposited on the PLA surface from a solution in PEO-selective solvent. Copolymers with a neutral omega-methoxy end group of the PEO block (mPEO-b-PLA) were used to provide hydrophilic surface of PLLA, which exhibited suppressed nonspecific protein adsorption. Their analogues, containing biotin group at the end of PEO block (bPEO-b-PLA), were used as a model of functional copolymers, carrying a biomimetic group, for example, a cell-adhesion fibronectine-derived peptide sequence. The surface topography of functional groups on the modified surface and their accessibility for interaction with a protein receptor was investigated, taking advantage of specific biotin-avidin interaction, on surfaces modified with a combination of mPEO-b-PLA and bPEO-b-PLA copolymers. The accessibility of model biotin groups for interaction with their protein counterpart was proven through visualization of avidin or avidin-labeled nanospheres with atomic force microscopy.Biomacromolecules 12/2009; 11(1):68-75. · 5.48 Impact Factor -
Article: Perivascular sirolimus-delivery system.
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ABSTRACT: Autologous vein grafts are often used for treating damaged vessels, e.g. arteriovenous fistulas or arterial bypass conduits. Veins have a different histological structure from arteries, which often leads to intimal hyperplasia and graft restenosis. The aim of this study was to develop a perivascular sirolimus-delivery system that would release the antiproliferative drug sirolimus in a controlled manner. Polyester Mesh I was coated with purasorb, i.e. a copolymer of L-lactide and ɛ-caprolactone, with dissolved sirolimus; Mesh II was coated with two copolymer layers; the layer with dissolved sirolimus was overlaid with pure purasorb. This arrangement allowed sirolimus to be released for 6 and 4 weeks, for Mesh I and Mesh II, respectively. Mesh II released sirolimus more homogeneously, without the initial burst effect during the first week. However, the cumulative release curve was steeper at later time points than the curve for Mesh I. Both meshes inhibited proliferation of rat vascular smooth muscle cells during 14-day culture in vitro and preserved excellent cell viability. Newly developed sirolimus-releasing perivascular meshes are promising devices for preventing autologous graft restenosis.International journal of pharmaceutics 11/2010; 404(1-2):94-101. · 2.96 Impact Factor -
Article: Adhesion and growth of vascular smooth muscle cells in cultures on bioactive RGD peptide-carrying polylactides.
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ABSTRACT: The surface of poly(L-lactide) (PLLA) films deposited on glass coverslips was modified with poly(DL-lactide) (PDLLA), or 1:4 mixtures of PDLLA and PDLLA-b-PEO block copolymers, in which either none, 5% or 20% of the copolymer molecules carried a synthetic extracellular matrix-derived ligand for integrin adhesion receptors, the GRGDSG oligopeptide, attached to the end of the PEO chain. The materials, perspective for vascular tissue engineering, were seeded with rat aortic smooth muscle cells (11,000 cells/cm(2)) and the adhesion, spreading, DNA synthesis and proliferation of these cells was followed on inert and bioactive surfaces. In 24-h-old cultures in serum-supplemented media, the number of cells adhering to the PDLLA-b-PEO copolymer was almost eight times lower than that on the control PDLLA surface. On the surfaces containing 5% and 20% GRGDSG-PEO-b-PDLLA copolymer, the number of cells increased 6- and 3-fold respectively, compared to the PDLLA-b-PEO copolymer alone. On PDLLA-b-PEO copolymer alone, the cells were typically round and non-spread, whereas on GRGDSG-modified surfaces the cell spreading areas approached those found on PDLLA, reaching values of 991 microm(2) and 611 microm(2) for 5% and 20% GRGDSG respectively, compared to 958 microm(2) for PDLLA. The cells on GRGDSG-grafted copolymers were able to form vinculin-containing focal adhesion plaques, to synthesize DNA and even proliferate in a serum-free medium, which indicates specific binding to the GRGDSG sequences through their adhesion receptors.Journal of Materials Science Materials in Medicine 08/2007; 18(7):1317-23. · 2.32 Impact Factor
