103 research outputs found
Electrospun magnetic composite poly-3-hydroxybutyrate/magnetite scaffolds for biomedical applications: composition, structure, magnetic properties, and biological performance
Magnetically responsive composite polymer scaffolds have good potential for a variety of biomedical applications. In this work, electrospun composite scaffolds made of polyhydroxybutyrate (PHB) and magnetite (Fe3O4) particles (MPs) were studied before and after degradation in either PBS or a lipase solution. MPs of different sizes with high saturation magnetization were synthesized by the coprecipitation method followed by coating with citric acid (CA). Nanosized MPs were prone to magnetite-maghemite phase transformation during scaffold fabrication, as revealed by Raman spectroscopy; however, for CA-functionalized nanoparticles, the main phase was found to be magnetite, with some traces of maghemite. Submicron MPs were resistant to the magnetite-maghemite phase transformation. MPs did not significantly affect the morphology and diameter of PHB fibers. The scaffolds containing CA-coated MPs lost 0.3 or 0.2% of mass in the lipase solution and PBS, respectively, whereas scaffolds doped with unmodified MPs showed no mass changes after 1 month of incubation in either medium. In all electrospun scaffolds, no alterations of the fiber morphology were observed. Possible mechanisms of the crystalline-lamellar-structure changes in hybrid PHB/Fe3O4 scaffolds during hydrolytic and enzymatic degradation are proposed. It was revealed that particle size and particle surface functionalization affect the mechanical properties of the hybrid scaffolds. The addition of unmodified MPs increased scaffolds' ultimate strength but reduced elongation at break after the biodegradation, whereas simultaneous increases in both parameters were observed for composite scaffolds doped with CA-coated MPs. The highest saturation magnetization-higher than that published in the literature-was registered for composite PHB scaffolds doped with submicron MPs. All PHB scaffolds proved to be biocompatible, and the ones doped with nanosized MPs yielded faster proliferation of rat mesenchymal stem cells. In addition, all electrospun scaffolds were able to support angiogenesis in vivo at 30 days after implantation in Wistar rats
Polyethylene/Polyhydroxyalkanoates-based Biocomposites and Bionanocomposites
The development of advanced polymer composite materials having superior
mechanical properties has opened up new horizons in the field of science and
engineering. Polyethylene (PE) is considered one of the most widely used thermoplastics
in the world due to its excellent properties which have excellent chemical
inertness, low coefficient of friction, toughness, near-zero moisture absorption,
ease of processing and electrical properties. Polyhydroxyalkanoates (PHAs) are
garnering increasing attention in the biodegradable polymer market because of
their promising properties such as high biodegradability in different environments.
This chapter covers polyethylene/polyhydroxyalkanoates-based biocomposites
and bionanocomposites. It summarizes many of the recent research accomplishments
in the area of PE/PHAs-based biocomposites and bionanocomposites such
as state-of-the-art regarding different methods of their preparation. Also discussed
are different characterization techniques and use of PE/PHAs-based biocomposites
and bionanocomposites in biomedical, packaging, structural, military,
coating, fire retardant, aerospace and optical applications, along with recycling
and lifetime studies
Growth of Mesenchymal Stem Cells on Poly(3-Hydroxybutyrate) Scaffolds Loaded with Simvastatin
ELECTRON-MICROSCOPIC STUDY OF CHANGES IN CEREBELLAR PYRIFORM NEURONS IN MICE WITH PROTEIN-CALORIC DEFICIENCY
Material-associated bone resorption
A number of similar macrophage responses to the implantation of various osteoplastic materials into bone defects in humans and laboratory animals have been demonstrated in the present article based on the retrospective analysis of the archival histological material (2008–2016). The presence of osteoplastic materials in a bone regenerate has led to the emergence of giant cells of foreign bodies and osteoclastogenic cells both on the surface of the material and neoformed bone with its subsequent resorption. It was suggested to name this phenomenon “material-associated bone resorption”. © 2019, Privolzhsky Research Medical University. All rights reserved
Effect of Poly(ethylene glycol) on the Ultrastructure and Physicochemical Properties of the Poly(3-hydroxybutyrate)
Influence of Cross-Linking on the Physical Properties and Cytotoxicity of Polyhydroxyalkanoate (PHA) Scaffolds for Tissue Engineering
ELECTRON-MICROSCOPIC STUDY OF CHANGES IN CEREBELLAR PYRIFORM NEURONS IN MICE WITH PROTEIN-CALORIC DEFICIENCY
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