Tissue Engineering
Farnaz Ghorbani; Ali Zamanian; Hanie Noje Dehian
Volume 8, Issue 4 , February 2015, , Pages 399-409
Abstract
In this study, we fabricated 3-dimentional PLGA-gelatin scaffolds with aligned-oriented pores by freeze casting technique which is similar to Extra Cellular Matrix (ECM), and evaluated its effect on both physical and mechanical features. Dissolving synthetic (PLGA) and natural (Gelatin) polymers in common ...
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In this study, we fabricated 3-dimentional PLGA-gelatin scaffolds with aligned-oriented pores by freeze casting technique which is similar to Extra Cellular Matrix (ECM), and evaluated its effect on both physical and mechanical features. Dissolving synthetic (PLGA) and natural (Gelatin) polymers in common solvent was one of the strengths of this investigation. Scanning electron microscopy (SEM) micrographs indicated that scaffolds contained 95% interconnected pores with diameter about 50-400 µm in horizontal direction and 50-200 µm in vertical direction. Moreover, the results of mercury intrusion porosimetry represented diameter of pores in range of 100–300 µm. According to fourieres transform infrared (FTIR) spectrum there was no inappropriate interactions during processing. Additionally, mechanical analysis (3.2 MPa) of PLGA-gelatin constructs illustrated that polymeric scaffolds can withstand mechanical loads in freezing direction. Based on the water absorption (950%) and biodegradation results, samples can support cellular interactions and prevent their integrity during tissue regeneration. In brief, freeze casted PLGA-gelatin scaffolds can provide unidirectional matrix with desired physical and mechanical characters to regenerate lesions.
Biopolymers
Hadis Bandegani; Saeed Hesaraki; Masoud Alizadeh
Volume 3, Issue 2 , June 2009, , Pages 99-109
Abstract
The aim of the present paper is to investigate the effect of incorporating various amounts of strontium ions (0.19 - 2.23 wt%) into calcium sulfate bio ceramics on the physical, structural properties and in vitro bioactivity and compare these properties with those of a pure calcium sulfate dehydrate ...
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The aim of the present paper is to investigate the effect of incorporating various amounts of strontium ions (0.19 - 2.23 wt%) into calcium sulfate bio ceramics on the physical, structural properties and in vitro bioactivity and compare these properties with those of a pure calcium sulfate dehydrate (gypsum) as control. Strontium-doped gypsum (Sr-gypsum) was obtained by mixing calcium sulfate hemihydrates powder and solutions of strontium nitrate followed by washing the specimens with distilled water for the removal of residual salts. Gypsum was the only phase found in the composition of both pure and Sr-gypsum meanwhile a shift into lower diffraction angles was observed in the x-ray diffraction patterns of doped specimens. The Sr-doped sampled exhibited higher compressive strength and lower solubility than pure gypsum. Microstructure of all gypsum specimens had been composed of many rod-like small crystals entangled to each others with more elongation and higher thickness in the cases of Sr-gypsum. EDXA pattern of Sr-gypsum showed the presence of calcium and sulfur ions as the main elements of gypsum as well as slight amount of strontium ion. A continuous release of strontium was observed from the Sr-gypsum after soaking in simulated body fluid for 14 days. Proliferation rate of cultured osteoblasts and higher alkaline phosphatase activity on doped samples was better compared to pure gypsum.
Biopolymers
Ruhollah Mahdinavaz Maghdam; Hamid Mirzadeh; Morteza Daliri; Alireza Zare
Volume 1, Issue 1 , June 2007, , Pages 19-27
Abstract
Recently there are studies in developing new methods to increase bacterial adhesion onto polymeric surfaces that are used in biological application such as cell-based biosensors. In this study the surface of polyethylene terephthalate (PET) films were irradiated using CO2 and KrF excimer pulsed ...
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Recently there are studies in developing new methods to increase bacterial adhesion onto polymeric surfaces that are used in biological application such as cell-based biosensors. In this study the surface of polyethylene terephthalate (PET) films were irradiated using CO2 and KrF excimer pulsed lasers and adhesion behavior of Escherichia coli k-12 (E. coli K-12) bacteria onto the irradiated surfaces was studied in vitro. The changes in the surface properties due to laser irradiation were characterized by scanning electron microscopy (SEM) and contact angle measurement. The results showed that laser treatment changes surface morphology and surface hydrophilicity. The number of bacteria that were adhered onto the surfaces was quantitatively investigated by fluorescent staining, microscopic observations and counting through Image Proplus software. The results showed that the number of adhered E. coli K-12 bacteria onto the irradiated surfaces by both CO2 and KrF lasers in comparison with unmodified surfaces was increased.
