Publications by authors named "Mehran Kasra"
Natural biopolymer-based hydrogels especially agarose and collagen gels, considering their biocompatibility with cells and their capacity to mimic biological tissues, have widely been used for in-vitro experiments and tissue engineering applications in recent years; nevertheless their mechanical properties are not always optimal for these purposes. Regarding the importance of the mechanical properties of hydrogels, many mechanical characterization studies have been carried out for such biopolymers. In this work, we have focused on understanding the mechanical role of agarose and collagen concentration on the hydrogel strength and elastic behavior.
View Article and Find Full Text PDFCardiomyocyte behavior on biodegradable polyurethane/gold nanocomposite scaffolds under electrical stimulation.
Mater Sci Eng C Mater Biol Appl
February 2016
Following a myocardial infarction (MI), cardiomyocytes are replaced by scar tissue, which decreases ventricular contractile function. Tissue engineering is a promising approach to regenerate such damaged cardiomyocyte tissue. Engineered cardiac patches can be fabricated by seeding a high density of cardiac cells onto a synthetic or natural porous polymer.
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- Gold nanotubes/nanowires (GNT/NW) were synthesized using a template-assisted technique and mixed with a castor oil-polyethylene glycol based polyurethane (PU) to create porous scaffolds for biomedical use, testing two concentrations: 100 and 50 ppm.* -
- The composite scaffolds were analyzed through various methods, including infrared spectroscopy and scanning electron microscopy, highlighting significant improvements in thermal and mechanical properties with the addition of GNT/NW, particularly at the 50 ppm concentration.* -
- Enhanced cell attachment and proliferation were observed in the 50 ppm GNT/NW composites due to hydrogen bonding with the PU matrix, leading to better surface properties compared to pure PU.*
Article Synopsis
- * Torsion tests were conducted on cylindrical bone samples from sheep, with some containing bone marrow and others without, across various strain rates.
- * The results showed that bone marrow presence did not significantly influence shear strength or modulus, while shear strength and modulus were found to be related to strain rate and apparent density, aiding in understanding bone failure mechanisms in trauma and implant interactions.
The pathogenesis of vibration-induced disorders of intervertebral disc at the cellular level is largely unknown. Dynamic loads with frequencies close to that of the in vivo human spine resonant frequency (4-6 Hz) have a destructive effect, which may induce extracellular disc matrix (ECM) degradation. To investigate this issue, three-dimensional (3D) alginate cultures of normal pig intervertebral disc nucleus and inner annulus cells were tested under dynamic hydrostatic loading.
View Article and Find Full Text PDFThe pathogenesis of vibration-induced disorders of intervertebral disc at the cellular level is largely unknown. The objective of this study was to establish a method to investigate the ranges of constructive and destructive hydrostatic loading frequencies and amplitudes in preventing or inducing extracellular disc matrix degradation. Using a hydraulic chamber, normal rabbit intervertebral disc cells were tested under dynamic hydrostatic loading.
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