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Fabrication and characterizations of hydrogels for cartilage repairKaur, Payal, Khaghani, Seyed A., Oluwadamilola, Agbabiaka, Khurshid, Z., Zafar, M.S., Mozafari, M., Youseffi, Mansour, Sefat, Farshid 26 September 2017 (has links)
Yes / Articular cartilage is a vascular tissue with limited repair capabilities, leaving an afflicted person in extreme pain. The tissue experiences numerous forces throughout its lifetime. This study focuses on development of a novel hydrogel composed of chitosan and β-glycerophosphate for articular cartilage repair. The aim of this study was to investigate the mechanical properties and swelling behaviour of a novel hydrogel composed of chitosan and β-glycerophosphate for cartilage repair. The mechanical properties were measured for compression forces. Mach-1 mechanical testing system was used to obtain storage and loss modulus for each hydrogel sample to achieve viscoelastic properties of fabricated hydrogels. Two swelling tests were carried out to compare water retaining capabilities of the samples. The hydrogel samples were made of five different concentrations of β-glycerophosphate cross-linked with chitosan. Each sample with different β-glycerophosphate concentration underwent sinusoidal compression forces at three different frequencies -0.1Hz, 0.316Hz and 1Hz. The result of mechanical testing was obtained as storage and loss modulus. Storage modulus represents the elastic component and loss modulus represents the viscosity of the samples. The results obtained for 1Hz were of interest because the knee experiences frequency of 1Hz during walking.
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Effect of TGF-β1 on water retention properties of healthy and osteoarthritic chondrocytesRaja, Tehmeena I., Khaghani, Seyed A., Zafar, M.S., Khurshid, Z., Mozafari, M., Youseffi, Mansour, Sefat, Farshid 08 June 2018 (has links)
Yes / Articular cartilage, a connective tissue, contains chondrocytes and glycosaminoglycans (GAGs) which aid in
water retention, providing the tissue with its magnificent ability to prevent friction, withstand loads and absorb
compressive shocks however, cartilage, does not have the ability to regenerate and repair. Osteoarthritis (OA) is
a progressive degenerative disease, which includes reduction of cartilage thickness between two bones in a joint,
causing painful bone-to-bone contact. OA affects over 8 million people in the UK alone. , and as the primary causes
are unknown, available treatments including surgical and non-surgical techniques which only reduce the symptoms
created by the disorder instead of providing a cure. This project focused on utilizing TGF-β1, a cytokine found in
elevated amounts in healthy cartilage when compared to degraded cartilage, in order to observe the effects of the
growth factor on both healthy and osteoarthritic chondrocytes. The healthy and the osteoarthritic chondrocytes were
cultured in two different media (DMEM with and without TGF- β1) before utilizing the SpectraMax M2/M2e
plate reader to observe and analyze the effect of TGF-β1 on water retention properties of cells. This has been
achieved by quantifying the GAG content using DMMB dye. Results showed that although TGF-β1 did displayed an
increase in glycosaminoglycan synthesis, the statistical increase was not vast enough for the alternative hypothesis to
be accepted; further experimentation with TGF-β1, alongside other cytokines within the growth factor family is
needed to perceive the true influence of the growth factor on un cured degenerative diseases. It was concluded that
both the healthy and osteoarthritic cells treated with TGF-β1 absorbed considerably more DMMB in comparison to
the cells, suggesting that TGF-β1 indeed works to aid in water retention. TGF-β1 is a key factor to be exploited when
constructing treatments for osteoarthritis
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Development of hydrodynamically engineered cartilage in response to insulin-like growth factor-1 and transforming growth factor-beta1: formation and role of a type I collagen-based fibrous capsuleYang, Yueh-Hsun 20 September 2013 (has links)
Articular cartilage which covers the surfaces of synovial joints is designed to allow smooth contact between long bones and to absorb shock induced during joint movement. Tissue engineering, a means of combining cells, biomaterials, bioreactors and bioactive agents to produce functional tissue replacements suitable for implantation, represents a potential long-term strategy for cartilage repair. The interplay between environmental factors, however, gives rise to complex culture conditions that influence the development of tissue-engineered constructs. A fibrous capsule that is composed of abundant type I collagen molecules and resembles fibrocartilage usually forms at the outer edge of neocartilage, yet the understanding of its modulation by environmental cues is still limited. Therefore, this dissertation was aimed to characterize the capsule formation, development and function through manipulation of biochemical parameters present in a hydrodynamic environment while a chemically reliable media preparation protocol for hydrodynamic cultivation of tissue-engineered cartilage was established. To this end, a novel wavy-wall bioreactor (WWB) that imparts turbulent flow-induced shear stress was employed as the model system and polyglycolic acid scaffolds seeded with bovine primary chondrocytes were cultivated under varied biochemical conditions.
The results demonstrated that tissue morphology, biochemical composition and mechanical strength of hydrodynamically engineered cartilage were maintained as the serum content decreased by 80% (from 10% to 2%). Transient exposure of the low-serum constructs to exogenous insulin-like growth factor-1 (IGF-1) or transforming growth factor-β1 (TGF-β1) further accelerated their development in comparison with continuous treatment with the same bioactive molecules. The process of the capsule formation was found to be activated and modulated by the concentration of serum which contains soluble factors that are able to induce fibrotic processes and the capsule development was further promoted by fluid shear stress. Moreover, the capsule formation in hydrodynamic cultures was identified as a potential biphasic process in response to concentrations of fibrosis-promoting molecules such as TGF-β. Comparison between the capsule-containing and the capsule-free constructs, both of which had comparable tissue properties and were produced by utilizing the WWB system in combination with IGF-1 and TGF-β1, respectively, showed that the presence of the fibrous capsule at the construct periphery effectively improved the ability of engineered cartilage to integrate with native cartilage tissues, but evidently compromised its tissue homogeneity.
Characterization of the fibrous capsule and elucidation of the conditions under which it is formed provide important insights for the development of tissue engineering strategies to fabricate clinically relevant cartilage tissue replacements that possess optimized tissue homogeneity and properties while retaining a minimal capsule thickness required to enhance tissue integration.
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