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RISS 인기검색어
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- 저자 : Hamid Goodarzi (검색결과 3 건)
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Hamid Goodarzi,Sameereh Hashemi-Najafabadi,Nafiseh Baheiraei,Fatemeh Bagheri 한국조직공학과 재생의학회 2019 조직공학과 재생의학 Vol.16 No.3
BACKGROUND: Nowadays, production of nanocomposite scaffolds based on natural biopolymer, bioceramic, and metal ions is a growing field of research due to the potential for bone tissue engineering applications. METHODS: In this study, a nanocomposite scaffold for bone tissue engineering was successfully prepared using collagen (COL), beta-tricalcium phosphate (b-TCP) and strontium oxide (SrO). A composition of b-TCP (4.9 g) was prepared by doping with SrO (0.05 g). Biocompatible porous nanocomposite scaffolds were prepared by freeze-drying in different formulations [COL, COL/b-TCP (1:2 w/w), and COL/b-TCP-Sr (1:2 w/w)] to be used as a provisional matrix or scaffold for bone tissue engineering. The nanoparticles were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy and energy dispersive spectroscopy. Moreover, the prepared scaffolds were characterized by physicochemical properties, such as porosity, swelling ratio, biodegradation, mechanical properties, and biomineralization. RESULTS: All the scaffolds had a microporous structure with high porosity (* 95–99%) and appropriate pore size (100–200 lm). COL/b-TCP-Sr scaffolds had the compressive modulus (213.44 ± 0.47 kPa) higher than that of COL/b- TCP (33.14 ± 1.77 kPa). In vitro cytocompatibility, cell attachment and alkaline phosphatase (ALP) activity studies performed using rat bone marrow mesenchymal stem cells. Addition of b-TCP-Sr to collagen scaffolds increased ALP activity by 1.33–1.79 and 2.92–4.57 folds after 7 and 14 days of culture, respectively. CONCLUSION: In summary, it was found that the incorporation of Sr into the collagen-b-TCP scaffolds has a great potential for bone tissue engineering applications.
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Goodarzi, Amir R.,Akbari, Hamid R. Techno-Press 2014 Geomechanics & engineering Vol.7 No.2
The expansivity of clayey soils is a complicated phenomenon which may affect the stability of geotechnical structures and geo-environmental projects. In all common factors for the monitoring of soil expansion, less attention is given to anion type of pore space solutions. Therefore, this paper is concerned with the impact of various concentrations of different inorganic salts including NaCl, $Na_2SO_4$, and $Na_2CO_3$ on the macro and microstructure behavior of the expandable smectite clay. Comparison of the responses of the smectite/NaCl and smectite/$Na_2SO_4$ mixtures indicates that the effect of anion valance on the soil engineering properties is not very pronounced, regardless of the electrolyte concentration. However, at presence of carbonate as potential determining ions (PDIs) the swelling power increases up to 1.5 times compared to sulfate or chloride ions. The samples with $Na_2CO_3$ are also more deformable and show lower osmotic compressibility than the other mixtures. This demonstrates that the barrier performance of smectite greatly decreases in case of anions with the non-specific adsorption (e.g., $Cl^-$ and $SO{_4}^{2-}$) as the salinity of solution increases. Based on the results of the X-ray diffraction and sedimentation tests, the high soil volumetric changes upon exposure to carbonate is attributed to an increase in the repulsive forces between smectite basic unit layers due to the PDI effect of $CO{_3}^{2-}$ and increasing the pH level which enhance the buffering capacity of smectite. The study concluded that the nature of anion through its influence on the re-arrangement of soil microstructure and osmotic phenomena governs the hydro-mechanical parameters of expansive clays. It seems not coinciding with the double layer theory of the Gouy-Chapman double layer model.
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Majid Salehi,Arian Ehtrami,Farshid Bastami,Saeed Farzamfar,Sepanta Hosseinpour,Hamid Vahedi,Ahmad Vaez,Mostafa Rahvar,Arash Goodarzi 한국섬유공학회 2019 Fibers and polymers Vol.20 No.3
Peripheral nerve injury is a serious challenge which influences 2.8 percent of trauma patients. Tissue engineeringof peripheral nerves mainly focuses on axonal regeneration via various nerve guides. The aim of this study is to evaluate a novel polyurethane (PU)/gelatin nanofibers (GNFs) conduit’s potential combination with resveratrol (RVT) for sciatic nerve regeneration in the rat. Platelet-rich plasma (PRP) was used as a carrier for RVT. Different tests like contact angle, tensile strength etc. was used to evaluate properties of PU/GNFs conduits. In addition, the electron microscopy, MTT assay, and DAPI staining revealed its compatibility with Schwann cells. 24 male Wistar rats were allocated into four groups (n=6) (1) PU/GNF/PRP/Schwann cell, 2) PU/GNF/Schwann cell/PRP/RVT, 3) Positive control, and 4) Negative control in order to assess sciatic functional index (SFI), hot plate latency, electromyographical (EMG), the percentage of wet weight-loss of gastrocnemius muscle and histopathological studies using hematoxylin-eosin staining. The results represented sciatic functional index (SFI), hot plate latency, electromyographical improved significantly in group 1 and 2 compared to the negative control group. Histopathological findings showed remarkable improvements in myelin sheath regeneration and fibers condition in group 1 and 2 compared to the negative control group. Group 2 showed more resemblance to the normal sciatic nerve, with well-arranged fibers and an intact myelin sheath. This study successfully applied PU/GNFs/PRP/RVT conduits as a potential biocompatible nerve guide with proper mechanical properties, biocompatibility, and biodegradability that enhanced injured sciatic nerve’s recovery rate.
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