Myocardial infarction occurs because coronary arteries insufficiency is one of the major causes of mortality worldwide. Recent studies have shown that tissue engineering of myocardial tissue to regenerate infarcted tissue or engineering of the coronary artery may help overcome this problem. In the present research, gelatin and single-walled carbon nanotube were firstly administrated to physico-chemically and biologically modulate polyurethane nanofibers. Electrospinning, as versatile and effective technique for production of functional nanoscale fiber, was applied. Incorporation of both gelatin and SWNTs reduced mean diameter of nanofibrous scaffolds from 210 to 140 nm, which influenced on initial cell behavior. Possible interaction between gelatin and SWNTs with polyurethane chains was evaluated using FTIR and DSC techniques. Regarding the incorporation of both gelatin and SWNTs, it was found that hydrophilicity of nanofibrous scaffolds dramatically improved. Scaffold degradation profile was adjusted by incorporation of gelatin. Biomimetic mechanical properties of composite scaffolds like normal blood vessel were developed and SWNTs improved the Young modulus and ultimate strength of scaffolds up to 16.47 ± 0.5 and 23.73 ± 0.5 MPa, respectively. However, addition of gelatin increased elongation at break due to its softening effect. The incorporation of the SWNTs led to significant enhancement of electrical conductivity of the scaffolds. Biological evaluation using SEM and MTT assay demonstrated that nanofibrous surface was covered by confluent and dense layer of both myocardial myoblast and endothelial cells after 7 days of culture, which is crucial for cardiovascular tissue engineering. Results verified that the fabricated scaffolds could be effective for cardiovascular tissue engineering.

The dental tissue scaffold must provide a favorable surface for dental pulp stem cell attachment and proliferation. Employing nanohydroxyapatite (HA) and nanofluorohydroxyapatite (FHA) beside synthetic and organic polymer in favor of scaffolds would be used in bone and dental tissue engineering. In this research, nanoHA and FHA/chitosan scaffolds were synthesized by freeze-drying technique. Surface morphology, chemical composition and hydrophilicity have a great impact on initial cell attachment which will further affect the cell viability and proliferation which evaluated by SEM, XRD and contact angle measurement. Bioactivity of scaffolds was investigated by immersion in simulated body fluid (SBF) and cell proliferation assay. In freeze-drying technique percentage usage of hydroxyapatite could be risen up to 40% and shown better macro-mechanical and physical properties and bioactivity. According to obtained results by adding chitosan, contact angle was decreased by %54 and %37 for polycaprolactone (PCL)/HA and PCL/FHA scaffolds. In addition, addition of chitosan causes significant increase in the cell proliferation for PCL/HA and PCL/FHA up to 81% and 164%, respectively. These results indicate that PCL/FHA/chitosan scaffold represent a big potential for dental tissue engineering.

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In this study, a calcium phosphate scaffold of hydroxyapatite (HAp) and dicalcium phosphate dihydrate (DCPD) for application in osteoconductive and osteoinductive scaffolds was synthesized and characterized. The important note is that the prepared composites converted to HAp/tricalcium phosphate (TCP) after heat-treatment. This class of composites is interesting because porous HAp/TCP generally degrade more rapid than HAp due to the increased resorption rate of TCP. According to the obtained results, the values of elastic modulus, compressive strength and density of the samples reduced with increasing the percentage of the DCPD phase. It is worth mentioning that the mechanical properties of the prepared samples were near the natural compact bone. The samples were examined in vitro to confirm the apatite forming ability of the composites. Also, in vivo examination in a rabbit model was employed. After fully observation it was concluded that new bone formed on the pore walls, as osteoids and osteoclasts were evident two months postoperatively. Based on the obtained results, the prepared scaffolds seem to be a promising biomaterial for low weight bearing orthopaedic applications.

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