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- BSc, (2012-2016): Antibacterial and hydrophobic properties of Chitosan-58S bioactive glass nanocomposite coatings on TiO2 nanotube
Bacterial infection and insignificant osseointegration have been recognized as the main reasons of the failures of titanium based implants. The aim of this study was to apply titanium oxide nanotube (TNT) array on titanium using electrochemical anodization process as a more appropriate substrate for chitosan and chitosan-58S bioactive glass (BG) (58S-BG-Chitosan) nanocomposite coatings covered TNTs (TNT/Chiosan, TNT/58S-BG-Chitosan, respectively) through a conventional dip-coating process. Results showed that a TNT layer with average inner diameter of 82 ± 19 nm and wall’s thickness of 23 ± 9 nm was developed on titanium surface using electrochemical anodization process. Roughness and contact angle measurement showed that TNT with Ra = 449 nm had highest roughness and hydrophilicity which then reduced to 86 nm and 143 nm for TNT/Chitosan and TNT/58S-BG-Chitosan, respectively. In vitro bioactivity evaluation in simulated buffer fluid (SBF) solution and antibacterial activity assay predicted that TNT/58S-BG-Chitosan was superior in bone like apatite formation and antibacterial activity against both gram-positive and gram-negative bacteria compared to Ti, TNT and TNT/Chitosan samples, respectively. Results revealed the noticeable MG63 cell attachment and proliferation on TNT/58S-BG-Chitosan coating compared to those of uncoated TNTs. These results confirmed the positive effect of using TNT substrate for natural polymer coating on improved bioactivity of implant.
- MSc, (2016-2018): Synthesis and evaluation of Polyvinyl Alcohol-Chitosan-Polyvinyl Pyrrolidone nanocomposite membrane contains calcium peroxide nanoparticles for use in wound healing
Skin is the outer membrane of the human body and at the same time, the largest organ that has important functions; Skin could prevent from excessive water loss, entrance of microorganisms into the body. At the present time, one of the most important challenges is repair of skin wounds. Wound dressing is one of the cheapest, most affordable and the suitable method for wound healing. The purpose of this study was to design and characterize polyvinyl alcohol(PVA)-chitosan-poly (vinylpyrrolidone)(PVP) / calcium peroxide nanocomposite fibrouse membranes. At first, calcium peroxide nanoparticles was synthesized by chemical deposition method. Then PVA-chitosan-PVP fiber membrane was optimized based on mechanical properties, swelling and SEM image. Consequently, PVA-chitosan-PVP /calcium peroxide nanocomposite membrane was electrospinned and characterized. The effect of calcium peroxide concentration (5,10 and 15 wt%) on the structural, mechanical and biological properties of fibrous membrane was evaluated and the release of hydrogen peroxide from fibrous membrane was assessed. The results showed that calcium peroxide nanoparticles were in the range of 171 nm. The optimized PVA-chitosan-PVP fibers with volume ratio of 40-40-20 with fiber size at 123 ± 6,2 nm, approprate mechanical properties (Youngs modules = 28.8±8 MPa, Strain of break = 10% and tensile strength = 2.9 ± 1.2 MPa), degradability of 70 ± 2% by 14 days immersion in phosphate buffer solution and water absorption of 251.7% was selected for further study. The results showed that incorporation of 5%wt calcium peroxide nanoparticles in the fiber membrane resulted in enhanced the tensile strength of the fiber membrane (3.4 ± 2.3 MPa). All the membranes released hydrogen peroxide after 72h immersion in p-benzoquinone solution. By increasing calcium peroxide concentration, hydrogen peroxide release was increased significantly. Morever it was observed that increasing the amount of calcium peroxide up to 15%wt resulted in reduced cell viability due to significant release of hydrogen peroxide. In conclusion, the PVA-chitosan-PVP /calcium peroxide nanocomposite fibrous membrane containing 5-10% calcium peroxide could be a suitable candidate for wound healing.