Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 51Citation - Scopus: 60Biosilica Incorporated 3d Porous Scaffolds for Bone Tissue Engineering Applications(Elsevier Ltd., 2018) Tamburacı, Sedef; Tıhmınlıoğlu, FundaAs a natural and abundant silica mineral, diatomite particles (SiO2-nH2O) have been used in several areas such as filtration, photonics, sound and heat insulation, filler material and drug delivery due to its abundance, inexpensive cost, unique morphology and porous structure. But up to date, diatomite incorporated silica based scaffolds have not been used for bone tissue engineering applications. In the present study, the goal was to combine the useful biomaterial properties of both chitosan and diatomite as biocomposite organic/inorganic biomaterial for bone tissue engineering applications and optimize the silica content of the composites in order to obtain optimum morphological structure, high mechanical properties, enlarged surface area and enhanced cell proliferation. The effect of silica loading on the mechanical, morphological, chemical, and surface properties, wettability and biocompatibility of composite scaffolds were investigated. In addition, in vitro cytotoxicity and cellular activities including cell proliferation, ALP activity and biomineralization were investigated in order to determine biological activity of the composite scaffolds. Diatomite particles lead to enhancement in the water uptake capacity of scaffolds. Chitosan-silica composites exhibited 82–90% porosity. Wet chitosan-silica composite scaffolds exhibited higher compression moduli when compared to pure chitosan scaffold in the range of 67.3–90.1 kPa. Average pore size range of chitosan-diatomite composite scaffolds was obtained as 218-319 μm. In vitro results indicated that chitosan-diatomite composites did not show any cytotoxic effect on 3T3, MG-63 and Saos-2 cell lines. Scaffolds were found to be favorable for osteoblast proliferation. Diatomite incorporation showed promising effects on enhancing ALP activity as well as mineral formation on scaffold surface. Thus, the prepared scaffolds in this study can be considered prospective material for bone tissue engineering applications.Article Citation - WoS: 16Citation - Scopus: 19Designing of Spherical Chitosan Nano-Shells With Micellar Cores for Solvation and Safeguarded Delivery of Strongly Lipophilic Drugs(Elsevier Ltd., 2017) Cihan, Esra; Polat, Mehmet; Polat, HürriyetChitosan is a very effective biopolymer for drug delivery purposes due to its biocompatibility, positive charge and exceptionally pH sensitive degradability behavior in an aqueous medium. Nevertheless, its inability for dissolving lipophilic drug active material and the difficulties in controlling the size and shape of the synthesized particles in nanometer range are critical drawbacks in its effective use. In this study, a synthesis procedure which addresses both issues simultaneously is presented. The procedure is based on initial dissolution of lipophilic drug molecules within the hydrophobic cores of the micelles of a bio-compatible block-copolymer by ionic gelation and subsequent formation of a chitosan shell by polymerization around the micellar structures. Well-formed, hollow and perfectly spherical chitosan particles (nano-shells) in the 30–300 nm size range could be successfully manufactured. Characterization by STEM, TEM, AFM, FTIR and DLS, DLS-LDV techniques showed clearly that the drug was successfully incorporated into the chitosan structure. It was demonstrated that the particles enveloped the micelle(s) of a Pluronic copolymer (P-123) whose hydrophobic cores contained a strongly hydrophobic drug Probucol. The chitosan nano-shells are expected to act as an agent protecting the integrity of the drug-loaded micelles in the body fluid while providing a pH sensitive release medium. The drug uptake by the chitosan particles was very high. A very sharp increase in the amount of the drug released with a slight change in the acidity of the medium was an indication of the potential of the manufactured chitosan nano-shells as pH sensitive, target specific delivery vehicles for drug release.Article Citation - WoS: 96Citation - Scopus: 113Hypericum Perforatum Incorporated Chitosan Films as Potential Bioactive Wound Dressing Material(Elsevier Ltd., 2017) Güneş, Seda; Tıhmınlıoğlu, FundaRecent studies in wound dressing applications offer new therapies and promote wound healing process. The aim of this study was to develop Hypericum perforatum (St John's Wort) oil incorporated chitosan films for wound dressing applications. H. perforatum oil as a potential therapeutic agent was encapsulated in chitosan film to achieve a better wound dressing material. Oil incorporated chitosan films were successfully prepared by solvent casting method in different oil concentrations (0.25–1.5%v/v). Water vapor permeability (WVP), mechanical test, swelling behavior and surface hydrophobicity were performed in order to characterize the prepared films. Antimicrobial test was performed by disc diffusion method and the growth inhibition effects of the films including different amount of H. perforatum oil were investigated on Escherichia coli and Staphylococcus aureus. WVP increased with oil incorporation and the highest value was obtained for 0.25% oil concentration.The highest strain value was obtained in 0.25% oil content films although tensile stress decreased with increasing oil content. H. perforatum oil incorporated films had antimicrobial effect on both microorganisms. Chitosan based films had no cytotoxic effects on NIH3T3fibroblast cells and provided a good surface for cell attachment and proliferation. The results showed that the H. perforatum incorporated chitosan films seems to be a potential and novel biomaterial for wound healing applications.