Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 10Citation - Scopus: 12Enhanced Model Protein Adsorption of Nanoparticulate Hydroxyapatite Thin Films on Silk Sericin and Fibroin Surfaces(Springer, 2022) Özcan, Selçuk; Çiftçioğlu, MuhsinHydroxyapatite coated metallic implants favorably combine the required biocompatibility with the mechanical properties. As an alternative to the industrial coating method of plasma spraying with inherently potential deleterious effects, sol-gel methods have attracted much attention. In this study, the effects of intermediate silk fibroin and silk sericin layers on the protein adsorption capacity of hydroxyapatite films formed by a particulate sol-gel method were determined experimentally. The preparation of the layered silk protein/hydroxyapatite structures on glass substrates, and the effects of the underlying silk proteins on the topography of the hydroxyapatite coatings were described. The topography of the hydroxyapatite layer fabricated on the silk sericin was such that the hydroxyapatite particles were oriented forming an oriented crystalline surface. The model protein (bovine serum albumin) adsorption increased to 2.62 µg/cm2 on the latter surface as compared to 1.37 µg/cm2 of hydroxyapatite on glass without an intermediate silk sericin layer. [Figure not available: see fulltext.].Article Citation - WoS: 3Citation - Scopus: 3Particulate Sol Route Hydroxyapatite Thin Film-Silk Protein Interface Interactions(Gazi Üniversitesi, 2010) Özcan, Selçuk; Çiftçioğlu, MuhsinHydroxyapatite (HAp) thin film coatings were prepared on bioinert glass slides by a particulate sol method and the effects of intermediate silk fibroin and silk sericin coatings on the HAp film formation and surface topography were examined. The films prepared with smaller crushed particle sols had a higher agglomeration tendency during the drying consolidation step of the thin film formation, and contained agglomerates larger in number and size, which was demonstrated experimentally and in accordance with the DLVO theory. In the thin films prepared on intermediate sericin and fibroin films the number and size of agglomerates were decisively reduced, forming homogeneous films of predominantly primary particles, especially for the larger particle size sols. The regular surface electrostatic potential arrangements of the β-sheet structures of the sericin and fibroin, and of hydroxyapatite crystals, gave rise to the coulombic attraction driven surface energy minimization, enhancing the hydroxyapatite thin film formation process. The positive degree of cooperativity in the hydroxyapatite particle deposition on the silk protein coatings was disrupted by the particle agglomeration tendency.Conference Object Citation - WoS: 8Citation - Scopus: 12Mechanical Properties of Hydroxyapatite Composites Reinforced With Hydroxyapatite Whiskers(Trans Tech Publications, 2004) Şimşek, Deniz; Çiftçioğlu, Rukiye; Güden, Mustafa; Çiftçioğlu, Muhsin; Harsa, Hayriye ŞebnemSintering and mechanical behavior of pure and hydroxyapatite (HA) whisker reinforced HA composites were investigated in this work. Pure and composite samples were prepared by using a commercial powder and whiskers prepared by molten salt synthesis. The dry-pressed samples were sintered in the 800 and 1300°C range. The effect of whisker-addition on the mechanical properties of HA was investigated through compression and hardness testing. Compressive strength and fracture strain were observed to increase by the addition of whiskers.Conference Object Citation - WoS: 10Citation - Scopus: 13Preparation and Characterization of Polylactide-Hydroxyapatite Biocomposites(Trans Tech Publications, 2004) Gültekin, Naz; Tıhmınlıoğlu, Funda; Çiftçioğlu, Rukiye; Çiftçioğlu, Muhsin; Harsa, Hayriye ŞebnemIn the present study, the preparation and characterization of polylactide-Hydroxyapatite(HA) composite films for biomedical applications have been studied. The effects of number of parameters such as polymer type, HA loading, surface modification and its concentration on the mechanical and microstructural properties of the composites were investigated. Poly-L-Lactide and 96/4 Poly(L-Lactide co D-Lactide) copolymer-HA composites containing 10-40 wt% HA particles have been prepared by solvent casting technique. The HA powder was synthesized by precipitation technique. Interfacial interactions between HA and polylactide polymer were modified to improve filler compatibility and mechanical properties of the composites by surface treatment of the HA with two different silane coupling agents; 3-aminopropyltriemoxysilane (AMPTES) and 3-mercaptopropyltrimethoxysilane (MPTMS) at three different concentrations(0.5-2 wt%). Silane treatment indicated improvements in the mechanical properties of the composites compared to the untreated HA loaded polylactide composites. Tensile test results showed that the maximum improvement in the mechanical properties of the composites was obtained for PLA composites containing 1 wt% aminofunctional silane treated HA and 0.5-wt% mercaptopropyltrimethoxy silane treated HA for PDLA composites. Scanning electron microscopy studies also revealed better dispersion of silane treated HA particles in the polymer matrix.