Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 43Citation - Scopus: 47Bioactive Diatomite and Poss Silica Cage Reinforced Chitosan/Na-carboxymethyl Cellulose Polyelectrolyte Scaffolds for Hard Tissue Regeneration(Elsevier, 2019) Tamburacı, Sedef; Kimna, Ceren; Tıhmınlıoğlu, FundaRecently, natural polymers are reinforced with silica particles for hard tissue engineering applications to induce bone regeneration. In this study, as two novel bioactive agents, effects of diatomite and polyhedral oligomeric silsesquioxanes (POSS) on chitosan (CS)/Na-carboxymethylcellulose (Na-CMC) polymer blend scaffolds are examined. In addition, the effect of silica reinforcements was compared with Si-substituted nano-hydroxyapatite (Si-Hap) particles. The morphology, physical and chemical structures of the scaffolds were characterized with SEM, liquid displacement, FT-IR, mechanical analysis, swelling and degradation studies. The particle size and the crystal structure of diatomite, POSS and Si-Hap particles were determined with DLS and XRD analyses. In vitro studies were performed to figure out the cytotoxicity, proliferation, ALP activity, osteocalcin production and biomineralization to demonstrate the promising use of natural silica particles in bone regeneration. Freeze-dried scaffolds showed 190-307 mu m pore size range and 61-70% porosity. Both inorganic reinforcements increased the mechanical strength, enhanced the water uptake capacity and fastened the degradation rate. The nanocomposite scaffolds did not show any cytotoxic effect and enhanced the surface mineralization in osteogenic medium. Thus, diatomite and POSS cage structures can be potential reinforcements for nanocomposite design in hard tissue engineering applications.Article Citation - WoS: 25Citation - Scopus: 33Novel Phytochemical Cissus Quadrangularis Extract-Loaded Chitosan/Na-carboxymethyl Cellulose-Based Scaffolds for Bone Regeneration(SAGE Publications, 2018) Tamburacı, Sedef; Kimna, Ceren; Tıhmınlıoğlu, FundaMedicinal plants are attracting considerable interest as a potential therapeutic agent for bone tissue regeneration. Cissus quadrangularis L. is also a medicinal plant known with its osteogenic activity. In this study, a phytochemical scaffold was produced by incorporating Cissus quadrangularis with chitosan/Na-carboxymethyl cellulose blend by lyophilization technique. The effect of Cissus quadrangularis loading on the mechanical, morphological, chemical, and degradation properties as well as in vitro cytotoxicity, cell proliferation, and differentiation of the composites was investigated. Scanning electron microscopy images showed that porous Cissus quadrangularis-loaded scaffolds were obtained with an average pore size of 148-209 mu m which is appropriate for bone regeneration. Cissus quadrangularis incorporation enhanced the compression modulus of scaffolds from 76 to 654 kPa. In vitro cell culture results indicated that Cissus quadrangularis/chitosan/Na-carboxymethyl cellulose scaffolds provided a favorable substrate for the osteoblast adhesion, proliferation, and mineralization. Results supported the osteoinductive property of the Cissus quadrangularis extract-incorporated scaffolds even without osteogenic media supplement. Cissus quadrangularis extract increased the alkaline phosphatase activity of the SaOS-2 cells on scaffolds on 7th and 14th days of incubation. The investigation of characterization and cell culture studies suggest that Cissus quadrangularis-loaded osteoinductive Cissus quadrangularis/chitosan/Na-carboxymethyl cellulose scaffold can serve as a potential biomaterial for bone tissue engineering applications.Article Citation - WoS: 46Citation - Scopus: 53Chitosan-Hybrid Poss Nanocomposites for Bone Regeneration: the Effect of Poss Nanocage on Surface, Morphology, Structure and in Vitro Bioactivity(Elsevier, 2020) Tamburacı, Sedef; Tıhmınlıoğlu, FundaPOSS, regarded as the smallest silica particle, is widely used as nanofiller in polymer systems. POSS-based nanocomposites are deduced as novel materials having potency for biomedical applications owing to the enhanced biocompatibility and physicochemical characteristics. The aim of this work was to integrate the beneficial features of chitosan (CS) and OctaTMA-POSS nanoparticle to design nanocomposite for bone tissue regeneration. The nanocomposite scaffolds were fabricated by freeze-drying. The effects of POSS incorporation on morphology and structure of CS matrix were examined. Bioactivity and osteogenic effects of the POSS nanoparticles were investigated with cytocompatibility, cell proliferation, alkaline phosphatase activity, osteocalcin production and biomineralization assays. PUSS incorporation altered the surface morphology by increasing surface roughness. Nanocomposite scaffolds with 82-90% porosity exhibited an increase in compression modulus of scaffolds (78-107 kPa) compared to control CS group (56 kPa). Results indicated that CS-POSS scaffolds were found cytocompatible with 3T3, MG-63 and Saos-2 cell lines. POSS incorporation showed promising effects on osteoblast adhesion and proliferation as well as increasing ALP activity, octeocalcin secretion and biomineralization of cells. (C) 2019 Elsevier B.V. All rights reserved.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: 23Citation - Scopus: 27Novel Poss Reinforced Chitosan Composite Membranes for Guided Bone Tissue Regeneration(Springer Verlag, 2018) Tamburacı, Sedef; Tıhmınlıoğlu, FundaIn this study, novel composites membranes composed of chitosan matrix and polyhedral oligomeric silsesquioxanes (POSS) were fabricated by solvent casting method. The effect of POSS loading on the mechanical, morphological, chemical, thermal and surface properties, and cytocompatibility of composite membranes were investigated and observed by tensile test, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), protein adsorption assay, air/water contact angle analysis and WST-1 respectively. Swelling studies were also performed by water absorption capacity determination. Results showed that incorporation of Octa-TMA POSS® nanofiller to the chitosan matrix increased the surface roughness, protein adsorption and swelling capacity of membranes. The addition of POSS enhanced significantly the ultimate tensile strength and strain at break of the composite membranes up to 3 wt% POSS loaded samples. An increase of about 76% in tensile strength and of strain at break 1.28% was achieved for 3 wt% POSS loaded nanocomposite membranes compared with chitosan membranes. The presence of POSS filler into polymer matrix increased the plasma protein adsorption on the surface. Maximum protein capacity and swelling was obtained for 10 wt% loaded samples. High cell viability results were obtained with indirect extraction of chitosan/POSS composites. Besides, cell proliferation and ALP activity results showed that POSS incorporation significantly increased the ALP activity of Saos-2 cells cultured on chitosan membranes. This novel composite membranes with tunable properties could be considered as a potential candidate for guided bone regeneration applications