Chemical Engineering / Kimya Mühendisliği

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  • Article
    Citation - WoS: 3
    Citation - Scopus: 4
    Microfluidic-Assisted Preparation of Nano and Microscale Chitosan Based 3d Composite Materials: Comparison With Conventional Methods
    (Wiley, 2022) Kimna, Ceren; Değer, Sibel; Tamburacı, Sedef; Tıhmınlıoğlu, Funda
    Although nanofillers contribute to improved physical characteristics and biological functionalities of polymer-based biomaterials, their dispersion in polymer matrices is still a challenging issue in terms of obtaining consistency for the inherent properties. To tackle this problem, homogenization techniques are applied to disperse the nanofillers in such polymers, however, these methods can cause undesired changes especially in the rheological properties and the physical structure of the biopolymer matrices. Recently, as a novel homogenization technique, microfluidization has been used to homogenize polymer nanocomposites to minimize these limitations. In this study, two different nanocomposite structures as chitosan/montmorillonite (CS/MMT) and chitosan/polyhedral oligomeric silsesquioxane nanocages (CS/POSS) were homogenized with microfluidization and investigated in terms of physical alterations. Furthermore, the effect of microfluidizer technique on material characteristics was compared with conventional homogenization techniques, i.e., ultrasonic bath and sonication in terms of solution, nano – (e.g., hydrodynamic size, drug encapsulation) and macroscopic material characteristics (e.g., porosity, mechanical properties, swelling and thermal degradation). It was found that the microfluidizer homogenization improves the physical characteristics in both nano and macroscale materials: Nanospheres obtained from CS/MMT composites showed enhanced stability, uniform size distribution (<100 nm, PDI: [removed]50%) whereas 3D porous CS/POSS scaffolds showed improved structural uniformity (i.e., homogeneous and interconnected microstructure) and enhanced thermal and mechanical properties. The obtained results indicate that the microfluidizer homogenization ensures a successful nanofiller dispersion in polymer matrices, thereby improving the biomaterial characteristics impressively compared to the sonication methods.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Synthesis and Characterization of Single-Walled Carbon Nanotube: Cyto-Genotoxicity in Allium Cepa Root Tips and Molecular Docking Studies
    (Wiley, 2022) İnce Yardımcı, Atike; İstifli, Erman Salih; Açıkbaş, Yaser; Liman, Recep; Yağmurcukardeş, Nesli; Yılmaz, Selahattin; Ciğerci, İbrahim Hakkı
    Herein, single-walled carbon nanotubes (SWCNTs) were synthesized by the thermal chemical vapor deposition (CVD) method, and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Raman spectroscopy, dynamic light scattering (DLS), and thermo-gravimetric analysis (TGA). The results indicated that obtained nanotubes were SWCNTs with high crystallinity and their average diameter was 10.15 ± 3 nm. Allium cepa ana–telophase and comet assays on the root meristem were employed to evaluate the cytotoxic and genotoxic effects of SWCNTs by examining mitotic phases, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage. A. cepa root tip cells were exposed to SWCNTs at concentrations of 12.5, 25, 50, and 100 μg/ml for 4 h. Distilled water and methyl methanesulfonate (MMS, 10 μg/ml) were used as the negative and positive control groups, respectively. It was observed that MIs decreased statistically significantly for all applied doses. Besides, CAs such as chromosome laggards, disturbed anaphase–telophase, stickiness and bridges and also DNA damage increased in the presence of SWCNTs in a concentration-dependent manner. In the molecular docking study, the SWCNT were found to be a strong DNA major groove binder showing an energetically very favorable binding free energy of −21.27 kcal/mol. Furthermore, the SWCNT interacted effectively with the nucleotides on both strands of DNA primarily via hydrophobic π and electrostatic interactions. As a result, cytotoxic and genotoxic effects of SWCNTs in A. cepa root meristematic cells which is a reliable system for assessment of nanoparticle toxicology were demonstrated in this study.