PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 7Citation - Scopus: 6Thickness Gradient in Polymer Coating by Reactive Layer-By Assembly on Solid Substrate(Amer Chemical Soc, 2023) Özenler, Sezer; Yıldız, Ümit Hakan; Özenler, Sezer; Dağlar, Özgün; Durmaz, Hakan; Yıldız, Ümit Hakan; 04.01. Department of Chemistry; 01. Izmir Institute of Technology; 04. Faculty of ScienceThe study describes a simple yet robust methodology for forming gradients in polymer coatings with nanometer-thickness precision. The thickness gradients of 0-20 nm in the coating are obtained by a reactive layer-by-layer assembly of polyester and polyethylenimine on gold substrates. Three parameters are important in forming thickness gradients: (i) the incubation time, (ii) the incubation concentration of the polymer solutions, and (iii) the tilt angle of the gold substrate during the dipping process. After examining these parameters, the characterization of the anisotropic surface obtained under the best conditions is presented in the manuscript. The thickness profile and nanomechanical characterization of the polymer gradients are characterized by atomic force microscopy. The roughness analysis has demonstrated that the coating exhibited decreasing roughness with increasing thickness. On the other hand, Young's moduli of the thin and thick coatings are 0.50 and 1.4 MPa, respectively, which assured an increase in mechanical stability with increasing coating thickness. Angle-dependent infrared spectroscopy reveals that the C-O-C ester groups of the polyesters exhibit a perpendicular orientation to the surface, while the C=C groups are parallel to the surface. The surface properties of the polymer gradients are explored by fluorescence microscopy, proving that the dye's fluorescence intensity increases as the coating thickness increases. The significant benefit of the suggested methodology is that it promises thickness control of gradients in the coating as a consequence of the fast reaction kinetics between layers and the reaction time.Article Citation - WoS: 26Citation - Scopus: 27Dopamine-Conjugated Bovine Serum Albumin Nanoparticles Containing Ph-Responsive Catechol-V(iii) Coordination for in Vitro and in Vivo Drug Delivery(Amer Chemical Soc, 2023) Argıtekin, Eda; Akdoğan, Yaşar; Çakan-Akdoğan, Gülçin; Akdoğan, Yaşar; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyV(III) instead of commonly used Fe(III) provided a richtris-catechol-metalcoordination at pH 7.4, which is important for slow drug release atphysiological pH. Bovine serum albumin (BSA) functionalized with catechol-containingdopamine (D) and cross-linked using tris-catechol-V(III) coordinationyielded pH-responsive compact D-BSA NPs (253 nm). However, conversionto bis- and/or mono-catechol-V(III) complexes in an acidic mediumresulted in degradation of NPs and rapid release of doxorubicin (DOX).It was shown that D-BSA NPs entered cancerous MCF-7 cells (66%) moreefficiently than non-cancerous HEK293T (33%) in 3 h. Also, DOX-loadedNPs reduced cell viability of MCF-7 by 75% and induced apoptosis ina majority of cells after 24 h. Biodegradability and lack of hemolyticactivity were shown in vitro, whereas a lack of toxicity was shownin histological sections of zebrafish. Furthermore, 30% of circulatingtumor cells in vasculature in 24 h were killed by DOX-loaded NPs shownwith the zebrafish CTC xenograft model.Article Citation - Scopus: 11Fabrication of Helix Aspersa Extract Loaded Gradient Scaffold With an Integrated Architecture for Osteochondral Tissue Regeneration: Morphology, Structure, and in Vitro Bioactivity [1](Amer Chemical Soc, 2023) Tamburaci, Sedef; Perpelek, Merve; Aydemir, Selma; Baykara, Basak; Havitcioğlu, Hasan; Tihminlioğlu, Funda; 01. Izmir Institute of TechnologyRegeneration of osteochondral tissue with its layered complex structure and limited self-repair capacity has come into prominence as an application area for biomaterial design. Thus, literature studies have aimed to design multilayered scaffolds using natural polymers to mimic its unique structure. In this study, fabricated scaffolds are composed of transition layers both chemically and morphologically to mimic the gradient structure of osteochondral tissue. The aim of this study is to produce gradient chitosan (CHI) scaffolds with bioactive snail (Helix aspersa) mucus (M) and slime (S) extract and investigate the structures regarding their physicochemical, mechanical, and morphological characteristics as well as in vitro cytocompatibility and bioactivity. Gradient scaffolds (CHI-M and CHI-S) were fabricated via a layer-by-layer freezing and lyophilization technique. Highly porous and continuous 3D structures were obtained and observed with SEM analysis. In addition, scaffolds were physically characterized with water uptake test, micro-CT, mechanical analysis (compression tests), and XRD analysis. In vitro bioactivity of scaffolds was investigated by co-culturing Saos-2 and SW1353 cells on each compartment of gradient scaffolds. Osteogenic activity of Saos-2 cells on extract loaded gradient scaffolds was investigated in terms of ALP secretion, osteocalcin (OC) production, and biomineralization. Chondrogenic bioactivity of SW1353 cells was investigated regarding COMP and GAG production and observed with Alcian Blue staining. Both mucus and slime incorporation in the chitosan matrix increased the osteogenic differentiation of Saos-2 and SW1353 cells in comparison to the pristine matrix. In addition, histological and immunohistological staining was performed to investigate ECM formation on gradient scaffolds. Both characterization and in vitro bioactivity results indicated that CHI-M and CHI-S scaffolds show potential for osteochondral tissue regeneration, mimicking the structure as well as enhancing physical characteristics and bioactivity.