Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 5Citation - Scopus: 5Magnetically Controllable and Degradable Milliscale Swimmers as Intraocular Drug Implants(Wiley, 2025) Yildiz, E.; Bozuyuk, U.; Yildiz, E.; Wang, F.; Han, M.; Karacakol, A.C.; Sitti, M.Intraocular drug implants are increasingly used for retinal treatments, such as age-related macular degeneration and diabetic macular edema, due to the rapidly aging global population. Although these therapies show promise in arresting disease progression and improving vision, intraocular implant-based therapies can cause unexpected complications that require further surgery due to implant dislocation or uncontrolled drug release. These frequent complications of intraocular drug implants can be overcome using magnetically controllable degradable milliscale swimmers (MDMS) with a double-helix body morphology. A biodegradable hydrogel, polyethylene glycol diacrylate, is employed as the primary 3D printing material of MDMS, and it is magnetized by decorating it with biocompatible polydopamine-encapsulated iron-platinum nanoparticles. MDMS have comparable dimensions to commercial intraocular implants that achieve translational motions in both aqueous and vitreous bodies. They can be imaged in real-time using optical coherence tomography, ultrasound, and photoacoustic imaging. Thanks to their biodegradable hydrogel-based structure, they can be loaded with anti-inflammatory drug molecules and release the medications without disrupting retinal epithelial viability and barrier function, and decrease proinflammatory cytokine release significantly. These magnetically controllable swimmers, which degrade in a couple of months, can be used for less invasive and more precise intraocular drug delivery compared to commercial intraocular drug implants. © 2025 The Author(s). Advanced Science published by Wiley-VCH GmbH.Article Poly(Ethylene Glycol)-Keratin Hydrogels Prepared Via Thiol-Maleimide Reaction(Polymer Soc Korea, 2025) Yalcin, Damla; Top, AybenThe mechanical properties of hydrogels have a profound effect on cellular responses in tissue engineering applications. In this study, poly(ethylene glycol)-keratin (PEG-KRTN) hydrogels with tunable mechanical properties were prepared by varying molar mass of the maleimide functionalized PEG in the thiol-maleimide chemistry. Reduced keratins were reacted with PEG-maleimides having 2000 Da and 6000 Da molar masses. Viscoelastic and physiochemical properties and cytocompatibility of these hydrogels were tested. Storage modulus values were obtained as 2613 +/- 254 Pa and 1313 +/- 345 Pa for PEG2000-KRTN and PEG6000-KRTN hydrogels, respectively. Strain sweep data indicate that the linear viscoelastic region (LVER) of the PEG6000-KRTN hydrogel spans up to 40% strain value, whereas it is limited to 10% critical strain for the PEG2000-KRTN hydrogel. PEG6000-KRTN hydrogel presented higher swelling ratios and porosity. CCK-8 test showed that both hydrogels promoted the proliferation of L929 mouse fibroblast cells and, hence, can be applied in soft tissue engineering.Article Citation - WoS: 8Citation - Scopus: 9Development of Plant-Based Biopolymer Coatings for 3d Cell Culture: Boron-Silica Quince Seed Mucilage Nanocomposites(Royal Society of Chemistry, 2023) Yılmaz, Hilal Deniz; Cengiz, Uğur; Derkuş, Burak; Arslan, Yavuz EmreSpheroid formation with spontaneous aggregation has captured interest in most cell culture studies due to its easy set-up and more reliable results. However, the economic and technical costs of the advanced systems and commercial ultra-low adhesive platforms have pushed researchers into pursuing alternatives. Nowadays, polymeric coatings, including poly-hydroxyethyl methacrylate and agar/agarose, are the commonly used polymers for non-adhesive plate fabrication, yet the costs and working solvent or heat-dependent preparation procedures maintain the need for the development of novel biomaterials. Here, we propose a greener and more economical approach for producing non-adherent surfaces and spheroid formation. For this, a plant waste-based biopolymer from quince fruit (Cydonia oblonga Miller, from Rosaceae family) seeds and boron-silica precursors were introduced. The unique water-holding capacity of quince seed mucilage (Q) was enriched with silanol and borate groups to form bioactive and hydrophilic nanocomposite overlays for spheroid studies. Moreover, 3D gel plates from the nanocomposite material were fabricated and tested in vitro as a proof-of-concept. The surface properties of coatings and the biochemical and mechanical properties of the nanocomposite materials were evaluated in-depth with techniques, and extra hydrophilic coatings were obtained. Three different cell lines were cultured on these nanocomposite surfaces, and spheroid formation with increased cellular viability was recorded on day 3 with a >200 & mu;m spheroid size. Overall, Q-based nanocomposites are believed to be a fantastic alternative for non-adherent surface fabrication due to their low-cost, easy operation, and intrinsic hydration layer forming capacity with biocompatible nature in vitro.Article Citation - WoS: 5Citation - Scopus: 5Novel Biopolymer-Based Hydrogels Obtained Through Crosslinking of Keratose Proteins Using Tetrakis(hydroxymethyl) Phosphonium Chloride(Springer, 2022) Yalçın, Damla; Top, AybenMerino wool obtained from the Karacabey region of Turkey was solubilized using peracetic acid oxidation. The wool and extracted wool proteins (keratose) were characterized using SEM, XRD, TGA, and FTIR analyses. SDS-PAGE result of the keratose indicated diffusive bands were populated between ~ 40 and ~ 55 kDa, corresponding to low-sulfur content α-keratose proteins. Chemically crosslinked hydrogels were prepared using the keratose and tetrakis(hydroxymethyl) phosphonium chloride (THPC). Storage moduli of the hydrogels prepared at 1:1, 1:2, and 1:4 keratose to THPC reactive group ratios were measured as 63 ± 22, 291 ± 21, and 804 ± 53 Pa, respectively. Crosslinking degrees of the hydrogels also affected the secondary structures of the keratose films obtained from the drying of the hydrogels. The hydrogel with the highest crosslinking density (1:4 gel) exhibited the lowest swelling ratio, whereas the one with the lowest crosslinking density (1:1 gel) disintegrated in deionized water within less than 6 h. CCK-8 tests using L929 mouse fibroblast cells showed that all the hydrogels promoted cell proliferation. These results suggest THPC crosslinked hydrogels prepared at the millimolar THPC concentrations are biocompatible scaffolds, which can be utilized in drug delivery and tissue engineering applications. Graphical abstract: [Figure not available: see fulltext.]Article Citation - WoS: 5Citation - Scopus: 6Boosting Up Printability of Biomacromolecule Based Bio-Ink by Modulation of Hydrogen Bonding Pairs(Elsevier Ltd., 2020) Köksal, Büşra; Önbaş, Rabia; Başkurt, Mehmet; Şahin, Hasan; Arslan Yıldız, Ahu; Yıldız, Ümit HakanThis study describes low dose UV curable and bioprintable new bioink made of hydrogen bond donor-acceptor adaptor molecule 2-isocyanatoethyl methacrylate (NCO)modified gelatin (NCO-Gel). Our theoretical calculations demonstrate that insertion of 2-isocyanatoethyl methacrylate doubles the interaction energy (500 meV) between gelatin chains providing significant contribution in interchain condensation and self-organization as compared to methacrylic anhydride modified gelatin (GelMA). The NCO-Gel exhibits peak around 1720 cm?1 referring to bidentate hydrogen bonding between H-NCO and its counterpart O[dbnd]CN[sbnd]H. These strong interchain interactions drive chains to be packed and thereby facilitating UV crosslinking. The NCO-Gel is exhibiting a rapid, 10 s gelation process by the exposure of laser (3 W, 365 nm). The dynamic light scattering characterization also reveals that NCO-Gel has faster sol to gel transition as compared to GelMA depending on the UV curing time. The NCO-Gel was found to be more firm and mechanically strong that provides advantages in molding as well as bioprinting processes. Bioprinted NCO-Gel has shown sharp borders and stable 3D geometry as compared to GelMA ink under 10 s UV curing time. The cell viability tests confirm that NCO-Gel facilitates cell proliferation and supports cell viability. We foresee that NCO-Gel bioink formulation provides a promising opportunity when low dose UV curing and rapid printing are required. © 2020 Elsevier LtdArticle Citation - WoS: 24Citation - Scopus: 26Self-Assembly Behavior of the Keratose Proteins Extracted From Oxidized Ovis Aries Wool Fibers(Elsevier Ltd., 2019) Pakkaner, Efecan; Yalçın, Damla; Uysal, Berk; Top, AybenWater soluble keratose proteins were obtained from an Ovis Aries wool using peracetic acid oxidation. The wool samples and the extracted keratose proteins were characterized by using FTIR, XRD, SEM and TGA techniques. Fractions of alpha-keratose (MW = 43-53 kDa) along with protein species with molecular weights between 23 kDa and 33 kDa were identified in the SDS-PAGE analysis result of the extracted protein mixture. DLS and AFM experiments indicated that self-assembled globular nanoparticles with diameters between 15 nm and 100 nm formed at 5 mg/ml keratose concentration. On the other hand, upon incubation of 10 w % keratose solutions at 37 degrees C and 50 degrees C, interconnected keratose hydrogels with respective storage modulus (G') values of 0.17 +/- 0.03 kPa and 3.7 +/- 0.5 kPa were obtained. It was shown that the keratose hydrogel prepared at 37 degrees C supported L929 mouse fibroblast cell proliferation which suggested that these keratose hydrogels could be promising candidates in soft tissue engineering applications. (C) 2018 Elsevier B.V. All rights reserved.Article Citation - WoS: 17Citation - Scopus: 20Preparation and Characterization of Antibacterial Cobalt-Exchanged Natural Zeolite/Poly(vinyl Alcohol) Hydrogels(Springer Verlag, 2014) Narin, Güler; Bulut Albayrak, Çisem; Ülkü, SemraIn the present study, potential application of the local clinoptilolite-rich natural zeolite in formulation of antibacterial hydrogels was investigated. The zeolite powder exchanged with cobalt(II) ions was used in preparation of the zeolite/poly(vinyl alcohol) hydrogel films in different amounts. The films were physically crosslinked by the freezing-thawing method and characterized for their crystallinity, surface and cross sectional morphology, chemical composition, thermal behaviour, mechanical properties, swelling and dissolution behaviours, and antibacterial activities against a Gram-negative bacteria. The films with 0.48 wt% and higher cobalt-exchanged zeolite contents showed antibacterial activity. Addition of the zeolite powder in the formulations did not cause significant changes in the other properties of the films.Article Citation - WoS: 6Citation - Scopus: 6Fabrication of 3d Controlled in Vitro Microenvironments(Elsevier Ltd., 2014) Özdil, Berrin; Önal, Sevgi; Oruç, Tuğçe; Pesen Okvur, DevrimMicrofluidics-based lab-on-a-chips have many advantages, one of which is to provide physiologically relevant settings for cell biology experiments. Thus there is an ever increasing interest in their fabrication. Our goal is to construct three dimensional (3D) Controlled in vitro Microenvironments (CivMs) that mimic the in vivo microenvironments. Here, we present our optimized fabrication method that works for various lab-on-a-chip designs with a wide range of dimensions. The most crucial points are:While using one type of SU-8 photoresist (SU-2075), fine tuning of ramp, dwell time, spin speed, durations of soft bake, UV exposure and development allows fabrication of SU-8 masters with various heights from 40 to 600 μm.Molding PDMS (polydimethylsiloxane) at room temperature for at least two days instead of baking at higher temperatures prevents not only tears and bubbles in PDMS stamps but also cracks in the SU-8 master.3D nature of the CivMs is ensured by keeping the devices inverted during gel polymerization.