Browsing by Author "Durukan, Barkan Kagan"

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Design and Fabrication of Dual-Layered PCL/PEG Theranostic Platforms Using 3D Melt Electrowriting for Targeted Delivery and Post-Treatment Monitoring
(Springer, 2025) Ege, Zeynep Ruya; Enguven, Gozde; Ege, Hasan; Durukan, Barkan Kagan; Sasmazel, Hilal Turkoglu; Gunduz, Oguzhan
Advanced pancreatic tumors remain highly resistant to treatment due to their dense stromal environment and poor vascularization, which limit drug penetration and efficacy. Even after surgical resection, the high recurrence rate frequently leads to poor prognosis and mortality. To address these challenges, we developed solvent-free three-dimensional (3D) melt electrowritten (MEW) theranostic microfiber patches composed of poly(epsilon-caprolactone) (PCL) and polyethylene glycol (PEG). The patches were designed as dual-layered, 10-layer structures, with gemcitabine (GEM) loaded in the bottom five layers for localized chemotherapy to suppress tumor recurrence, and indocyanine green (ICG) incorporated in the top five layers to enable fluorescence-based post-surgical monitoring. Following fabrication, the patches were characterized both materially and in vitro, with GEM loaded at 100, 250, or 500 mu g/ml. PEG incorporation improved patch flexibility, facilitating the implantation process. In vitro release analysis demonstrated an initial burst followed by sustained, pH-responsive GEM release (similar to 70% at pH 4.0 and similar to 30% at pH 7.4 for 500 mu g/mL GEM at 168 h), while ICG release reached similar to 25% (pH 7.4) and similar to 10% (pH 4.0). GEM-loaded patches significantly reduced Capan-1 cell viability in a dose- and time-dependent manner, achieving >= 50% reduction at 72 h with 500 mu g/mL. Importantly, ICG incorporation did not impair GEM cytotoxicity; confocal imaging confirmed ICG internalization in viable cells and showed a decline in ICG-positive cells with increasing GEM dose, supporting the potential for concurrent therapy and monitoring. Thus, the theranostic patches enable localized, pH-responsive GEM delivery with integrated ICG-based fluorescence imaging, achieving significant cytotoxicity against pancreatic cancer cells while providing a platform for post-surgical surveillance. This solvent-free, layer-addressable approach represents a promising strategy for personalized, locally implantable theranostic systems in pancreatic cancer treatment.
Citation - WoS: 11
Citation - Scopus: 12
Modifying Niti Shape Memory Alloys To Reduce Nickel Ions Release Through Ethylenediamine Plasma Polymerization for Biomedical Applications
(Elsevier Science Sa, 2024) Durukan, Barkan Kagan; Sagdic, Kutay; Kockar, Benat; Inci, Fatih
Shape memory alloys (SMAs)-a type of smart materials- offer unique benefits for constructing unique medical implants, especially for heart stents, vertebral nails, and braces. One of the widespread SMAs is nitinol (NiTi) which exhibits extraordinary shape memory ability to recover its initial form. However, due to the result of nickel (Ni2+) ions release, long-term usage of NiTi alloys would pose allergic and carcinogenic risks in orthopedics and clinical applications. To tackle these hurdles, we here demonstrate a surface modification technique via plasma polymerization in order to minimize Ni2+ ions release. NiTi substrates were initially exploited by plasma polymerization of ethylenediamine (EDA) with varying power values (25-50-75-100 W) and time rates (5-10-15 min) in order to assess the most efficient parameters for minimal toxic metal release. The samples were then tested for 14 days in a biomimicked media. As a result, 75 W-10 min plasma polymerized sample reduced Ni2+ ions release by 57.18 % compared to the base specimen. These results offer a significant outcome in deploying NiTi alloys into the biomedical field more safely through surface modifications using the plasma polymerization technique.