Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article A Potential Hemostatic Chitosan/Gelatin Cryogel Impregnated with Verbascum Thapsus Leaf Extract for Noncompressible Hemorrhage Management(IOP Publishing Ltd, 2025-11-01) Uzuner, Hacernur; Yuruk, Adile; Isoglu, Ismail AlperIn this study, we prepared a series of chitosan/gelatin (CS/GEL) cryogels containing Verbascum thapsus (V. thapsus) leaf extract and identified a lead formulation for noncompressible hemorrhage (NCH). Cryogels with average pore diameters ranging from 225 to 478 mu m were fabricated through cryogelation at various CS/GEL ratios. C15 was chosen as the base scaffold due to its homogeneous pore distribution, with a pore size coefficient of variation (CV) of approximately 0.22. Extract loading was 1%, 5%, 10%, and 20% w/v. Functional porosity was reported by the relative accessible void index (RAVI). In PBS, the values relative to neat C15 were 1.00, 0.27, 0.20, 0.13, and 0.09 for concentrations of 0%, 1%, 5%, 10%, and 20% w/v, respectively. In citrated blood, the series was 1.00, 0.29, 0.12, 0.14, and 0.09. After loading, equilibrium swelling decreased and the compressive modulus increased, consistent with partial pore filling in a fixed network. The cryogels maintained an interconnected macroporous network and showed swelling from 300% to 3600% in blood and PBS. Antibacterial activity reached 89% inhibition, and cell viability remained above 80%. Hemolysis was low and within acceptance limits. Clotting improved in whole blood as the blood clotting index decreased from 11.9 to 6.5, and the clotting time was approximately 6 min. The 5% w/v group provided the optimal balance of clotting, antibacterial effects, and biocompatibility. This study presents a novel hemostatic CS/GEL cryogel containing V. thapsus leaf extract that holds strong potential for future applications in NCH management.Article Engineering a Bilayered Scaffold as a Potential Cardiac Patch: From Scaffold Design to in Vitro Assessment(Springer Singapore Pte Ltd, 2025-11-24) Yuruk, Adile; Duzler, Ayhan; Isoglu, Sevil Dincer; Isoglu, Ismail AlperIn this study, we developed a novel bilayered scaffold consisting of a bottom layer composed of the Decellularized Bovine Pericardium (DP) coated with Polyaniline Nanoparticles (PANINPs) and a top layer made of an electrospun Poly(lactic-co-glycolic acid)/Gelatin (PLGA/Gel) membrane incorporated with Vascular Endothelial Growth Factor (VEGF) and hawthorn extract. Functionally, the DP supplies native Extracellular Matrix (ECM) components and mechanical support, while PANINPs provide conductivity. The electrospun PLGA/Gel layer mimics fibrous ECM. It incorporates bioactives, with VEGF promoting pro-angiogenic stimulation and hawthorn extract enhancing anticoagulant activity, as well as increasing surface hydrophilicity. The tissue adhesive ensures the interfacial integrity between the two layers. Decellularization efficiency was confirmed histologically using 4 ',6-diamidino-2-phenylindole (DAPI) and Hematoxylin-Eosin (H&E) staining. The DP exhibited a DNA content of 115.9 +/- 47.8 ng/mg DNA, compared to 982.88 +/- 395.42 ng/mg in Native Pericardium (NP). The PANINPs had an average particle size of 104.94 +/- 13.7 nm. The conductivity of PANINPs-coated decellularized pericardium was measured to be 9.093 +/- 8.6 x 10- 4 S/cm using the four-point probe method. PLGA/Gel membranes containing hawthorn extract (1%, 5%, 10%, and 15% w/v) and VEGF (0.1 mu g/mL, 0.5 mu g/mL, and 1 mu g/mL) were fabricated by electrospinning, resulting in fiber diameters between 850 and 1200 nm and pore sizes between 14 and 20 mu m. The anticoagulant efficiency of the membranes containing hawthorn extract reached 430 s in the Activated Partial Thromboplastin Time Assay (aPTT). Mechanical testing revealed a tensile strength of 22.70 +/- 6.33 MPa, an elongation of 53.58 +/- 10.63%, and Young's modulus of 0.67 +/- 0.10 MPa. The scaffold also exhibited over 91% cell viability and excellent cardiomyocyte adhesion. The hemolysis ratio was determined to be 0.421 +/- 0.191%, which confirms its blood compatibility. Our results indicate that the proposed bilayered scaffold can be a promising candidate for cardiac patch applications.Article Tuning Mechanical Performance of PCL Scaffolds: Influence of 3D Bioprinting Parameters, Polymer Concentration, and Solvent Selection(IOP Publishing Ltd, 2025-09-01) Ceylan, Saniye Aylin; Baltacioglu, Mehmet Furkan; Bal, Burak; Bayram, Ferdi Caner; Isoglu, Ismail AlperThe mechanical performance of three-dimensional (3D) bioprinted scaffolds is susceptible to printing parameters and material formulation. In this study, poly (epsilon-caprolactone) (PCL) scaffolds were fabricated using four different polymer concentrations (10%, 25%, 50%, and 75% w/v) to investigate how these variations, along with process parameters, influence mechanical behavior. Maintaining the structural integrity of bioprinted constructs requires careful optimization of polymer concentration and precise control over parameters such as printing speed, pressure, and infill density. Tensile tests were conducted to evaluate the effects of these variables. Among the tested conditions, a 50% (w/v) concentration allowed for a broader operational window, enabling fabrication across a range of printing speeds and pressures. At a printing speed of 5 mm s-1, PCL-DCM exhibited a Young's modulus of 39.0 MPa, while PCL-CF samples printed at 10 mm s-1 achieved the highest modulus of 32.0 MPa. Notably, when the printing speed was kept constant, applying higher pressures led to an increase in Young's modulus, suggesting that pressure plays a key role in enhancing scaffold stiffness. When comparing the 50% and 75% (w/v) polymer concentrations, the 50% (w/v) formulation stood out by offering both higher elongation and greater stiffness, which makes it particularly suitable for load-bearing applications. These findings provide a quantitative framework for optimizing extrusion-based bioprinting of PCL scaffolds, with implications for customized biomedical implants and regenerative medicine.Article Citation - WoS: 13Citation - Scopus: 13Sulfobetaine-Based Homo- and Copolymers by Raft: Cross-Linked Micelles and Aqueous Solution Properties(Amer Chemical Soc, 2022-08-04) Gurdap, Seda; Bayram, Nazende Nur; Isoglu, Ismail Alper; Isoglu, Sevil Dincer; Dinçer İşoǧlu, SevilIn this study, we describe the synthesis and aqueous solution behavior of temperature-sensitive N-(3-sulfopropyl)-N-methacroyloxyethyl-N,N-dimethylammonium betaine (SBMA) homopolymers and core cross-linked micelles (CCMs) with an SBMA shell. Reversible addition- fragmentation chain transfer polymerization has been utilized to synthesize sulfobetaine homopolymers, followed by CCM formation during copoly-merization in the presence of an acid-degradable cross-linker. First, SBMA homopolymers of varying chain lengths were synthesized, and it has been demonstrated that an increase in the chain length and concentration of the homopolymer resulted in an increase in the upper critical solution temperature (UCST). Besides, micelles showed concentration-dependent dual temperature-sensitive behavior with UCST and LCST transitions. Also, homopolymers and CCMs were characterized by FTIR, H-1-NMR, GPC, and TEM. Micelle formation and temperature sensitivity were also investigated by DLS. As a result, stabilized micelles were successfully prepared with the motivation of preventing premature drug release and achieving a pH-and temperature-controlled system. Due to their dual-responsive characteristics, the CCMs show promising potential to be used as smart drug carriers for controlled delivery.Article Citation - WoS: 8Citation - Scopus: 11Stem Cells Combined 3D Electrospun Nanofibrous and Macrochannelled Matrices: A Preliminary Approach in Repair of Rat Cranial Bones(Taylor & Francis Ltd, 2019-04-03) Isoglu, Ismail Alper; Bolgen, Nimet; Korkusuz, Petek; Vargel, Ibrahim; Celik, Hakan Hamdi; Kilic, Emine; Piskin, ErhanRepair of cranial bone defects is an important problem in the clinical area. The use of scaffolds combined with stem cells has become a focus in the reconstruction of critical-sized bone defects. Electrospinning became a very attracting method in the preparation of tissue engineering scaffolds in the last decade, due to the unique nanofibrous structure of the electrospun matrices. However, they have a limitation for three dimensional (3D) applications, due to their two-dimensional structure and pore size which is smaller than a cellular diameter which cannot allow cell migration within the structure. In this study, electrospun poly(epsilon-caprolactone) (PCL) membranes were spirally wounded to prepare 3D matrices composed of nanofibers and macrochannels. Mesenchymal stromal/stem cells were injected inside the scaffolds after the constructs were implanted in the cranial bone defects in rats. New bone formation, vascularisation and intramembranous ossification of the critical size calvarial defect were accelerated by using mesenchymal stem cells combined 3D spiral-wounded electrospun matrices.Article Citation - WoS: 8Citation - Scopus: 7Raft-Synthesized Poegma-B Block Copolymers: Preparation of Nanosized Micelles for Anticancer Drug Release(Springer, 2021-11-14) Bayram, Nazende Nur; Topuzogullari, Murat; Isoglu, Ismail Alper; Isoglu, Sevil Dincer; Dinçer İşoğlu, SevilTo achieve high stability and biocompatibility in physiological environment, oligoethyleneglycol methacrylate (OEGMA) and 4-vinylpyridine (4VP)-based amphiphilic block copolymers were prepared as micellar carriers to deliver doxorubicin into tumor cells. First, macroinitiator of OEGMA was synthesized by RAFT polymerization at [M](0)/[CTA](0)/[I](0) ratio of 100/1/0.2 in dimethylformamide (DMF) at 70 degrees C, in the presence of 4,4'-azobis(4-cyanovaleric acid) (ACVA) as initiator and 4-cyano-4-(thiobenzoylthio)pentanoic acid (CTA) as chain transfer agent, respectively. It was followed by copolymerization with 4-VP at similar conditions. The formation of RAFT-mediated polymers was approved by FTIR, H-1-NMR and GPC. For the preparation of drug-loaded micelles, a dialysis method was applied and hydrophobic doxorubicin, as a model drug, was entrapped into the micelles. Size distributions and morphologies of drug-loaded micelles were investigated by light scattering and scanning electron microscopy, respectively. Critical micelle concentration was estimated as 0.0019 mg/mL by measuring light scattering intensity in different polymer concentrations. Also, drug loading and entrapment efficiencies were calculated as 4.41% and 17.65% by measuring the DOX amount in the micelles, spectrophotometrically. At last, the drug-loaded micelles were applied to SKBR-3 breast cancer cell lines and revealed up to %40 cell inhibition at 48 and 72 h. As a result, these nanosized and biocompatible micelles can be used for the delivery of hydrophobic drugs, and they can also be modified for further targeting and imaging applications toward specific cancer cells. [GRAPHICS] .Article Citation - WoS: 8Citation - Scopus: 8RAFT-Mediated Synthesis of Poly( N-(2-Hydroxypropyl)Methacrylamide-b-4-vinylpyridine)by Conventional and Microwave Heating(Springer, 2013-06-14) Ozdemir, Zeynep; Topuzogullari, Murat; Isoglu, Ismail Alper; Dincer, SevilWe report the synthesis of N-(2-hydroxypropyl)methacrylamide (HPMA) macroCTA and HPMA-b-4-Vinylpyridine block copolymers via reversible addition-fragmentation chain transfer (RAFT) reaction. Polymerization was carried out in dimethylformamide (DMF) at 70 A degrees C using 4-Cyano-4(thiobenzoylthio) pentanoic acid as chain transfer agent and AIBN as an initiator. Control over molecular weight and composition was achieved by altering the CTA, monomer and initiator feed ratio. The controlled living character of the polymerization was verified with pseudo-first-order kinetic plots, a linear increase of the molecular weight with conversion, and low polydispersities (PDIs a parts per thousand currency sign 1.2). Effect of microwave heating on the homo- and copolymer formation was investigated and the rates were significantly higher than those observed under conventional heating conditions. These polymerization reactions were in controlled fashion resulting in polymers with low PDIs, too. These polymers have a great potential to be used in developing delivery vehicles and conjugates for further drug or gene delivery applications.Article Citation - WoS: 14Citation - Scopus: 15Preparation of Antibacterial Electrospun Poly(D, L-Lactide-co-Glycolide)/Gelatin Blend Membranes Containing Hypericum Capitatum Var. Capitatum(Taylor & Francis As, 2020-05-18) Aksit, Nazende Nur; Gurdap, Seda; Isoglu, Sevil Dincer; Isoglu, Ismail AlperIn this study, we fabricated poly(D, L-lactide-co-glycolide)/gelatin (PLGA/gelatin) membranes containing different amounts of Hypericum capitatum var. capitatum (HCC) extract (1, 5, 7.5, 10 wt%) by electrospinning technique. We investigated chemical, morphological, physical, and mechanical properties as well as in vitro degradation behavior of the electrospun membranes. We also evaluated the antibacterial activity of the electrospun membranes against Escherichia coli and Staphylococcus aureus. Viability, adhesion, and attachment of human fibroblast cells on the electrospun membranes on pre-set days were evaluated by the colorimetric CellTiter 96(R) AQueous One Solution Cell Proliferation Assay (MTS assay), scanning electron microscopy (SEM), and 4',6-Diamidino-2-Phenylindole (DAPI) staining.Article Citation - WoS: 5Citation - Scopus: 5Preparation and Characterization of Viburnum Opulus Containing Electrospun Membranes as Antibacterial Wound Dressing(Korean Fiber Soc, 2023-09-22) Yuruk, Adile; Isoglu, Sevil Dincer; Isoglu, Ismail AlperHerein, we fabricated polycaprolactone/gelatin electrospun membranes possessing different amounts of Viburnum Opulus extract (0, 25, 35, 50%, w/v) as an antibacterial wound dressing. We investigated chemical, morphological, physical, and mechanical properties as well as in vitro degradation behavior of the electrospun membranes. The antibacterial activities of membranes were evaluated against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli). The membranes containing Viburnum Opulus exhibited excellent antibacterial activity with the formation of inhibition zones of 25 mm to 36 mm against Escherichia coli and 14 mm to 25 mm against Staphylococcus aureus. The fiber diameters rose from 591 to 1222 nm after adding Viburnum Opulus extract. The extract-containing membranes displayed superior swelling, cell viability, and proliferation properties to neat membranes. Our results showed that the polycaprolactone/gelatin electrospun membranes containing Viburnum Opulus could be a suitable material for wound dressing applications.Article Citation - WoS: 3Citation - Scopus: 3Pericardial Fluid and Vascular Tissue Engineering: A Preliminary Study(Ios Press, 2021-03-23) Sonmezer, Dilek; Latifoglu, Fatma; Toprak, Guler; Duzler, Ayhan; Isoglu, Ismail AlperBACKGROUND: The heart is surrounded by a membrane called pericardium or pericardial cavity. OBJECTIVE: In this study, we investigated the pericardial fluid (PF) for coating polycaprolactone (PCL) scaffolds. PFS, which is a PF component, was used for the coating material. In addition to using PFS for surface coating, MED and fetal bovine serum (FBS) were also used for comparison. METHODS: Pericardial fluid cells (PFSc) isolated from PF were cultured on coated PCL scaffolds for 1, 3, and 5 days. Cell viability was determined using 3-(4, 5-di-methylthiazol- 2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. RESULTS: The MTT assay results showed that the viability of cells on PCL scaffold coated with PFS increased over time (P < 0.005), and cell viability was significantly different between PCL scaffolds coated with PFS and non-coated PCL scaffolds. However, cell viability was significantly higher in the PCL scaffolds coated with PFS than non-coated and coated with FBS, MED, and PCL scaffolds. Scanning electron microscopy (SEM) microscopy images and MTT assay indicated that PFSc are attached, proliferated, and spread on PCL scaffolds, especially on PCL scaffolds coated with PFS. CONCLUSIONS: These results suggest that PFS is a biocompatible material for surface modification of PCL scaffolds, which can be used as a suitable material for tissue engineering applications.