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Öğe A Facile Strategy for Preparing Flexible and Porous Hydrogel-Based Scaffolds from Silk Sericin/Wool Keratin by In Situ Bubble-Forming for Muscle Tissue Engineering Applications(Wiley-V C H Verlag Gmbh, 2024) Demiray, Elif Beyza; Sezgin Arslan, Tugba; Derkus, Burak; Arslan, Yavuz EmreIn the present study, it is aimed to fabricate a novel silk sericin (SS)/wool keratin (WK) hydrogel-based scaffolds using an in situ bubble-forming strategy containing an N-(3-dimethylaminopropyl)-N '-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) coupling reaction. During the rapid gelation process, CO2 bubbles are released by activating the carboxyl groups in sericin with EDC and NHS, entrapped within the gel, creating a porous cross-linked structure. With this approach, five different hydrogels (S2K1, S4K2, S2K4, S6K3, and S3K6) are constructed to investigate the impact of varying sericin and keratin ratios. Analyses reveal that more sericin in the proteinaceous mixture reinforced the hydrogel network. Additionally, the hydrogels' pore size distribution, swelling ratio, wettability, and in vitro biodegradation rate, which are crucial for the applications of biomaterials, are evaluated. Moreover, biocompatibility and proangiogenic properties are analyzed using an in-ovo chorioallantoic membrane assay. The findings suggest that the S4K2 hydrogel exhibited the most promising characteristics, featuring an adequately flexible and highly porous structure. The results obtained by in vitro assessments demonstrate the potential of S4K2 hydrogel in muscle tissue engineering. However, further work is necessary to improve hydrogels with an aligned structure to meet the features that can fully replace muscle tissue for volumetric muscle loss regeneration. A novel hydrogel-based bioengineered scaffold with a porous and flexible ultrastructure is fabricated via in situ crosslinking of sericin and keratin. In chorioallantoic membrane analysis, the bioengineered scaffold not only shows angiogenic potential but also promotes the biological behavior of C2C12 muscle cells. These results highlight the potential of the sericin/keratin scaffold for future applications in repairing volumetric muscle tissue loss. imageÖğe Decellularized spinal cord meninges extracellular matrix hydrogel that supports neurogenic differentiation and vascular structure formation(John Wiley and Sons Ltd, 2021) Özüdoğru, Eren; Işık, Melis; Eylem, Cemil Can; Nemutlu, Emirhan; Arslan, Yavuz Emre; Derkus, BurakDecellularization of extracellular matrices offers an alternative source of regenerative biomaterials that preserve biochemical structure and matrix components of native tissues. In this study, decellularized bovine spinal cord meninges (dSCM)-derived extracellular matrix hydrogel (MeninGEL) is fabricated by employing a protocol that involves physical, chemical, and enzymatic processing of spinal meninges tissue and preserves the biochemical structure of meninges. The success of decellularization is characterized by measuring the contents of residual DNA, glycosaminoglycans, and hydroxyproline, while a proteomics analysis is applied to reveal the composition of MeninGEL. Frequency and temperature sweep rheometry show that dSCM forms self-supporting hydrogel at physiological temperature. The MeninGEL possesses excellent cytocompatibility. Moreover, it is evidenced with immuno/histochemistry and gene expression studies that the hydrogel induces growth-factor free differentiation of human mesenchymal stem cells into neural-lineage cells. Furthermore, MeninGEL instructs human umbilical vein endothelial cells to form vascular branching. With its innate bioactivity and low batch-to-batch variation property, the MeninGEL has the potential to be an off-the-shelf product in nerve tissue regeneration and restoration.Öğe Detergent-free decellularization of bovine costal cartilage for chondrogenic differentiation of human adipose mesenchymal stem cells in vitro(Royal Soc Chemistry, 2016) Erten, Evren; Arslan, Tugba Sezgin; Derkus, Burak; Arslan, Yavuz EmreIn this study, we report a novel, detergent-free decellularization protocol for the preparation of intact cartilage ECM-based scaffolds (CEbS) during an effective decalcification process. On treatment with 10 mM Na(2)EDTA, the amount of calcium lost was around 55% +/- 5% (percent +/- S.D.%) (n = 3) and nearly 84% of the nuclear material was removed; however, the most effective removal was observed on treatment with 10 mM Na2EDTA combined with 0.5% Triton X-100 for 48 hours. Notably, our proposed method decreased the GAG content by only 5% compared to untreated CEbS (380.37 +/- 16.02 mu g mg(-1) dry weight). There was no significant difference in hydroxyproline content between the untreated (13.04 +/- 1.51 mg mg(-1) dry weight) sample and our proposed method (12.95 +/- 1.55 mg mg(-1) dry weight). The scaffold morphology and cell attachment were evaluated using SEM micrographs, and the cells that were inoculated with detergent-free decellularized CEbS for 14, 21 and 28 days covered the scaffold area, including the porous cavities. Microscopic observations showed that the cell density increased day by day and there was no cytotoxic evidence for the scaffolds, which is a desirable environment for cells. The histochemical and immunohistochemical assessments are supported by glycosaminoglycan and hydroxyproline assays. The proposed detergent-free decellularization technique could be a promising method for cartilage tissue regeneration.Öğe Development and characterization of skin substitutes from electrospun polycaprolactone/silk fibroin(SAGE Publications Ltd, 2024) Yıldız, Gülşah; Arslan, Yavuz Emre; Derkus, Burak; Sezgin, Billur; Menceloglu, Yusuf Ziya; Bayar, Gürkan RaşitTissue-engineered skin substitutes have great potential to treat chronic wounds and high-degree burns. Existing solutions, such as Integra Dermal Template, are extensively used for skin defects. However, these templates are still lacking in terms of recreating the functionality of the native tissue and providing scarless healing. In this study, polycaprolactone/silk fibroin (PCL/SF)-based nanofibers with varying blends were fabricated and characterized to develop a novel skin substitute. Morphological analysis showed that the nanofiber distribution of each sample was homogenous without showing any beads. In terms of mechanical properties, all the samples other than SF showed sufficient mechanical strength. It was observed that adding a specific amount of SF into the PCL nanofiber improves the tensile strength of the samples due to the introduction of intermolecular interactions from the functional groups of SF. In addition, incorporating SF into PCL improved Young’s modulus of the PCL nanofibers since SF provides stiffness and structural integrity to the overall structure. Water contact angle analysis was performed as the hydrophilicity of a biomaterial is a significant factor in cell functionality. Each sample had a contact angle between 33° and 48°, indicating the adequate hydrophilicity of nanofibers for advanced cell proliferation other than PCL. Cell proliferation and viability studies were conducted with the seeding of primary human keratinocytes on the samples. It was examined that scaffolds containing blends of PCL and SF resulted in higher cell proliferation and viability after 7 days compared to pure PCL and SF nanofibers.Öğe Development of a novel aptasensor using jellyfish collagen as matrix and thrombin detection in blood samples obtained from patients with various neurodisease(Elsevier Science Sa, 2016) Derkus, Burak; Arslan, Yavuz Emre; Bayrac, Abdullah Tahir; Kantarcioglu, Ilkim; Emregul, Kaan C.; Emregul, EmelIn the present study, we describe the isolation and detailed characterization of pepsin-soluble atelocollagen from Rhizostoma pulmo species jellyfish and application towards thrombin apta-sensing. Various analysis methods including infra-red spectroscopy, SDS-PAGE electrophoresis, and amino acid analysis have been applied for the characterization of jellyfish collagen and compared with both rat tail collagen and BSA. When comparing the two collagen types derived from jellyfish and rat tail, jellyfish collagen was observed to contain a relatively high amount of glutamic acid (61 residues/1000 residues) and alanine (63 residues/1000 residues) but low amounts of proline (113 residues/1000 residues). On the other hand, pepsin-soluble jellyfish collagen contained a small quantity of tyrosine indicating the purity of atelo-collagen. Electrochemical impedance spectroscopy is the main analyzing technique of the developed apta-sensor. The proposed apta-sensor has a detection limit of 6.25 nM thrombin. Clinical application were performed with analysis of the thrombin levels in blood and CSF samples obtained from patients with Multiple Sclerosis, Myastenia Gravis, Epilepsy, Parkinson, Polyneuropathy and healthy donors using both the apta-sensor and commercial ELISA kit. The results revealed the proposed system to be a promising candidate for clinical analysis of thrombin. (C) 2016 Elsevier B.V. All rights reserved.Öğe Enhancement of aptamer immobilization using egg shell-derived nano-sized spherical hydroxyapatite for thrombin detection in neuroclinic(Elsevier Science Bv, 2016) Derkus, Burak; Arslan, Yavuz Emre; Emregul, Kaan C.; Emregul, EmelIn the present study, we describe the sonochemical isolation of nano-sized spherical hydroxyapatite (nHA) from egg shell and application towards thrombin aptasensing. In addition to the sonochemical method, two conventional methods present in literature were carried out to perform a comparative study. Various analysis methods including Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Energy Dispersive Analysis of X-Rays (EDAX), and Thermal Gravimetric Analysis (TGA) have been applied for the characterization of nHA and its nanocomposite with marine-derived collagen isolated from Rhizostoma pulmo jellyfish. TEM micrographs revealed the sonochemically synthesized nHA nanoparticles to have a unique porous spherical shape with a diameter of approximately 60-80 nm when compared to hydroxyapatite nanoparticles synthesized using the other two methods which had a typical needle shaped morphology. EDAX, XRD and FTIR results demonstrated that the obtained patterns belonged to hydroxyapatite. Electrochemical impedance spectroscopy (EIS) is the main analyzing technique of the developed thrombin aptasensor. The proposed aptasensor has a detection limit of 0.25 nM thrombin. For clinical application of the developed aptasensor, thrombin levels in blood and cerebrospinal fluid (CSF) samples obtained from patients with Multiple Sclerosis, Myastenia Gravis, Epilepsy, Parkinson, polyneuropathy and healthy donors were analyzed using both the aptasensor and commercial ELISA kit. The results showed that the proposed system is a promising candidate for clinical analysis of thrombin. (C) 2016 Elsevier B.V. All rights reserved.Öğe Fabrication of human hair keratin/jellyfish collagen/eggshell-derived hydroxyapatite osteoinductive biocomposite scaffolds for bone tissue engineering: From waste to regenerative medicine products(Elsevier, 2017) Arslan, Yavuz Emre; Arslan, Tugba Sezgin; Derkus, Burak; Emregul, Emel; Emregul, Kaan C.In the present study, we aimed at fabricating an osteoinductive biocomposite scaffold using keratin obtained from human hair, jellyfish collagen and eggshell-derived nano-sized spherical hydroxyapatite (nHA) for bone tissue engineering applications. Keratin, collagen and nHA were characterized with the modified Lowry method, free-sulfhydryl groups and hydroxyproline content analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and thermal gravimetric analysis (TGA) which confirmed the success of the extraction and/or isolation processes. Human adipose mesenchymal stem cells (hAMSCs) were isolated and the cell surface markers were characterized via flow cytometry analysis in addition to multi lineage differentiation capacity. The undifferentiated hAMSCs were highly positive for CD29, CD44, CD73, CD90 and CD105, but were not seen to express hematopoietic cell surface markers such as CD14, CD34 and CD45. The cells were successfully directed towards osteogenic, chondrogenic and adipogenic lineages in vitro. The microarchitecture of the scaffolds and cell attachment were evaluated using scanning electron microscopy (SEM). The cell viability on the scaffolds was assessed by the MTT assay which revealed no evidence of cytotoxicity. The osteogenic differentiation of hAMSCs on the scaffolds was determined histologically using alizarin red S, osteopontin and osteonectin stainings. Early osteogenic differentiation markers of hAMSCs were significantly expressed on the collagen-keratin-nHA scaffolds. In conclusion, it is believed that collagen-keratin-nHA osteoinductive biocomposite scaffolds have the potential of being used in bone tissue engineering. (C) 2017 Elsevier B.V. All rights reserved.Öğe Sophisticated Biocomposite Scaffolds from Renewable Biomaterials for Bone Tissue Engineering(Springer International Publishing Ag, 2019) Arslan, Yavuz Emre; Ozudogru, Eren; Arslan, Tugba Sezgin; Derkus, Burak; Emregul, Emel; Emregul, Kaan C.[Anstract Not Available]Öğe Supercritical CO2-Mediated Decellularization of Bovine Spinal Cord Meninges: A Comparative Study for Decellularization Performance(Amer Chemical Soc, 2024) Ozudogru, Eren; Kurt, Tugce; Derkus, Burak; Cengiz, Ugur; Arslan, Yavuz EmreThe extracellular matrix (ECM) of spinal meninge tissue closely resembles the wealthy ECM content of the brain and spinal cord. The ECM is typically acquired through the process of decellularizing tissues. Nevertheless, the decellularization process of the brain and spinal cord is challenging due to their high-fat content, in contrast to the spinal meninges. Hence, bovine spinal cord meninges offer a promising source to produce ECM-based scaffolds, thanks to their abundance, accessibility, and ease of decellularization for neural tissue engineering. However, most decellularization techniques involve disruptive chemicals and repetitive rinsing processes, which could lead to drastic modifications in the tissue ultrastructure and a loss of mechanical stability. Over the past decade, supercritical fluid technology has experienced considerable advancements in fabricating biomaterials with its applications spreading out to tissue engineering to tackle the complications mentioned above. Supercritical carbon-dioxide (scCO2)-based decellularization procedures especially offer a significant advantage over classical decellularization techniques, enabling the preservation of extracellular matrix components and structures. In this study, we decellularized the bovine spinal cord meninges by seven different methods. To identify the most effective approach, the decellularized matrices were characterized by dsDNA, collagen, and glycosaminoglycan contents and histological analyses. Moreover, the mechanical properties of the hydrogels produced from the decellularized matrices were evaluated. The novel scCO2-based treatment was completed in a shorter time than the conventional method (3 versus 7 days) while maintaining the structural and mechanical integrity of the tissue. Additionally, all hydrogels derived from scCO2-decellularized matrices demonstrated high cell viability and biocompatibility in a cell culture. The current study suggests a rapid, effective, and detergent-free scCO2-assisting decellularization protocol for clinical tissue engineering applications.Öğe Synthesis of Silica-Based Boron-Incorporated Collagen/Human Hair Keratin Hybrid Cryogels with the Potential Bone Formation Capability(Amer Chemical Soc, 2021) Cal, Fatma; Sezgin Arslan, Tugba; Derkus, Burak; Kiran, Fadime; Cengiz, Ugur; Arslan, Yavuz EmreTissue engineering and regenerative medicine have evolved into a different concept, the so-called clinical tissue engineering. Within this context, the synthesis of next-generation inorganic-organic hybrid constructs without the use of chemical crosslinkers emerges with a great potential for treating bone defects. Here, we propose a sophisticated approach for synthesizing cost-effective boron (B)- and silicon (Si)-incorporated collagen/hair keratin (B-Si-Col-HK) cryogels with the help of sol-gel reactions. In this approach, collagen and hair keratin were engaged with a B-Si network using tetraethyl orthosilicate as a silica precursor, and the obtained cryogels were characterized in depth with attenuated total reflectance-Fourier transform infrared spectroscopy, solid-state NMR, X-ray diffraction, thermogravimetric analysis, porosity and swelling tests, Brunauer-Emmett-Teller and Barrett-Joyner-Halenda analyses, frequency sweep and temperature-dependent rheology, contact angle analysis, micromechanical tests, and scanning electron microscopy with energy dispersive X-ray analysis. In addition, the cell survival and osteogenic features of the cryogels were evaluated by the MTS test, live/dead assay, immuno/histochemistry, and quantitative real-time polymerase chain reaction analyses. We conclude that the B-Si-networked Col-HK cryogels having good mechanical durability and osteoinductive features would have the potential bone formation capability. © 2021 American Chemical Society.Öğe Trans-differentiation of human adipose-derived mesenchymal stem cells into cardiomyocyte-like cells on decellularized bovine myocardial extracellular matrix-based films(Springer, 2018) Arslan, Yavuz Emre; Galata, Yusuf Furkan; Arslan, Tugba Sezgin; Derkus, BurakIn this study, we aimed at fabricating decellularized bovine myocardial extracellular matrix-based films (dMEbF) for cardiac tissue engineering (CTE). The decellularization process was carried out utilizing four consecutive stages including hypotonic treatment, detergent treatment, enzymatic digestion and decontamination, respectively. In order to fabricate the dMEbF, dBM were digested with pepsin and gelation process was conducted. dMEbF were then crosslinked with N-hydroxysuccinimide/1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (NHS/EDC) to increase their durability. Nuclear contents of native BM and decellularized BM (dBM) tissues were determined with DNA content analysis and agarose-gel electrophoresis. Cell viability on dMEbF for 3rd, 7th, and 14th days was assessed by MTT assay. Cell attachment on dMEbF was also studied by scanning electron microscopy. Trans-differentiation capacity of human adipose-derived mesenchymal stem cells (hAMSCs) into cardiomyocyte-like cells on dMEbF were also evaluated by histochemical and immunohistochemical analyses. DNA contents for native and dBM were, respectively, found as 886.11 +/- 164.85 and 47.66 +/- 0.09 ng/mg dry weight, indicating a successful decellularization process. The results of glycosaminoglycan and hydroxyproline assay, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), performed in order to characterize the extracellular matrix (ECM) composition of native and dBM tissue, showed that the BM matrix was not damaged during the proposed method. Lastly, regarding the histological study, dMEbF not only mimics native ECM, but also induces the stem cells into cardiomyocyte-like cells phenotype which brings it the potential of use in CTE.Öğe Xenogenic Neural Stem Cell-Derived Extracellular Nanovesicles Modulate Human Mesenchymal Stem Cell Fate and Reconstruct Metabolomic Structure(Wiley-V C H Verlag Gmbh, 2022) Derkus, Burak; Isik, Melis; Eylem, Cemil Can; Ergin, Irem; Camci, Can Berk; Bilgin, Sila; Elbuken, CaglarExtracellular nanovesicles, particularly exosomes, can deliver their diverse bioactive biomolecular content, including miRNAs, proteins, and lipids, thus providing a context for investigating the capability of exosomes to induce stem cells toward lineage-specific cells and tissue regeneration. In this study, it is demonstrated that rat subventricular zone neural stem cell-derived exosomes (rSVZ-NSCExo) can control neural-lineage specification of human mesenchymal stem cells (hMSCs). Microarray analysis shows that the miRNA content of rSVZ-NSCExo is a faithful representation of rSVZ tissue. Through immunocytochemistry, gene expression, and multi-omics analyses, the capability to use rSVZ-NSCExo to induce hMSCs into a neuroglial or neural stem cell phenotype and genotype in a temporal and dose-dependent manner via multiple signaling pathways is demonstrated. The current study presents a new and innovative strategy to modulate hMSCs fate by harnessing the molecular content of exosomes, thus suggesting future opportunities for rSVZ-NSCExo in nerve tissue regeneration.
