Browsing by Author "Arslan, Elif"

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1960'lı yıllar ve sonrasındaki Türk müziğinin incelenmesi ve Selami Şahin'in Türk müziğindeki rolü
(Bilkent University, 2015) Taşdemir, Bergüzar; Öntaş, Ceren; Arslan, Elif; Ezilmez, Esra; Hayran, İris
Open Access
Collagen peptide presenting nanofibrous scaffold for intervertebral disc regeneration
(American Chemical Society, 2019) Uysal, Özge; Arslan, Elif; Gülseren, Gülcihan; Kılınç, M. C.; Doğan, İ.; Özalp, H.; Çağlar, Y. Ş.; Güler, M. O.; Tekinay, Ayşe B.
Lower back pain (LBP) is a prevalent spinal symptom at the lumbar region of the spine, which severely effects quality of life and constitutes the number one cause of occupational disability. Degeneration of the intervertebral disc (IVD) is one of the well-known causes contributing to the LBP. Therapeutic biomaterials inducing IVD regeneration are promising candidates for IVD degeneration treatments. Here, we demonstrate a collagen peptide presenting nanofiber scaffold to mimic the structure and function of the natural extracellular matrix of the tissue for IVD regeneration. The collagen peptide presenting nanofiber was designed by using a Pro-Hyp-Gly (POG) peptide sequence on a self-assembling peptide amphiphile molecule, which assembled into nanofibers forming scaffolds. Injection of collagen peptide presenting peptide nanofiber scaffold into the degenerated rabbit IVDs induced more glycosaminoglycan and collagen deposition compared to controls. Functional recovery of the tissue was evaluated by degeneration index score, where the bioactive scaffold was shown to provide functional recovery of the IVD degeneration. These results showed that the collagen peptide presenting nanofiber scaffold can prevent the progression of IVD degeneration and provide further functional recovery of the tissue.
Open Access
Design and development of ecm-inspired peptidebased nanostructures for bioengineering and biomedicine
(2017-08) Arslan, Elif
Advances in understanding of cell-matrix interactions and the regulation of cellular behaviors through nanobiotechnological tools have presented new perspectives for regenerative medicine. Peptide amphiphiles have been used as building blocks for development of bioactive synthetic nanofiber scaffolds for regenerative medicine applications. Biocompatibility, tailorable characteristics, and mechanical stability as well as bioactivitiy of these peptide nanostructures make them ideal candidates for biomedical applications. To guide natural cellular activities, biomaterials should provide a microenvironment similar to that experienced by cells under natural conditions. The native extracellular matrix (ECM) not only provides a suitable physical environment but also incorporates the necessary set of biochemical and mechanical signals to ensure the normal function of cells, as well as mediating their differentiation, morphogenesis and homeostasis by providing biological, physical, and chemical recognition signals that can trigger specific interactions with cell surface receptors. In this thesis, different ECM-mimetic peptide nanofiber formulations were designed and developed, which were shown to have superior chondrogenic and therapeutic effect on stem cell differentiation in vitro and cartilage regeneration in vivo. Hence, the synthetic peptide nanomaterials harbor great promise in mimicking specific ECM molecules as therapeutic agents and model systems.
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Lefter Küçükandonyadis’in hayatı ve Türk futbolundaki yeri
(Bilkent University, 2017) Mert, Aysu; Telli, Atakan; Özer, Cem; Arslan, Elif; Özel, Oğul Hasan
Open Access
Protective therapeutic effects of peptide nanofiber and hyaluronic acid hybrid membrane in in vivo osteoarthritis model
(Acta Materialia Inc, 2018) Arslan, Elif; Ekiz, Melis Sardan; Cimenci, Cagla Eren; Can, N.; Gemci, M. H.; Ozkan, H.; Güler, Mustafa O.; Tekinay, Ayse B.
Osteoarthritis (OA) is a condition where tissue function is lost through a combination of secondary inflammation and deterioration in articular cartilage. One of the most common causes of OA is age-related tissue impairment because of wear and tear due to mechanical erosion. Hyaluronic acid-based viscoelastic supplements have been widely used for the treatment of knee injuries. However, the current formulations of hyaluronic acid are unable to provide efficient healing and recovery. Here, a nanofiber-hyaluronic acid membrane system that was prepared by using a quarter of the concentration of commercially available hyaluronic acid supplement, Hyalgan® was used for the treatment of an osteoarthritis model, and Synvisc® which is another commercially available hyaluronic acid containing viscoelastic supplement, was used as a control. The results show that this system provides efficient protection of arthritic cartilage tissue through the preservation of cartilage morphology with reduced osteophyte formation, protection of the subchondral region from deterioration, and maintenance of cartilage specific matrix proteins in vivo. In addition, the hybrid nanofiber membrane enabled chondrocyte encapsulation and provided a suitable culturing environment for stem cell growth in vitro. Overall, our results suggest that this hybrid nanofibrous scaffold provides a potential platform the treatment of OA. Statement of Significance: Osteoarthritis is a debilitating joint disease affecting millions of people worldwide. It occurs especially in knees due to aging, sport injuries or obesity. Although hyaluronic acid-based viscoelastic supplements are widely used, there is still no effective treatment method for osteoarthritis, which necessitates surgical operation as an only choice for severe cases. Therefore, there is an urgent need for efficient therapeutics. In this study, a nanofiber-HA membrane system was developed for the efficient protection of arthritic cartilage tissue from degeneration. This hybrid nanofiber system provided superior therapeutic activity at a relatively lower concentration of hyaluronic acid than Hyalgan® and Synvisc® gels, which are currently used in clinics. This work demonstrates for the first time that this hybrid nanofiber membrane scaffold can be utilized as a potential candidate for osteoarthritis treatment.
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Recep Yazıcıoğlu'nun Erzincan Valiliği süresince şehre katkıları
(Bilkent University, 2020) Kayapınar, Özgenur; Arslan, Elif; Koçak, Batuhan Safa; Pınar, Çağan; Ergovan, İzmir
Recep Yazıcıoğlu Erzincan'ın en başarılı ve tanınan valilerinden biridir. 1980 ve 1990'lı yıllarda Erzincan'da valilik görevini sürdüren Yazıcıoğlu, Erzincan ilinin ekonomik ve sosyal alanlarda kalkınabilmesi için birçok çalışma yürütmüş, ve bu çalışmalar büyük başarılarla sonuçlanarak Türkiye'de oldukça ses getirmiştir. Karakteristik özellikleri, siyasi tutumu ve mesleğindeki yenilikçi yaklaşımlarıyla eşi benzeri görülmemiş bir vali olan Recep Yazıcıoğlu, Erzincan'ı yalnızca kalkındırmamış, aynı zamanda Erzincan ilinde yaşanan sorunları da özveri ve azimle çözebilmiştir. Erzincan valisi olarak görevini sürdürdüğü sırada Yazıcıoğlu şehrin en önemli ulaşım güzergâhlarından biri olan Kemaliye Başpınar Köprüsü'nün yeniden inşasında etkin bir şekilde rol almıştır. Karşısına çıkan tüm engellere rağmen Erzincan ili için çalışmayı sürdüren Recep Yazıcıoğlu, aynı zamanda Erzincan turizminin kalkındırılması adına önemli çalışmalarda bulunmuş ve şehrin tarihi ve doğal güzelliklerini ön plana çıkararak turistlerin ilgisini çekmeyi başarabilmiştir. Yazıcıoğlu'nun eşsiz ve başarılı bir yerel yönetim figürü olmasında kendisinin halka daima yakın olması ve eşitlikçi bir tutum benimsemesinin kayda değer bir önemi bulunmaktadır. Valilik kariyeri boyunca getirdiği birçok yenilik ve elde ettiği birçok başarı sebebiyle "Süper Vali" adıyla anılmaya başlayan Yazıcıoğlu, geçirdiği bir trafik kazası sonucunda hayatını ani bir şekilde kaybetmesinden sonra dahi gelecek valilere örnek olarak gösterilmeye devam etmiştir.
Open Access
Safety of nanomaterials
(John Wiley & Sons, 2016-03-11) Gündüz, Nuray; Arslan, Elif; Güler, Mustafa O.; Tekinay, Ayşe B.; Güler, Mustafa O.; Tekinay, Ayşe B.
This chapter overviews the attempts in understanding the biocompatibility of nanomaterials and provides an account of how these views changed in light of recent findings, with emphasis on the methodology used in nanotoxicology studies. The excretion and clearance of engineered nanomaterials (ENMs) is discussed in the chapter, but it should be noted that cells themselves respond to ENMs by activating their exocytosis mechanisms, thus extruding or degrading ENMs at the subcellular level. Although the in vitro tests previously outlined in the chapter provide means of predicting the behavior of nanomaterials, it is nonetheless possible that unforeseen in vivo effects may occur. As with any material intended for human use, their safety must first and foremost be investigated to sufficient detail, through both in vitro experiments and animal studies, before they can be administered to human patients.
Open Access
Supramolecular peptide nanofiber morphology affects mechanotransduction of stem cells
(American Chemical Society, 2017-08) Arslan, Elif; Koc,, Meryem Hatip; Uysal, Ozge; Dikecoglu, Begum; Topal, Ahmet E.; Garifullin, Ruslan; Ozkan, Alper D.; Dana, A.; Hermida-Merino, D.; Castelletto, V.; Edwards-Gayle, C.; Baday, S.; Hamley, I.; Tekinay, Ayse B.; Güler, Mustafa O.
Chirality and morphology are essential factors for protein function and interactions with other biomacromolecules. Extracellular matrix (ECM) proteins are also similar to other proteins in this sense; however, the complexity of the natural ECM makes it difficult to study these factors at the cellular level. The synthetic peptide nanomaterials harbor great promise in mimicking specific ECM molecules as model systems. In this work, we demonstrate that mechanosensory responses of stem cells are directly regulated by the chirality and morphology of ECM-mimetic peptide nanofibers with strictly controlled characteristics. Structural signals presented on l-amino acid containing cylindrical nanofibers (l-VV) favored the formation of integrin β1-based focal adhesion complexes, which increased the osteogenic potential of stem cells through the activation of nuclear YAP. On the other hand, twisted ribbon-like nanofibers (l-FF and d-FF) guided the cells into round shapes and decreased the formation of focal adhesion complexes, which resulted in the confinement of YAP proteins in the cytosol and a corresponding decrease in osteogenic potential. Interestingly, the d-form of twisted-ribbon like nanofibers (d-FF) increased the chondrogenic potential of stem cells more than their l-form (l-FF). Our results provide new insights into the importance and relevance of morphology and chirality of nanomaterials in their interactions with cells and reveal that precise control over the chemical and physical properties of nanostructures can affect stem cell fate even without the incorporation of specific epitopes.
Open Access
Therapeutic nanomaterials for cartilage regeneration
(John Wiley & Sons, 2016-03-11) Arslan, Elif; Üstün Yaylacı, Seher; Güler, Mustafa O.; Tekinay, Ayşe B.; Güler, Mustafa O.; Tekinay, Ayşe B.
Articular cartilage (AC) is the main focus of this chapter and indeed most cartilage regeneration studies, since it is commonly affected by diseases and traumatic injuries that necessitate its therapeutic regeneration. There are four main approaches for cartilage regeneration: cultured cell implantation, engineered tissue construct implantation, scaffoldless tissue regeneration, and guided tissue regeneration. Cartilage growth, development, and repair are dependent on both biomechanical and biological signals. The most important growth factors used in cartilage regeneration and tissue engineering approaches are the transforming growth factor ß (TGF‐ß) family members, particularly TGF‐ß1 and TGF‐ß3. Overall, new strategies in the field of cartilage regeneration focus on the unique biochemical and physical properties of native cartilage to design novel tissue constructs that are decorated with cartilage‐specific signals and display suitable anatomical geometries and mechanical properties for the treatment of large tissue defects.
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Türkiye'nin ilk ve son yerli üretim viskisi: Ankara Viskisi
(Bilkent University, 2019) Kazancıoğlu, Latifhan; Arslan, Elif; Turan, Muhammet İkbal; Türkeli, Ali Ekber; Vural, Damla
Türkiye, 1960’larda daha içe dönük, yeni bir ekonomik kalkınma modeline dönmek için ilk adımlarını atmaya başladı. Yerli malların tüketimine teşvik, dışarıya döviz akışını azaltmak ve ülkedeki döviz krizini çözmek gibi sebepler doğrultusunda çeşitli alanlarda iyileştirmeler yapılmaya başlandı. Bu durumdan etkilenen bir alan da alkol piyasası oldu. İlk ve son Türk Viskisi olan “Ankara Viskisi” nin de macerası böyle başlamış oldu. Fakat ithal viskilerden pek de bir farkı olmayan Ankara Viskisi’nin yeterli ilgi ve talep görememesi viskinin zamanla üretiminin azaltımasına ve en sonunda da piyasadan kaldırılmasına sebep olmuştur. Bugün Ankara Viskisi, viski severlerin koleksiyonları için nadide bir parça. Bu çalışmada Ankara Viskisi’nin ortaya çıkışından yok oluşuna kadar olan sürecin detaylı bir incelemesi yapılmıştır.