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Öğe Effect of surfactant types on the biocompatibility of electrospun HAp/PHBV composite nanofibers(Springer, 2014) Suslu, A.; Albayrak, A. Z.; Urkmez, A. S.; Bayir, E.; Cocen, U.Bone tissue engineering literature conveys investigations regarding biodegradable polymers where bioactive inorganic materials are added either before or after electrospinning process. The goal is to mimic the composition of bone and enhance the biocompatibility of the materials. Yet, most polymeric materials are hydrophobic in nature; therefore, their surfaces are not favorable for human cellular adhesion. In this sense, modifications of the hydrophobic surface of electrospun polymer fibers with hydrophilic and bioactive nanoparticles are beneficial. In this work, dispersion of hydroxyapatite (HAp), which is similar to the mineral component of natural bone, within biodegradable and biocompatible polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with the aid of a surfactant has been investigated. Non-ionic TWEEN20 and 12-hydroxysteric acid (HSA), cationic dodecyl trimethyl ammonium bromide (DTAB) and anionic sodium deoxycholate and sodium dodecyl sulfate (SDS) surfactants were used for comparison in order to prepare stable and homogenous nanocomposite suspensions of HAp/PHBV for the electrospinning process. Continuous and uniform composite nanofibers were generated successfully within a diameter range of 400-1,000 nm by the mediation of all surfactant types. Results showed that incorporation of HAp and any of the surfactant types strongly activates the precipitation rate of the apatite-like particles and decreases percent crystallinity of the HAp/PHBV mats. Mineralization was greatly enhanced on the fibers produced by using DTAB, HSA, and especially SDS on where also osteoblastic metabolic activity was similarly increased. The produced HAp/PHBV nanofibrous composite scaffolds would be a promising candidate as an osteoconductive bioceramic/polymer composite material for tissue engineering applications.Öğe Hemocompatibility Studies of Layer-By-Layer Polyelectrolyte Complexes for Bio-Based Polymers(Institute of Metals Technology, 2023) Moyo, M.T.G.; Adali, T.; Edebal, O.H.; Bayir, E.; Şendemir, A.Thrombogenesis is an important issue that causes failure in blood-contacting biomedical devices. This study focuses on hemocompatibility studies of novel, blood-contacting, polyelectrolyte complexes (PECs) for biomedical application designs. PEC films were fabricated from bio-based polymers of silk fibroin (SF), chitosan (CH), and sodium alginate (AL) through the solvent-casting method as well as the layer-by-layer (LbL) technique. Characterization was carried out by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). FTIR spectra displayed all the layers’ characteristic peaks of SF, CH, and AL. AFM images indicated that the addition of AL as an outer layer increased the surface roughness. DSC analysis suggested that the best thermal stability was observed with the CH outer layer of PECs. SEM micrograph analysis indicated that the morphologies of the PECs were affected by the inclusion of the clopidogrel bisulfate (CLB). Hemocompatibility properties were investigated by a complete blood count (CBC), prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (APTT), platelet adhesion, erythrocyte morphology analysis, in vitro cholesterol, and albumin level tests. These hemocompatibility analyses demonstrated that the PEC surfaces provide favourable principles to design and develop non-thrombogenic PECs for blood-contacting biomedical applications. © 2023. All Rights Reserved.Öğe Mechanobiology of cells and cell systems, such as organoids(Springer Verlag, 2019) Bayir, E.; Sendemir, A.; Missirlis, Y.F.Organoids are in vitro 3D self-organizing tissues that mimic embryogenesis. Organoid research is advancing at a tremendous pace, since it offers great opportunities for disease modeling, drug development and screening, personalized medicine, as well as understanding organogenesis. Mechanobiology of organoids is an unexplored area, which can shed light to several unexplained aspects of self-organization behavior in organogenesis. It is becoming evident that collective cell behavior is distinctly different from individual cells’ conduct against certain stimulants. Inherently consisting of higher number of degrees of freedom for cell motility and more complex cell-to-cell and cell-to-extracellular matrix behavior, understanding mechanotransduction in organoids is even more challenging compared with cell communities in 2D culture conditions. Yet, deciphering mechanobiology of organoids can help us understand effects of mechanical cues in health and disease, and translate findings of basic research toward clinical diagnosis and therapy. © 2019, International Union for Pure and Applied Biophysics (IUPAB) and Springer-Verlag GmbH Germany, part of Springer Nature.Öğe MEDICINAL HERBS USED IN ANXIETY AND SLEEP DISORDERS(University of Ankara, 2023) Bayir, E.; Elgin, Cebe, G.Objective: Anxiety and sleep disorders are psychiatric diseases that have become increasingly common in our country and in the world in recent years. Individuals with anxiety and sleep disorders tend to seek different complementary therapies in addition to pharmacological treatment, which is the main treatment of their disease It is an inevitable fact that the most frequently used sources among these complementary treatment methods are medicinal herbs. However, the idea that these products may have "less side effects/less damage/more effect" is an important issue that needs to be reviewed. In this review, the medicinal plants used in anxiety and sleep disorders are determined by a detailed literature review in PubMed, Science Direct, Google Scholar, BioMed Central, TUBITAK Ulakbim databases, and to examine the potential mechanisms of action of the most frequently used ones on diseases and to reveal their positive/negative effects. Result and Discussion: When the studies in the literature are evaluated; Despite the abundance of medicinal herbs used in anxiety and sleep disorders, the potential mechanism of action and positive/negative effects of many of them have not been fully revealed. Since the wrong and irrational use of these herbs may lead to worsening of the course of the disease, more researches are needed to examine examine medicinal herbs used in anxiety and sleep disorders. © 2023 University of Ankara. All rights reserved.Öğe Naturally Sourced Ergogenic Supports Used By Athletes(University of Ankara, 2023) Bayir, E.; Cebe, G.E.; Öztürk, B.Objective: Ergogenic aids are substances, practices, or techniques that athletes use to support or improve their physical performance before, during, and after exercise. Although the ergogenic substances examined in this research can be found in the market in various formulations and contents, the most preferred type by athletes in recent years is natural-source ergogenic aids, some of which are also used as food and "considered to be more harmless". Naturally sourced ergogenic aids support the performance of the athlete if the right plant, the right drug, the right product, the right time, the right dose and the appropriate formulation are used. Otherwise, in addition to benefiting from this support used by the athlete, results that may adversely affect his health may ocur. Although sportive performance is a priority for the athlete, it is also reported in the literature that the most important thing is the health of the athlete. Result and Discussion: In this review, it is aimed to determine the natural origin ergogenic aids preferred by the athletes in recent years with a detailed literature review in PubMed, Science Direct, Google Scholar, BioMed Central, TUBITAK Ulakbim databases, and to examine the positive and negative aspects of the most frequently used ones in the light of current data. © 2023 University of Ankara. All rights reserved.Öğe Three-dimensional vascularized self-assembled tumor spheroids(Wiley-Blackwell, 2016) Bayir, E.; Kabadayi, H.; Gorgun, C.; Anil, M.; Iz, S. Gulce; Vatansever, H. S.; Sendemir-Urkmez, A.
