Researcher:
Bozüyük, Uğur

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PhD Student

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Uğur

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Bozüyük

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Bozüyük, Uğur

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Now showing 1 - 6 of 6
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    Publication
    Biosensing–drug delivery systems for in vivo applications
    (Elsevier, 2019) Erkoc, Pelin; N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Akolpoğlu, Mükrime Birgül; Bozüyük, Uğur; Kızılel, Seda; Master Student; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 28376
    Early detection of diseases can increase the efficiency of therapies. Recent advances in biosensor technology have led to the development of accurate and robust systems that can sense disease-dependent changes in analyte. These advancements have enabled faster diagnosis and treatment for various diseases. The invention of smart-responsive materials has opened new gates for next-generation biosensors, which can release the therapeutic payload upon environmental changes. These integrated systems provide increased therapeutic efficacy with reduced side effects, and a better perspective for biomedical applications. With further efforts, including comprehensive research and computational modeling, biosensing–drug delivery systems may become powerful tools for the treatment of chronic diseases.
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    Publication
    Calcification resistance of polyisobutylene and polyisobutylene-based materials
    (Wiley, 2019) Kekeç, Nur Çiçek; Nugay, Nihan; Nugay, Turgut; Kennedy, Joseph P.; N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Akolpoğlu, Mükrime Birgül; Bozüyük, Uğur; Kızılel, Seda; Master Student; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 28376
    Calcification of implanted biomaterials is highly undesirable and limits clinical applicability. Experiments were carried out to assess the calcification resistance of polyisobutylene (PIB), PIB-based polyurethane (PIB-PU), PIB-PU reinforced with (CH3)(3)N+CH2CH2CH2NH2 I--modified montmorillonite (PIB-PU/nc), PIB-based polyurethane urea (PIB-PUU), PIB-PU containing S atoms (PIBS-PU), PIBS-PU reinforced with (CH3)(3)N+CH2CH2CH2NH2 I--modified montmorillonite (PIBS-PU/nc), and poly(isobutylene-b-styrene-b-isobutylene) (SIBS), relative to that of a clinically widely implanted polydimethylsiloxane (PDMS)-based PU, Elast-Eon (the "control"). Samples were incubated in simulated body fluid for 28 days at 37 degrees C, and the extent of surface calcification was analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and Fourier-transform-infrared (FT-IR) spectroscopy. Whereas the PDMS-based PU showed extensive calcification, PIB and PIB-PU containing 72.5% PIB, ie, a polyurethane whose surface is covered with PIB, were free of calcification. PIBS-PU and PIB-PUU, ie, polyurethanes that contain S or urea groups, respectively, were slightly calcified. The amine-modified montmorillonite-reinforcing agent reduced the extent of calcification. SIBS was found slightly calcified. Evidently, PIB and materials fully coated with PIB are calcification resistant.
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    Publication
    Light-triggered drug release from 3D-printed magnetic chitosan microswimmers
    (Amer Chemical Soc, 2018) Yasa, Oncay; Yasa, Immihan Ceren; Ceylan, Hakan; Sitti, Metin; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Bozüyük, Uğur; Kızılel, Seda; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; College of Engineering; N/A; 28376
    Advances in design and fabrication of functional micro/nanomaterials have sparked growing interest in creating new mobile microswimmers for various healthcare applications, including local drug and other cargo (e.g., gene, stem cell, and imaging agent) delivery. Such microswimmer-based cargo delivery is typically passive by diffusion of the cargo material from the swimmer body; however, controlled active release of the cargo material is essential for on-demand, precise, and effective delivery. Here, we propose a magnetically powered, double-helical microswimmer of 6 pm diameter and 20 pm length that can on-demand actively release a chemotherapeutic drug, doxorubicin, using an external light stimulus. We fabricate the microswimmers by two-photon-based 3D printing of a natural polymer derivative of chitosan in the form of a magnetic polymer nanocomposite. Amino groups presented on the microswimmers are modified with doxorubicin by means of a photocleavable linker. Chitosan imparts the microswimmers with biocompatibility and biodegradability for use in a biological setting. Controlled steerability of the microswimmers is shown under a 10 mT rotating magnetic field. With light induction at 365 nm wavelength and 3.4 X 10(-1) W/cm(2) intensity, 60% of doxorubicin is released from the microswimmers within 5 min. Drug release is ceased by controlled patterns of light induction, so as to adjust the desired release doses in the temporal domain. Under physiologically relevant conditions, substantial degradation of the microswimmers is shown in 204 h to nontoxic degradation products. This study presents the combination of light-triggered drug delivery with magnetically powered microswimmer mobility. This approach could be extended to similar systems where multiple control schemes are needed for on-demand medical tasks with high precision and efficiency.
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    Publication
    Recent advances in the design of implantable insulin secreting heterocellular islet organoids
    (Elsevier Sci Ltd, 2021) Sousa, Ana Rita; Oliveira, Mariana B.; Mano, Joao F.; N/A; N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Akolpoğlu, Mükrime Birgül; İnceoğlu, Yasemin; Bozüyük, Uğur; Kızılel, Seda; Master Student; Master Student; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 28376
    Islet transplantation has proved one of the most remarkable transmissions from an experimental curiosity into a routine clinical application for the treatment of type I diabetes (T1D). Current efforts for taking this technology one-step further are now focusing on overcoming islet donor shortage, engraftment, prolonged islet availability, post-transplant vascularization, and coming up with new strategies to eliminate lifelong immunosuppression. To this end, insulin secreting 3D cell clusters composed of different types of cells, also referred as heterocellular islet organoids, spheroids, or pseudoislets, have been engineered to overcome the challenges encountered by the current islet transplantation protocols. beta-cells or native islets are accompanied by helper cells, also referred to as accessory cells, to generate a cell cluster that is not only able to accurately secrete insulin in response to glucose, but also superior in terms of other key features (e.g. maintaining a vasculature, longer durability in vivo and not necessitating immunosuppression after transplantation). Over the past decade, numerous 3D cell culture techniques have been integrated to create an engineered heterocellular islet organoid that addresses current obstacles. Here, we first discuss the different cell types used to prepare heterocellular organoids for islet transplantation and their contribution to the organoids design. We then introduce various cell culture techniques that are incorporated to prepare a fully functional and insulin secreting organoids with select features. Finally, we discuss the challenges and present a future outlook for improving clinical outcomes of islet transplantation.
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    Publication
    Deep insight into PEGylation of bioadhesive chitosan nanoparticles: sensitivity study for the key parameters through artificial neural network model
    (Amer Chemical Soc, 2018) N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Bozüyük, Uğur; Doğan, Nihal Olcay; Kızılel, Seda; PhD Student; Master Student; Faculty Member; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 28376
    lonically cross-linked chitosan nanoparticles have great potential in nanomedicine due to their tunable properties and cationic nature. However, low solubility of chitosan severely limits their potential clinical translation. PEGylation is a well-known method to increase solubility of chitosan and chitosan nanoparticles in neutral media; however, effect of PEG chain length and chitosan/PEG ratio on particle size and zeta potential of nanoparticles are not known. This study presents a systematic analysis of the effect of PEG chain length and chitosan/PEG ratio on size and zeta potential of nanoparticles. We prepared PEGylated chitosan chains prior to the nanoparticle synthesis with different PEG chain lengths and chitosan/PEG ratios. To precisely estimate the influence of critical parameters on size and zeta potential of nanoparticles, we both developed an artificial neural network (ANN) model and performed experimental characterization using the three independent input variables: (i) PEG chain length, (ii) chitosan/PEG ratio, and (iii) pH of solution. We studied the influence of PEG chain lengths of 2, 5, and 10 kDa and three different chitosan/PEG ratios (25 mg chitosan to 4, 12, and 20 mu moles of PEG) for the synthesis of chitosan nanoparticles within the pH range of 6.0-7.4. Artificial neural networks is a modeling tool used in nanomedicine to optimize and estimate inherent properties of the system. Inherent properties of a nanoparticle system such as size and zeta potential can be estimated based on previous experiment results, thus, nanoparticles with desired properties can be obtained using an ANN. With the ANN model, we were able to predict the size and zeta potential of nanoparticles under different experimental conditions and further confirmed the cell-nanoparticle adhesion behavior through experiments. Nanoparticle groups that had higher zeta potentials promoted adhesion of HEK293-T cells to nanoparticle-coated surfaces in cell culture medium, which was predicted through ANN model prior to experiments. Overall, this study comprehensively presents the PEGylation of chitosan, synthesis of PEGylated chitosan nanoparticles, utilizes ANN model as a tool to predict important properties such as size and zeta potential, and further captures the adhesion behavior of cells on surfaces prepared with these engineered nanoparticles.
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    PublicationOpen Access
    A novel method for PEGylation of chitosan nanoparticles through photopolymerization
    (Royal Society of Chemistry (RSC), 2019) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Bozüyük, Uğur; Gökulu, İpek Simay; Doğan, Nihal Olcay; Kızılel, Seda; PhD Student; Faculty Member; College of Engineering; N/A; N/A; N/A; 28376
    An ultrafast and convenient method for PEGylation of chitosan nanoparticles has been established through a photopolymerization reaction between the acrylate groups of PEG and methacrylated-chitosan nanoparticles. The nanoparticle characteristics under physiological pH conditions were optimized through altered PEG chain length, concentration and duration of UV exposure. The method developed here has potential for clinical translation of chitosan nanoparticles. It also allows for the scalable and fast synthesis of nanoparticles with colloidal stability.