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TUNCABOYLU, DENIZ CEYLAN

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DENIZ CEYLAN
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TUNCABOYLU
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    Pluronic Based Injectable Smart Gels with Coumarin Functional Amphiphilic Copolymers
    (2022-06-01T00:00:00Z) Alemdar, Mahinur; Tuncaboylu, Deniz Ceylan; Batu, Hatice Kubra; Temel, Binnur; TUNCABOYLU, DENIZ CEYLAN; TEMEL, BİNNUR
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    Şekil Hafızalı ve Kendini Onarabilen Hidrojeller
    (2021-10-08T00:00:00Z) Kılıç, Hüsna; Tuncaboylu, Deniz Ceylan; Argun, Aslı; Öztürk Civelek, Dilek; TUNCABOYLU, DENIZ CEYLAN; ÖZTÜRK CİVELEK, DİLEK
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    Porous rubber cryogels: effect of the gel preparation temperature
    (2014-08-01T00:00:00Z) Oztoprak, Zeynep; Hekimoglu, Tugce; Karakutuk, Ilknur; Tuncaboylu, Deniz C.; Okay, Oğuz; TUNCABOYLU, DENIZ CEYLAN
    This paper examines the effect of the gel preparation temperature (T (prep)) on the physical properties of the rubber-based macroporous organogels prepared by solution crosslinking in benzene at subzero temperatures. Cis-polybutadiene (CBR) and styrene-butadiene rubber (SBR) were used as the rubber components, while sulfur monochloride (S2Cl2) was the crosslinker in the gel preparation. It was shown that T (prep) is an extremely important parameter to adjust the porous structure and thus, the cryogel properties. The networks formed by CBR and SBR showed an aligned porous structure with an exception of honey-comb structured porous SBR cryogels prepared at -2 A degrees C. 10(1)- to 10(2)-mu m sized regular pores of the networks caused by the benzene crystals act as a template during gelation, separated by 10-20 mu m pore walls in thickness. They exhibit fast swelling and deswelling properties as well as reversible swelling-deswelling cycles in toluene and methanol, respectively. The ability of the organogels for the removal of petroleum products from aqueous solutions was also demonstrated using diesel and crude oil as model pollutants. In addition, the reusability of the organogels and their continuous sorption capacities were checked by repeated sorption-squeezing cycles. All the tests showed that the aligned porous organogels are suitable materials for the oil spill cleanup procedures.
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    Structure optimization of self-healing hydrogels formed via hydrophobic interactions
    (2012-11-09T00:00:00Z) Tuncaboylu, Deniz C.; Argun, Aslihan; Sahin, Melahat; Sari, Murat; Okay, Oğuz; TUNCABOYLU, DENIZ CEYLAN
    In an attempt to mimic self-healing functions in biological systems, we investigate here the optimum design parameters of self-healing hydrogels formed by hydrophobic associations in aqueous solutions of wormlike sodium dodecyl sulfate (SDS) micelles. n-alkyl (meth)acrylates were used as the hydrophobic comonomer (2 mol %) of acrylamide in the gel preparation. Two structural parameters are crucial for obtaining self-healing gels via hydrophobic interactions. One is the length of the alkyl side chain of the hydrophobe, and the other is the surfactant concentration. In addition, hydrophobic methacrylates generate gels with a higher healing efficiency than the corresponding acrylates due to the limited flexibility of the methacrylate backbones, leading to a greater number of non-associated hydrophobic blocks. These free blocks locating near the fracture surface of the gel samples link each other to self-heal the broken hydrogel. The physical gels without SDS are very tough due to their sacrificial bonds that are broken under force and preventing the fracture of the molecular backbone. (C) 2012 Elsevier Ltd. All rights reserved.
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    Autonomic self-healing in covalently crosslinked hydrogels containing hydrophobic domains
    (2013-11-01T00:00:00Z) Tuncaboylu, Deniz C.; Argun, Aslihan; Algi, Melek Pamuk; Okay, Oğuz; TUNCABOYLU, DENIZ CEYLAN
    Self-healing hydrogels suffer from low mechanical strength due to their reversible breakable bonds which may limit their use in any stress-bearing applications. This deficiency may be improved by creating a hybrid network composed of a combination of a physical network formed via reversible crosslinks and a covalent network. Here, we prepared a series of hybrid hydrogels by the micellar copolymerization of acrylamide with 2 mol % stearyl methacrylate (C18) as a physical crosslinker and various amounts of N,N--methylenebis(acrylamide) (BAAm) as a chemical crosslinker. Rheological measurements show that the dynamic reversible crosslinks consisting of hydrophobic associations surrounded by surfactant micelles are also effective within the covalent network of the hybrid hydrogels. A significant enhancement in the compressive mechanical properties of the hybrid gels was observed with increasing BAAm content. The existence of an autonomous self-healing process was also demonstrated in hybrid gels formed at low chemical crosslinker ratios. The largest self-healing efficiency in hybrids was observed in terms of the recovered elastic modulus, which was about 80% of the original value. (C) 2013 Elsevier Ltd. All rights reserved.
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    Design of Biocompatible Multifunctional Hydrogels with Stearyl Methacrylate and Vinylpyrrolidone
    (2022-03-01T00:00:00Z) Kilic, Husna; TUNCABOYLU, Deniz Ceylan; Argun, Aslihan; ÖZTÜRK CİVELEK, DİLEK; TUNCABOYLU, DENIZ CEYLAN; ÖZTÜRK CİVELEK, DİLEK
    Biofunctionality and biocompatibility are essential when tissue or organs are supplemented or replaced with a polymer based material. Here, we prepared stearyl methacrylate (SM) and vinylpyrrolidone (VP) based biocompatible SM-x networks with self-healing and shape memory properties. The mole ratios were gradually changed from hydrophilic to hydrophobic units between 10 and 90% to obtain gels meeting the requirements in various potential bioapplications. In addition to having a time-dependent viscoelastic character, the mechanical properties of the gels can be controlled by the amount of SM introduced into the reaction medium. Low SM content gels cannot fully return to their initial modulus values, while the gels formed with concentrations >= 60% are completely reversible due to the dynamic hydrophobic interactions, which is also effective in the self-healing behavior. Moreover, all of the networks can completely recall their permanent shape in seconds. The viability of human skin fibroblast cells, seeded on SM-x hydrogels, closely related to the water contact angle of the structures, was found to be over 82% at all x values. In the light of the findings, the wide range of properties of SM-x gel samples may show significant potential to address needs in a variety of biomedical applications.
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    Dynamics and Large Strain Behavior of Self-Healing Hydrogels with and without Surfactants
    (2012-02-28T00:00:00Z) Tuncaboylu, Deniz C.; Sahin, Melahat; Argun, Aslihan; Oppermann, Wilhelm; Okay, Oğuz; TUNCABOYLU, DENIZ CEYLAN
    Polyacrylamide hydrogels formed via hydrophobic interactions between stearyl groups in aqueous micellar solution of sodium dodecyl sulfate (SDS) present two faces depending on which state they are. The gels containing SDS micelles exhibit, in addition to the fast mode, a slow relaxation mode in dynamic light scattering (DLS) and time-dependent elastic moduli, indicating the temporary nature of the hydrophobic associations having lifetimes of the order of seconds to milliseconds. The gels where SDS had been removed after their preparation behave similar to chemically cross-linked ones with time-independent elastic moduli, a high degree of spatial inhomogeneity, and a single relaxation mode in DLS. Because of this drastic structural change, the physical gels are insoluble in water with a gel fraction close to unity. In surfactant containing gels, a large proportion of physical cross-links dissociate under force, but they do so reversibly, if the force is removed they reform again. The reversible disengagements of the hydrophobic units building the physical cross-links leads to a self-healing efficiency of nearly 100%, while no such healing behavior was observed after extraction of SDS due to the loss of the reversible nature of the cross-linkages.
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    Supramolecular poloxamer-based in situ gels with hyaluronic acid and cyclodextrins
    (2021-01-01T00:00:00Z) Secer, Sevgi; Ceylan Tuncaboylu, Deniz; TUNCABOYLU, DENIZ CEYLAN
    Mechanically enhanced poloxamer (F127)-based injectable hydrogels in the presence of hyaluronic acid (HA) and three types of cyclodextrin (CD) molecules were prepared. With the addition of HA to the F127 system, higher strain values to break down the interactions between the micelles were obtained. The formulations exhibit more frequency-dependent behavior than F127-HA gels with the inclusion of CD molecules. All the F127-HA-CD formulations containing alpha-, beta- and gamma-CD were found in the injectable range and the viscosity values increased considerably when mucin was added to the triple component formulations that prove the mucoadhesive properties of the gels.
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    Microgels from microfluidic templating and photoinduced crosslinking of cinnamylidene acetic acid modified precursors
    (2017-03-01) Tuncaboylu, DENİZ CEYLAN; WISCHKE, C.; STOERMANN, F.; LENDLEIN, A.; TUNCABOYLU, DENIZ CEYLAN
    So far, a number of approaches to synthesize microgel networks have been followed, while only in few cases a detailed control of the network architecture has been possible. Here, the photoinduced [2 + 2] cycloaddition reaction of cinnamylidene acetic acid (CAA) moieties coupled to four-arm star shaped oligo (ethylene glycol) (OEG) precursors was explored for the creation of microgels with defined polymer network structures. Based on a rational solvent selection and precursor dispersion in glass-capillary microfluidics, microgels could be successfully prepared by the proposed synthesis approach. Model reactions confirmed a quantitative network formation. Therefore, compared to common radical polymerization for microgel crosslinking, CAA-dimerization may be an alternative approach particularly when well defined network structures are desired. (C) 2017 Elsevier B.V. All rights reserved.
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    A multifunctional multimaterial system for on-demand protein release
    (2018-08-28) Tuncaboylu, DENİZ CEYLAN; FRIESS, Fabian; WISCHKE, Christian; LENDLEIN, Andreas; TUNCABOYLU, DENIZ CEYLAN
    In order to provide best control of the regeneration process for each individual patient, the release of protein drugs administered during surgery may need to be timely adapted and/or delayed according to the progress of healing/regeneration. This study aims to establish a multifunctional implant system for a local on-demand release, which is applicable for various types of proteins. It was hypothesized that a tubular multimaterial container kit, which hosts the protein of interest as a solution or gel formulation, would enable on-demand release if equipped with the capacity of diameter reduction upon external stimulation. Using devices from poly(epsilon-caprolactone) networks, it could be demonstrated that a shape-memory effect activated by heat or NIR light enabled on-demand tube shrinkage. The decrease of diameter of these shape-memory tubes (SMT) allowed expelling the payload as demonstrated for several proteins including SDF-1 alpha, a therapeutically relevant chemotactic protein, to achieve e.g. continuous release with a triggered add-on dosing (open tube) or an on-demand onset of bolus or sustained release (sealed tube). Considering the clinical relevance of protein factors in (stem) cell attraction to lesions and the progress in monitoring biomarkers in body fluids, such on-demand release systems may be further explored e.g. in heart, nerve, or bone regeneration in the future.