Person: DAĞ, AYDAN
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Publication Open Access Synthesis and Characterization of Biodegradable Amphiphilic Star and Y-Shaped Block Copolymers as Potential Carriers for Vinorelbine(2014-01-01T00:00:00Z) Bahadori, Fatemeh; Dag, Aydan; Durmaz, Hakan; Cakir, Nese; ONYUKSEL, Hayat; Tunca, Ümit; Topcu, Gulacti; Hızal, Gürkan; BAHADORİ, FATEMEH; DAĞ, AYDAN; TOPÇU, GÜLAÇTITwo amphiphilic block copolymers using hydrophobic poly(e-caprolactone) (PCL) and hydrophilic poly(ethylene glycol) (PEG) were successfully synthesized. One of them is an (A-b-B)(4) type star polymer [(PCL-b-PEG)(4)] and the other one is a Y-shaped PEG-(PCL)(2). A star-shaped polymer (PCL-b-PEG)(4) was prepared by ring-opening polymerization (ROP) of epsilon-caprolactone continued by click reaction of (PCL-azide)(4) and PEG-alkyne. The synthesis of Y-shaped PEG-(PCL)(2) block copolymer was carried out via Diels-Alder click reaction of a furan protected maleimide end-functionalized PEG (PEG-MI) with an anthracene end-functionalized PCL following the ROP of epsilon-caprolactone. The characterization of micelles is carried out using both materials in aqueous media as drug delivery vehicles, which showed satisfying results and enhanced the cytotoxic effect of the anti-cancer drug vinorelbine (VLB). However, micelles consisted of Y-shaped unimers were found to be more convenient for delivery of hydrophobic drugs such as VLB because they formed in lower concentration, carrying a higher amount of drugs and owing a monomodal distribution. We concluded that the free tails of hydrophobic chains in Y-shaped block copolymer facilitate the assembly of amphiphilic material in water to form micelles.Publication Metadata only Block-Brush Copolymers via ROMP and Sequential Double Click Reaction Strategy(2011-02-15T00:00:00Z) Dag, Aydan; Sahin, Hatice; Durmaz, Hakan; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANWe report an efficient way, sequential double click reactions, for the preparation of brush copolymers with AB black-brush architectures containing polyoxanorbornene (poly (ONB)) backbone and poly(epsilon-caprolactone) (PCL), poly(methyl methacrylate) (PMMA) or poly(tert-butyl acrylate) (PtBA) side poly(ONB-g-PMMA)-b-poly(ONB-g-PCL) and poly(ONB-g-F tBA)-b-poly(ONB-g-PCL). The living ROMP of ONB affords the synthesis of well-defined poly(ONB-anthracene)(20)-b-Poly (ONB-azide)(5) block copolymer with anthryl and azide pendant groups. Subsequently, well-defined linear alkyne end-functionalized PCL (PCL-alkyne), maleimide end-functionalized PMMA (PMMA-MI) and Pt8A-MI were introduced onto the block copolymer via sequential azide-alkyne and Diels-Alder click reactions, thus yielding block-brush copolymers. The molecular weight of block-brush copolymers was measured via triple detection GPC (TD-GPC) introducing the experimentally calculated dn/dc values to the software. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 886-892, 2011Publication Metadata only Graft Copolymers via ROMP and Diels-Alder Click Reaction Strategy(2010-12-15T00:00:00Z) Durmaz, Hakan; Dag, Aydan; Cerit, Nese; Sirkecioğlu, Okan; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANAnthracene functionalized oxanorbornene monomer and oxanorbornenyl polystyrene (PS) with omega anthracene end functionalized macromonomer were first polymerized via ring opening metathesis polymerization using the first generation Grubbs catalyst in dichloromethane at room temperature and then clicked with maleimide end functionalized polymers poly(ethylene glycol) (PEG) MI poly(methyl methacrylate) (PMMA) MI and poly(tert butyl acrylate) (PtBA) MI in a Diels-Alder reaction in toluene at 120 degrees C to create corresponding graft copolymers poly(oxanorbornene) g PEG poly(oxanorbor nene) g PMMA and graft block copolymers poly(oxanorbor nene) g (PS b-PEG) poly(oxanorbornene) g (PS b-PMMA) and poly(oxanorbornene) g (PS b-PtBA) respectively Diels-Alder click reaction efficiency for graft copolymerization was moni tored by UV-vis spectroscopy The dn/dc values of graft copolymers and graft block copolymers were experimentally obtained using a triple detection gel permeation chromatogra phy and subsequently introduced to the software so as to give molecular weights intrinsic viscosity ([eta]) and hydrodynamic radius (R-h) values (C) 2010 Wiley Periodicals Inc J Polym Sci Part A Polym Chem 48 5982-5991 2010Publication Metadata only Cyclic Homo and Block Copolymers Through Sequential Double Click Reactions(2010-11-15T00:00:00Z) Durmaz, Hakan; Dag, Aydan; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANWell-defined linear alpha-anthracene-omega-maleimide functionalized polystyrene (l-Anth-PS-MI) and linear alpha-alkyne-omega-maleimide functionalized poly(tert-butyl acrylate) (l-alkyne-PtBA-MI) homopolymers, and linear alpha-anthracene-omega-maleimide functionalized PS-b-PtBA (l-Anth-PS-b-PtBA-MI) and linear alpha-anthracene-omega-maleimide functionalized PS-b-poly(epsilon-caprolactone) (PCL) (l-Anth-PS-b-PCL-MI) block copolymers were obtained via combination of atom transfer radical polymerization (ATRP)/ring opening polymerization (ROP) and azide-alkyne click reaction strategy. Subsequently, these linear homo and block copolymers were efficiently clicked via Diels-Alder reaction to give their corresponding cyclic homo and block copolymers at reflux temperature of toluene for 48 h under 7-4 x 10(-5) M conditions. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5083-5091, 2010Publication Metadata only Multiarm Star Block and Multiarm Star Mixed-Block Copolymers via Azide-Alkyne Click Reaction(2010-01-01T00:00:00Z) Durmaz, Hakan; Dag, Aydan; Erdogan, Elif; Demirel, A. Levent; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANThe synthesis of multiarm star block (and mixed-block) copolymers are efficiently prepared by using Cu(I) catalyzed azide-alkyne click reaction and the arm-first approach. alpha-Silyl protected alkyne polystyrene (alpha-silyl-alkyne-PS) was prepared by ATRP of styrene (St) and used as macroinitiator in a crosslinking reaction with divinyl benzene to successfully give multiarm star homopolymer with alkyne periphery. Linear azide end-functionalized poly(ethylene glycol) (PEG-N-3) and poly (tert-butyl acrylate) (PtBA-N-3) were simply clicked with the multiarm star polymer described earlier to form star block or mixed-block copolymers in N,N-dimethyl formamide at room temperature for 24 h. Obtained multiarm star block and mixed-block copolymers were identified by using H-1 NMR, GPC, triple detection-GPC, atomic force microscopy, and dynamic light scattering measurements. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 99-108, 2010Publication Metadata only 3-miktoarm star terpolymers using triple click reactions: Diels-Alder, copper-catalyzed azide-alkyne cycloaddition, and nitroxide radical coupling reactions(2012-02-15T00:00:00Z) Günay, Ufuk Saim; Durmaz, Hakan; Gungor, Eda; Dag, Aydan; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANWell-defined linear furan-protected maleimide-terminated poly(ethylene glycol) (PEG-MI), tetramethylpiperidine-1-oxyl-terminated poly(epsilon-caprolactone) (PCL-TEMPO), and azide-terminated polystyrene (PS-N-3) or -poly(N-butyl oxanorbornene imide) (PONB-N-3) were ligated to an orthogonally functionalized core (1) in a two-step reaction mode through triple click reactions. In a first step, DielsAlder click reaction of PEG-MI with 1 was performed in toluene at 110 degrees C for 24 h to afford alpha-alkyne-alpha-bromide-terminated PEG (PEG-alkyne/Br). As a second step, this precursor was subsequently ligated with the PCL-TEMPO and PS-N-3 or PONB-N-3 in N,N-dimethylformamide at room temperature for 12 h catalyzed by Cu(0)/Cu(I) through copper-catalyzed azide-alkyne cycloaddition and nitroxide radical coupling click reactions, yield resulting ABC miktoarm star polymers in a one-pot mode. (c) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: 729-735, 2012Publication Metadata only Various polycarbonate graft copolymers via Diels-Alder click reaction(2012-11-01T00:00:00Z) Dag, Aydan; Aydin, Mehtap; Durmaz, Hakan; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANIn this work, we used DielsAlder click reaction for the preparation of various types of aliphatic polycarbonates (PCs). We first prepared a novel anthracene-functionalized cyclic carbonate monomer, anthracen-9-ylmethyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate (2), followed by ring-opening polymerization of this monomer to prepare PC with pendant anthracene groups (PC-anthracene) using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/1-(3,5-bis(trifloromethyl)phenyl)-3-cyclohexylthiourea (TU) as the catalyst and benzyl alcohol as the initiator in CH2Cl2 at room temperature. Subsequently, the resulting PC-anthracene (Mn,TDGPC = 6000 g/mol, Mw/Mn = 1.22) was grafted with a linear alpha-furan protected-maleimide terminated-poly(methyl methacrylate) (PMMA-MI) (Mn,GPC = 3100 g/mol, Mw/Mn = 1.31), or poly(ethylene glycol) (PEG-MI) (Mn,GPC = 550 g/mol, Mw/Mn = 1.09), or a mixture of PMMA-MI and PEG-MI to yield well-defined PC graft or hetero graft copolymers, PC-g-PMMA (Mn,TDGPC = 59000 g/mol, Mw/Mn = 1.22) or PC-g-PEG, or PC-g-(PMMA)-co-PC-g-(PEG) (Mn,TDGPC = 39900 g/mol, Mw/Mn = 1.16), respectively, using DielsAlder click reaction in toluene at 110 degrees C. The DielsAlder grafting efficiencies were found to be over 97% using UV spectroscopy. Moreover, the structural analyses and the molecular weights of resulting graft copolymers were determined via 1H NMR and triple detection GPC (TD-GPC), respectively. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012Publication Metadata only Synthesis and characterization of pyrene bearing amphiphilic miktoarm star polymer and its noncovalent interactions with multiwalled carbon nanotubes(2012-06-15T00:00:00Z) Durmaz, Hakan; Dag, Aydan; Tunca, Ümit; Hızal, Gürkan; DAĞ, AYDANA novel amphiphilic miktoarm star polymer, polystyrene-poly(ethylene glycol)-poly(methyl methacrylate), bearing a pyrene group at the end of PS arm (Pyrene-PS-PEG-PMMA) was successfully synthesized via combination of atom transfer radical polymerization and click chemistry. The structure and composition of the amphiphilic miktoarm star polymer were characterized by gel permeation chromatography and 1H NMR. The functionalization of multiwalled carbon nanotubes (MWCNTs) via pp stacking interactions with pyrene-PS-PEG-PMMA miktoarm star polymer was accomplished and the resulting polymer-MWCNTs hybrid was analyzed by using 1H NMR, UVvis, fluorescence spectroscopy, and thermal gravimetric analysis. The high-resolution transmission electron microscopy and analytical techniques aforementioned confirmed that the noncovalent functionalization of MWCNT-s with the amphiphilic miktoarm star polymer was successfully achieved. The MWCNT/pyrene-PS-PEG-PMMA exhibited significant dispersion stability in common organic solvents such as dimethyl formamide, chloroform, and tetrahydrofuran. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012Publication Metadata only An easy way to the preparation of multi-miktoarm star block copolymers via sequential double click reactions(2010-07-01T00:00:00Z) Dag, Aydan; Durmaz, Hakan; Kirmizi, Volkan; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANAs a new synthetic route, we here employed sequential double click reactions involving azide-alkyne and Diels-Alder reactions for the preparation of multi-miktoarm star block copolymers by using the arm-first approach.Publication Metadata only Diels-alder click reaction for the preparation of polycarbonate block copolymers(2013-05-15T00:00:00Z) Omurtag, Pinar Sinem; Günay, Ufuk Saim; Dag, Aydan; Durmaz, Hakan; Hızal, Gürkan; Tunca, Ümit; DAĞ, AYDANThe Diels-Alder reaction as a click reaction strategy is applied to the preparation of well-defined polycarbonate (PC)-block copolymers. A well-defined -anthracene-terminated polycarbonate (PC-anthracene) is prepared using 9-anthracene methanol as an initiator in the ring opening polymerization of benzyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate in CH2Cl2 at room temperature for 5 h. Next, a well-defined -furan protected maleimide-terminated-poly(ethylene glycol) (PEG11-MI or PEG37-MI), -poly(methyl methacrylate) (PMMA26-MI), and -poly(epsilon-caprolactone) (PCL27-MI) were clicked with the PC-anthracene at reflux temperature of toluene to yield their corresponding PC-based block copolymers (PC-b-PEG, PC-b-PMMA, and PC-b-PCL). The homopolymer precursors and their block copolymers were characterized by using the GPC, NMR and UV analysis. (c) 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 2252-2259