01683nas a2200205   4500008004100000022001400041245011400055210006900169260007100238300001400309490000800323520088500331100001801216700002001234700001601254700002701270700002201297700002601319856013201345       2012                        eng d  a0002-786300aMultiple topologies from glycopolypeptide-dendron conjugate self-assembly: nanorods, micelles, and organogels0 aMultiple topologies from glycopolypeptidedendron conjugate selfa  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR  a7796-78020 v1343 a<p>Glycopolypeptides (GPs) were synthesized by ring-opening polymerization of glycosylated N-carboxyanhydride monomer and attached to hydrophobic dendrons at one chain end by ``click'' reaction to obtain amphiphilic anisotropic macromolecules. We show that by varying polypeptide chain length and dendron generation, an organogel was obtained in dimethylsulfoxide, while nanorods and micellar aggregates were observed in aqueous solutions. Assemblies in water were characterized by electron microscopy and dye encapsulation. Secondary structure of the GP chain was shown to affect the morphology, whereas the chain length of the poly(ethylene glycol) linker between the GP and dendron did not alter rod-like assemblies. Bioactive surface chemistry of these assemblies displaying carbohydrate groups was demonstrated by interaction of mannose-functionalized nanorods with ConA.</p>1 aPati, Debasis1 aKalva, Nagendra1 aDas, Soumen1 aKumaraswamy, Guruswamy1 aGupta, Sayam, Sen1 aAmbade, Ashootosh, V.  uhttps://library.ncl.res.in/content/multiple-topologies-glycopolypeptide-dendron-conjugate-self-assembly-nanorods-micelles-and-001765nas a2200229   4500008004100000022001400041245012100055210006900176260007700245300001400322490000800336520087100344653002301215653003201238653001301270653002301283653003301306100002001339700002101359700002601380856012901406       2014                        eng d  a1022-135200aEffect of the branching pattern of hydrophobic dendrons on the core structure of linear-dendritic copolymer micelles0 aEffect of the branching pattern of hydrophobic dendrons on the c  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcAUG  a1456-14650 v2153 a<p>Hydrophobic dendrons based on different branching patterns, viz. 3,5-di- and 3,4,5-trisubstituted phenyl rings, consist of the same backbone but exhibit different sizes, shapes, and hydrophobic densities. These dendrons are attached to poly(ethylene glycol) and the core properties of the copolymer micelles are investigated in tetrahydrofuran (THF)/water mixtures by neutron scattering. Two polymers with intermediate hydrophobicity are studied further with variations in the solvent composition and the temperature. The aggregation numbers for 3,4,5-based dendron copolymers are lower, with more THF molecules of solvation compared with the 3,5-based dendron copolymer, the difference being greater at higher generations due to different molecular shapes. The micellar core size increases in small steps with dendron size so that dye encapsulation is tuned.</p>10adiblock copolymers10alinear-dendritic copolymers10amicelles10aneutron scattering10astructure-property relations1 aKalva, Nagendra1 aAswal, Vinod, K.1 aAmbade, Ashootosh, V.  uhttps://library.ncl.res.in/content/effect-branching-pattern-hydrophobic-dendrons-core-structure-linear-dendritic-copolymer-001994nas a2200169   4500008004100000022001400041245009700055210006900152260011000221300001400331490000600345520127700351100002001628700002001648700002601668856013001694       2015                        eng d  a1759-995400aControlled micellar disassembly of photo- and pH-cleavable linear-dendritic block copolymers0 aControlled micellar disassembly of photo and pHcleavable lineard  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAUG  a6826-68350 v63 a<p>A linear-dendritic block copolymer with both photo-and pH-cleavable linkages at the junction between the hydrophobic dendron and hydrophilic linear polymer was synthesised. The photocleavable o-nitrobenzyl group attached to alkyne was introduced at the focal point of polyester dendron and acid-degradable acetal linkage with terminal azide was introduced at one end of linear polyethylene glycol. The two segments were connected using click chemistry. The copolymer was found to self-assemble into micelle-like aggregates in dilute aqueous solution. Stimuli-responsive disassembly of the aggregates was studied by monitoring fluorescence emission of the encapsulated hydrophobic dye and dynamic light scattering (DLS). Products of acetal cleavage at acidic pH were analyzed by gel permeation chromatography and NMR spectroscopy. The photo and pH stimuli were applied separately as well as simultaneously to study the rate of dye release. The synergistic effect of the two stimuli on dye release was demonstrated and the non-cytotoxic nature of the polymer was shown using the MTT assay. Cell uptake of DOX-loaded micelles and photo-induced release of the drug resulting in significantly higher cytotoxicity than by free DOX was demonstrated using MDA-MB-231 cells.</p>1 aKalva, Nagendra1 aParekh, Nimisha1 aAmbade, Ashootosh, V.  uhttps://library.ncl.res.in/content/controlled-micellar-disassembly-photo-and-ph-cleavable-linear-dendritic-block-copolymers-002081nas a2200169   4500008004100000022001400041245017800055210006900233260011000302300001600412490000600428520128300434100002001717700002401737700002601761856012401787       2016                        eng d  a2046-206900aPhotoresponsive assemblies of linear-dendritic copolymers containing azobenzene in the dendron interior: the effect of the dendron structure on dye encapsulation and release0 aPhotoresponsive assemblies of lineardendritic copolymers contain  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAPR  a43163-431700 v63 a<p>Hydrophobic dendrons with different numbers and positions of azobenzenes as well as different groups benzyl and dodecyl, on the periphery were synthesised and attached to poly(ethylene glycol) using copper-catalysed azide-alkyne cycloaddition to obtain linear-dendritic copolymers. Self-assembly of the polymers in aqueous solution was characterised using dynamic light scattering (DLS), transmission electron microscopy (TEM) and critical micelle concentration (cmc). Formation of H-aggregates during micellisation was shown for polymers with a higher number of azobenzene units. Photoisomerisation of azobenzene in the assemblies was studied and the rate constant of thermal photoisomerisation was calculated. Release of hydrophobic dye Nile red upon photoisomerisation of azobenzene occurred without disruption of micellar aggregates. Dye release varied with the pathway - thermal or visible light irradiation, followed for cis-trans isomerisation. The encapsulation capacity of the micelles and extent of dye release in either pathway were found to be influenced by the dendron structure. A polymer with a lower number of azobenzenes and aliphatic periphery on the dendron showed significantly different behaviour than polymers with a larger number of aromatic units.</p>1 aKalva, Nagendra1 aBasutkar, Nitin, B.1 aAmbade, Ashootosh, V.  uhttps://library.ncl.res.in/content/photoresponsive-assemblies-linear-dendritic-copolymers-containing-azobenzene-dendron01877nas a2200145   4500008004100000245015800041210006900199260000800268300001400276490000700290520125800297100002001555700002601575856013001601       2017                        eng d00aSynthesis and tunable thermoresponsive solution morphologies of 2,2-bis-methylolpropionic acid dendron-azobenzene-poly(N-isopropyl acrylamide) copolymers0 aSynthesis and tunable thermoresponsive solution morphologies of   cJUL  a1084-10930 v663 aAmphiphilic temperature- and photoresponsive linear-dendritic block copolymers comprising second-generation acetonide-2,2-bis-methylolpropionic acid-based polyester dendron and linear poly(N-isopropyl acrylamide) (PNIPAM) linked by an azobenzene unit were synthesized using atom transfer radical polymerization (ATRP) followed by click chemistry. Linear PNIPAM precursor was prepared from an azide-functionalized azobenzene containing ATRP initiator. Two polymers obtained by varying the chain length of the PNIPAM block showed different morphologies and lower critical solution temperature (LCST) values in aqueous solution. Complete change in morphology of the two polymers into large spherical aggregates and nanotubes, respectively, was observed upon heating the micellar solution above LCST. The azobenzene unit was found to undergo trans-cis photoisomerization in the assemblies and caused a change in the microenvironment of an encapsulated hydrophobic dye without any release. Acetonide groups on the dendron were deprotected to afford hydroxylated polymer that showed well-defined morphologies above the LCST and after heating-cooling cycle while significant dye encapsulation was seen only above the LCST. (c) 2017 Society of Chemical Industry1 aKalva, Nagendra1 aAmbade, Ashootosh, V.  uhttps://library.ncl.res.in/content/synthesis-and-tunable-thermoresponsive-solution-morphologies-22-bis-methylolpropionic-acid