title: Diffusion and birefringence of bioactive dyes in a supramolecular guanosine hydrogel.
abstract: Transparent self-standing supramolecular hydrogels were readily prepared by the potassium-ion-mediated self-organization of guanosine and 8-bromoguanosine whilst the individual components precipitated within a few hours. VT-NMR spectroscopy showed that bromoguanosine was a superior gelator compared to guanosine. XRD analysis showed that gel formation was caused by stacked G-quartets. AFM analysis revealed dendritic architectures of the nanofibers in the two-component hydrogel network. DSC profiles showed that the hybrid hydrogels underwent sol-gel transition at lower temperature than the pure guanosine and bromoguanosine hydrogels. Interestingly, bioactive dyes, such as rose bengal, rhodamine-6-G, and fluorescein, could be diffused and released in a controlled manner. UV/Vis absorption and fluorescence spectroscopy and CLSM were used to investigate the diffusion behavior of dyes in the hydrogel network. These dyes exhibited strong birefringence in the gel network (0.07-0.1) as a result of the anisotropic organization.
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur Campus, Mohanpur 7412 52, Nadia, West Bengal, India.
authors.forename: Rabindra Nath
authors.initials: RN
authors.lastname: Das
authors.forename: Y Pavan
authors.initials: YP
authors.lastname: Kumar
authors.forename: Sreenivasarao
authors.initials: S
authors.lastname: Pagoti
authors.forename: Avinash J
authors.initials: AJ
authors.lastname: Patil
authors.forename: Jyotirmayee
authors.initials: J
authors.lastname: Dash
mesh_terms: D001718:Birefringence; D004396:Coloring Agents / Q000737:chemistry*; D004058:Diffusion; D006151:Guanosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D015394:Molecular Structure; D011188:Potassium / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D004396:Coloring Agents; D020100:Hydrogels; D006151:Guanosine; C035169:8-bromoguanosine; D011188:Potassium