title: Supramolecular Amino Acid Based Hydrogels: Probing the Contribution of Additive Molecules using NMR Spectroscopy.
abstract: Supramolecular hydrogels are composed of self-assembled solid networks that restrict the flow of water. l-Phenylalanine is the smallest molecule reported to date to form gel networks in water, and it is of particular interest due to its crystalline gel state. Single and multi-component hydrogels of l-phenylalanine are used herein as model materials to develop an NMR-based analytical approach to gain insight into the mechanisms of supramolecular gelation. Structure and composition of the gel fibres were probed using PXRD, solid-state NMR experiments and microscopic techniques. Solution-state NMR studies probed the properties of free gelator molecules in an equilibrium with bound molecules. The dynamics of exchange at the gel/solution interfaces was investigated further using high-resolution magic angle spinning (HR-MAS) and saturation transfer difference (STD) NMR experiments. This approach allowed the identification of which additive molecules contributed in modifying the material properties.
authors.affiliation: School of Pharmacy, University of East Anglia, Norwich Research Park, NR4 7TJ, UK.
authors.forename: Susana M
authors.initials: SM
authors.lastname: Ramalhete
authors.affiliation: School of Pharmacy, University of East Anglia, Norwich Research Park, NR4 7TJ, UK.|Current address: Department of Drug Form Technology, Faculty of Pharmacy, Wroclaw Medical University, ul. Borowska 211, 50-556, Wroclaw, Poland.
authors.forename: Karol P
authors.initials: KP
authors.lastname: Nartowski
authors.affiliation: School of Pharmacy, University of East Anglia, Norwich Research Park, NR4 7TJ, UK.
authors.forename: Nichola
authors.initials: N
authors.lastname: Sarathchandra
authors.affiliation: Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS, UK.
authors.forename: Jamie S
authors.initials: JS
authors.lastname: Foster
authors.affiliation: School of Pharmacy, University of East Anglia, Norwich Research Park, NR4 7TJ, UK.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Round
authors.affiliation: School of Pharmacy, University of East Anglia, Norwich Research Park, NR4 7TJ, UK.
authors.forename: Jesús
authors.identifier: http://orcid.org/0000-0001-7250-5639
authors.initials: J
authors.lastname: Angulo
authors.affiliation: Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS, UK.
authors.forename: Gareth O
authors.identifier: http://orcid.org/0000-0002-1013-1480
authors.initials: GO
authors.lastname: Lloyd
authors.affiliation: School of Pharmacy, University of East Anglia, Norwich Research Park, NR4 7TJ, UK.
authors.forename: Yaroslav Z
authors.identifier: http://orcid.org/0000-0003-0424-4128
authors.initials: YZ
authors.lastname: Khimyak
mesh_terms: D024361:Amino Acids, Basic / Q000737:chemistry*; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning
chemical_list: D024361:Amino Acids, Basic; D020100:Hydrogels
keywords: NMR spectroscopy; STD NMR; additive molecules; self-assembly; supramolecular chemistry