title: Reversible deformation-formation of a multistimuli responsive vesicle by a supramolecular peptide amphiphile.
abstract: A systematic study of the ternary complex formation process for aromatic amino acids using ucurbit[8]uril (CB[8]) and a viologen amphiphile shows that the affinity of the amino acid needs to be higher or in a comparable range to that of CB[8] for the amphiphile in order to form the ternary complex. Based on these observations, a supramolecular peptide amphiphile and its corresponding vesicle are prepared using a peptide containing an azobenzene moiety. The azobenzene group at the N-terminus of the peptide served as the second guest for CB[8]. The vesicles obtained from this peptide amphiphile show response to a number of external triggers. The trans-cis isomerization of the azobenzene group upon irradiation with UV-light of 365 nm leads to the breakdown of the ternary complex and eventually to the disruption of the vesicle. The deformation-reformation of the vesicle can be controlled by illuminating the disrupted solution with light of 420 nm as it facilitates the cis-trans isomerization. Thus, the vesicle showed a controlled and reversible response to UV-light with the ability for manipulation of the formation-deformation of the vesicle by the choice of an appropriate wavelength. The vesicle showed response to a stronger guest (1-adamantylamine) for CB[8], which displaces both the guests from the CB[8] cavity and consequently ruptures the vesicle structure. 2,6-Dihydroxynaphthalene acts as a competitive guest and thereby behaves as another external trigger for replacing the peptide from the CB[8] cavity by self-inclusion to form the ternary complex. Henceforth, it allows retaining the vesicle structure and results in the release of the peptide from the vesicle.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Guwahati, Kamrup, Assam 781039, India. ddas@iitg.ernet.in.
authors.forename: Julfikar Hassan
authors.initials: JH
authors.lastname: Mondal
authors.forename: Sahnawaz
authors.initials: S
authors.lastname: Ahmed
authors.forename: Titli
authors.initials: T
authors.lastname: Ghosh
authors.forename: Debapratim
authors.initials: D
authors.lastname: Das
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D001952:Bridged-Ring Compounds / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry* / Q000528:radiation effects; D009284:Naphthols / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014466:Ultraviolet Rays; D014755:Viologens / Q000737:chemistry; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D001391:Azo Compounds; D001952:Bridged-Ring Compounds; D007093:Imidazoles; D008081:Liposomes; D009284:Naphthols; D010455:Peptides; D013501:Surface-Active Agents; D014755:Viologens; C507198:cucurbit(8)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils; C050642:1,2-dihydroxynaphthalene; C009850:azobenzene