title: Development of a Nonionic Azobenzene Amphiphile for Remote Photocontrol of a Model Biomembrane.
abstract: We report the synthesis and characterization of a simple nonionic azoamphiphile, C12OazoE3OH, which behaves as an optically controlled molecule alone and in a biomembrane environment. First, Langmuir monolayer and Brewster angle microscopy (BAM) experiments showed that pure C12OazoE3OH enriched in the (E) isomer was able to form solidlike mesophase even at low surface pressure associated with supramolecular organization of the azobenzene derivative at the interface. On the other hand, pure C12OazoE3OH enriched in the (Z) isomer formed a less solidlike monolayer due to the bent geometry around the azobenzene moiety. Second, C12OazoE3OH is well-mixed in a biological membrane model, Lipoid s75 (up to 20%mol), and photoisomerization among the lipids proceeded smoothly depending on light conditions. It is proposed that the cross-sectional area of the hydroxyl triethylenglycol head of C12OazoE3OH inhibits azobenzenes H-aggregation in the model membrane; thus, the tails conformation change due to photoisomerization is transferred efficiently to the lipid membrane. We showed that the lipid membrane effectively senses the azobenzene geometrical change photomodulating some properties, like compressibility modulus, transition temperature, and morphology. In addition, photomodulation proceeds with a color change from yellow to orange, providing the possibility to externally monitor the system. Finally, Gibbs monolayers showed that C12OazoE3OH is able to penetrate the highly packing biomembrane model; thus, C12OazoE3OH might be used as photoswitchable molecular probe in real systems.
authors.affiliation: Instituto de Química del Sur (INQUISUR-CONICET), Departamento de Química, Universidad Nacional del Sur , 8000FTN Bahía Blanca, Argentina.
authors.forename: Luciano A
authors.initials: LA
authors.lastname: Benedini
authors.affiliation: Instituto de Química del Sur (INQUISUR-CONICET), Departamento de Química, Universidad Nacional del Sur , 8000FTN Bahía Blanca, Argentina.
authors.forename: M Alejandra
authors.initials: MA
authors.lastname: Sequeira
authors.affiliation: Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional del Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria , X5000HUA Córdoba, Argentina.
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Fanani
authors.affiliation: Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional del Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria , X5000HUA Córdoba, Argentina.
authors.forename: Bruno
authors.initials: B
authors.lastname: Maggio
authors.affiliation: Instituto de Química del Sur (INQUISUR-CONICET), Departamento de Química, Universidad Nacional del Sur , 8000FTN Bahía Blanca, Argentina.
authors.forename: Verónica I
authors.initials: VI
authors.lastname: Dodero
mesh_terms: D001391:Azo Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D010316:Particle Size; D055668:Photochemical Processes; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000737:chemistry*; D013696:Temperature
chemical_list: D001391:Azo Compounds; D013501:Surface-Active Agents; C009850:azobenzene