Development of a Non-Ionic Azobenzene Amphiphile for Remote Photocontrol of a Model Biomembrane

LUCIANO A. BENEDINI; ALEJANDRA SEQUEIRA; MARIA LAURA FANANI; BRUNO MAGGIO; VERÓNICA I. DODERO

JOURNAL OF PHYSICAL CHEMISTRY B - (Print)

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016 vol. 120 p. 4053 - 4063

1520-6106

We report the synthesis and characterization of a simple non-ionic 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 solid-like 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 solid-like monolayer due to the bent geometry around the azobenzene moiety. Second, C12OazoE3OH is wellmixed in a biological membrane model, Lipoids75TM (up to 20 %mol), and photoisomerization among the lipids proceeded smoothly depending on light conditions. It is proposed that the crosssectionalarea of the hydroxyl triethylenglycol head of C12OazoE3OH inhibits azobenzenes Haggregation 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 photo-modulating some properties, like compressibility modulus, transition temperature and morphology. In addition, photomodulation proceeds with acolor change from yellow to orange, providing the possibility to externally monitoring 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.