Aggregation behaviors and photoresponsive properties of azobenzene constructed phosphate dendrimers

The first to third generation of amphiphilic azobenzene constructed phosphate dendrimers (G0 to G2) was synthesized via a convergent strategy and characterized by NMR and MALDI-TOF-MS measurements. The aggregation behaviors and photoresponsive properties of their aggregates in water were investigated. The TEM observation and UV-vis absorption spectral study showed that the morphologies of the aggregates are greatly affected by the preparation method. The multiple aggregation states, including H-aggregation and J-aggregation, were formed by azobenzene moieties in G1 and G2 aggregates prepared via sonication, which was thought to be due to their different distance from the hydrophilic phosphate group. The controlled release property of G1 vesicle was investigated using calcein as a fluorescence indicator, showing the potential use as a photoregulatable carrier.