Dual Thermo- and Photo-Responsive Micelles Based on Azobenzene-Containing Random Copolymer

Abstract

Amphiphilic random copolymer poly(methacrylamido-azobenzene)-ran-poly(2-hydroxyethylacrylate) (PMAAAB-ran-PHEA) was synthesized via hydrolysis of poly(methacrylamido-azobenzene)-ran-poly[2-((2′-tetrahydropyranyl)oxy)ethylacrylate] (PMAAAB-ran-P(THP-HEA)), which was prepared by conventional radical polymerization. PMAAAB-ran-PHEA micelles were then prepared via dialysis method against water with DMF as solvent. The structure, morphology, size, and low critical solution temperature (LCST) of PMAAAB-ran-PHEA and its micelles were determined by 1H-NMR, GPC, TEM, and DLS. The thermo- and photo-responsive behaviors of the resulting polymer micelles were investigated with Nile red as a fluorescence probe. The results showed that PMAAAB-ran-PHEA micelles were porous or bowl-shaped and its size was 135–150 nm, and its LCST was 55 °C when FMAAAB of the random copolymer was 0.5351; the hydrophobicity of the micellar core was changed reversibly under the irradiation of UV light and visible light without release of Nile red or disruption of micelles; the size and solubilization capacity of the micelles were dependent on temperature, and Nile red would migrate for many times between the water phase and the micelles, and finally increasingly accumulated during the repeated heating and cooling processes.

Nano drugs delivery system: A novel promise for the treatment of atrial fibrillation

“…; external stimuli such as externally applied magnetic fields, electric fields, ultrasonic waves, heating, light, etc. ( 67 – 69 ).…”

Study on Reversible Solubilization by Adjusting Surfactant Properties

“…However, those methods usually require external stimuli, which thus requires analyzing whether external stimuli affect the stability of micelles. There are various candidates that can act as external stimuli [8][9][10][11]: temperature, electrical potential, light, pH, magnetic field, CO 2 concentration, etc. For example, surfactants, including azobenzene, change their properties via irradiation with ultraviolet and visible light [12][13][14].…”