Enhanced Photosensitivity and Surfactant Resistance in Nanopolymersome Membranes as a Function of Gold Nanoparticle Incorporation

Polymersomes hold great promise as carrier vesicles for the encapsulation and delivery of cargo. Self-assembly of amphiphilic diblock copolymers into spherical vesicles result in two compartments for encapsulation: an aqueous lumen and a bilayer membrane. Herein, it is demonstrated that dodecanethiol-functionalized gold nanoparticles (AuNPs) can be loaded within the hydrophobic region of the bilayer membrane of polybutadiene-b-poly(ethylene oxide) nanopolymersomes as photosensitizers. This is shown to render vesicles responsive to picosecond pulsed irradiation at a wavelength congruent with the localized surface plasmon resonance of the gold nanoparticles. Membrane disruption is demonstrated to scale with laser pulse energy and shows a strong enhancement with nanoparticle incorporation even at the low end of the concentration range. Nanoparticle concentration is also shown to increase polymersome stability in the presence of nonionic surfactants such as polysorbate 20 and ionic surfactants such as sodium dodecyl sulfate. In addition, a comparative analysis is performed between dynamic light scattering and cryo-transmission electron microscopy vesicle size results whereby an inference is made between sample composition and analytical method.