TY - JOUR TI - Temporal control of encapsulant release from nanoparticle loaded polymersomes via single pulse irradiation DO - https://doi.org/doi:10.7282/T3SF30HK PY - 2018 AB - Polymersomes are spherical vesicles that self-assemble from amphiphilic diblock copolymers. Their structure is comprised of a bilayer membrane and an aqueous lumen which have the ability to encapsulate hydrophobic and hydrophilic molecules, respectively. Polymersomes have received significant attention for applications in drug delivery due to their ability to control the time and location of drug release within the body; this is highly desirable in that potential side effects associated with non-specific cytotoxic drugs can be minimized. While a variety of different stimuli to initiate cargo release have been investigated, light is a particularly attractive trigger because it can be minimally damaging yet deeply penetrating at certain wavelengths and intensities. In order to reduce the dosage of light required to initiate membrane disruption, photosensitizers must be incorporated into the system. In this work, hydrophobic gold nanoparticles (AuNPs) are incorporated into the membrane of PBD35-b-PEG20 (polybutadiene(1,2 addition)-b-ethyleneoxide) polymersomes. Photosensitization is brought about by the strong optical absorption associated with the plasmonic nature of the particles and the accompanying photo- and thermal-mechanical phenomena produced upon excitation. Both nanosecond and femtosecond pulsed laser sources, tuned to a wavelength congruent with the localized surface plasmon resonance (SPR) of the incorporated AuNPs, were used to trigger encapsulant release. Herein, the interaction of single pulse laser irradiation on an individual polymersome basis has been explored. Incorporation of AuNPs in the membrane are shown to significantly reduce the rupture threshold energy for both pulse widths when compared to empty membranes. Additionally, irradiation with sub-threshold energies resulted in the formation of membrane pores with encapsulant release occurring over a time frame of two minutes. An analytical model for drug release from circular membrane pores was used to determine effective pore radii in the irradiated vesicles. Preliminary work to scale down the system to the nanoscale for use as a drug delivery system in vivo is also shown. This fundamental study demonstrates the ability to control encapsulant release from photosensitive polymersomes in a highly spatial and temporal manner. KW - Chemistry KW - Nanoparticles KW - Polymers LA - eng ER -