Sujay Ratna ‘21
Major: Biology
Minors: Chemistry and Sociology
Affiliations: Civic Scholars, Honors College
Faculty Mentor: Dr. Julianne Griepenburg, Assistant Professor of Physics
Abstract
Polymersomes are robust, synthetic vesicles that contain both a hydrophilic core and hydrophobic bilayer membrane, providing for stable, dual encapsulation of many molecules within both regions.
While polymersomes assembled from diblock copolymer poly(butadiene)-b– poly(ethylene oxide) (PBD-b-PEO) are typically insensitive to most internal and external stimuli, our lab has demonstrated that hydrophobic gold nanoparticles (AuNPs) can be incorporated into the membrane as photosensitizers rendering them light-responsive to ultrafast irradiation.Polymersomes, like other structures comprised of a bilayer membrane, can also be structurally disrupted through interaction with surfactants. The use of a surfactant is a common experimental technique used to fully rupture vesicles and release the entirety of their hydrophilic cargo. Interestingly, it was noted that polymersomes prepared with AuNPs loaded into the hydrophobic region of the membrane displayed increasing stability against surfactants in a concentration- dependent fashion. Three common surfactants, Triton X-100, Tween 20, and sodium dodecyl sulfate (SDS) were incorporated into samples of polymersomes containing different concentrations of hydrophobic dodecanethiol-functionalized AuNPs. Rupture was detected by a drastic size decrease (150 nm to 5 nm), characterized by dynamic light scattering. It was found that a significantly greater concentration of surfactant was required to rupture vesicles containing greater concentrations of AuNPs in the membrane. While the mechanism for this surfactant resistance is still under investigation, this finding is important as it implies that AuNPs incorporated into polymersomes as photosensitizers can also double as stabilizers for future applications in vivo, e.g., drug delivery.