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A photocleavable membrane component was introduced into synthetic liposomes to achieve light-triggered pinocytosis-like behavior as a potential solution to the feeding requirement in protocell and bottom-up artificial cell systems. Light-triggered pinocytosis was observed in both elongated liposomes, prepared by lipid film hydration, and osmotically stressed spherical vesicles prepared by the pull-down method. Liposomes formed via lipid film hydration consistently underwent pinocytosis in cases of lobed structures or in prolate ellipsoidal structures with aspect ratios ≥2, suggesting that a critical volume-to-surface-area ratio is necessary to drive pinocytosis. When liposomes formed by the pull-down method were osmotically deformed prior to irradiation, an average of 44% exhibited pinocytosis. This light-driven pinocytosis behavior is hypothesized to be due to an asymmetric distribution of photocleavable lipid between the inner and outer leaflet, consistent with the observation that liposomes assembled a...

Photocleavable liposomes were formed in situ through the coupling of an o-nitrobenzyl-containing azide tail precursor and an alkyne-functionalized lysolipid by the copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction. Inclusion of the photolabile o-nitrobenzyl-structure enables control over the permeability and morphology of the liposomes. Photolysis of the o-nitrobenzyl group changes the molecular structure of the photolabile phospholipids, inducing phase transitions and permeability increases in the bilayer membrane, ultimately disrupting the liposome entity.

Synthetic vesicles have a wide range of applications from drug and cosmetic delivery to artificial cell and membrane studies, making simple and controlled formation of vesicles a large focus of the field today. Here, we report the use of the photoinitiated copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction using visible light to introduce spatiotemporal control into the formation of vesicles. Upon the establishment of the spatiotemporal control over vesicle formation, it became possible to adjust initiation conditions to modulate vesicle sizes resulting in the formation of controllably small or large vesicles based on light intensity or giant vesicles when the formation was initiated in flow-free conditions. Additionally, this photoinitiated method enables vesicle formation at a density 400-fold higher than initiation using sodium ascorbate as the catalyst. Together, these advances enable the formation of high-density, controlled size vesicles using low-energy wavelengths while producing enhanced control over the formation characteristics of the vesicle.

Polysulfide network oxidative modification is presented. Fundamental differences between the properties of sufide-based and sulfone-based networks are discussed, and a method for producing the sulfone-based materials from thioether-based materials is developed. Oxidation enables significant mechanical property enhancements of polysulfide materials without any deleterious effects that typically accompany cross-linking polymerizations. Various application examples such as sulfide-containing particle modification and hardening of soft lithography or thiol–ene 3D microprinted objects are also shown.

Photocleavable liposomes were formed