Photoswitchable Molecular Motor Phospholipid: Synthesis, Characterization, and Integration into Lipid Vesicles

Abstract

Lipid membranes are essential for cellular function, acting as barriers and platforms for major cellular and biochemical activities. The integration of photoisomerizable units into lipid structures allows for tunable membrane properties, offering insights into major membrane-related processes. In this study, we present the first molecular-motor-conjugated phospholipid system. The synthesis of two phosphatidylcholine derivatives is reported, where one acyl chain is replaced with a light-responsive molecular rotary motor moiety. We explore the photochemical and thermodynamic behaviors of these compounds in solution and as self-assembled systems, demonstrating their rotation cycles under illumination and their dynamic properties in combination with lipid molecules. Additionally, giant unilamellar vesicles with these compounds are formed to investigate the mechanisms of the photoinduced responses in synthetic lipid membranes. Our findings show that molecular motor-based lipids can operate in aqueous solution and with natural phospholipids, maintaining photoisomerization properties and enabling oxidation-driven release within giant lipid vesicles.