Lipid bilayers have either one of the three physical phases (liquid-disorder (Ld), liquid-order (Lo), and Solid-order (So) phases). Among them, Lo phase domains are rich in cholesterol and have been recognized as a model of 'lipid rafts'. In this study, cell-sized liposomes (giant unilamellar vesicles, GUVs) that consist of Ld- and Lo-phase domains were prepared, and a novel method to control the phase was explored. As a result, we succeeded in developing surface-engineered plasmonic nanoparticles to control the formation/collapse of the Lo phase domains in the GUVs. The nanoparticles consisted of gold nanorods, which were capable of photothermal heat generation under near-infrared light, and a mutated form of high-density lipoprotein on the surface, the physiological functions of which include cholesterol efflux from the plasma membrane. Our surface-engineered nanomaterials spontaneously induced the Lo-to-So phase transition and optically induced the reverse transition, most likely via cholesterol absorption from and transfer to the GUV membrane, respectively.

  
https://pubs.acs.org/doi/abs/10.1021/acs.langmuir.0c00049