VESOSOME

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The Vesosome, a new multi-compartment structure consisting of drug-loaded liposomes encapsulated within another bilayer, is a promising drug carrier with better retention and stability compared with unilamellar liposomes. The current vesosome preparation takes advantage of the interdigitated phase of saturated lipids, which causes lipid bilayers to form flat, open sheets at low temperature, that close to form large unilamellar vesicles at higher temperatures. During this closure, the interdigitated sheets encapsulate other lipid vesicles or colloidal particles to become the outer membrane of the vesosome. It has been shown that by adding the triblock copolymer to the interdigitated sheets made from dipalmitol-phosphatidylcholine, the vesosomes achieve the proper size for clinical use. Meanwhile, hollow gold nanospheres with absorbance wavelength in the visible and near infrared (NIR) range are good candidates to trigger the release of contents from drug carriers. Vesosomes containing hollow gold nanospheres in their aqueous interior compartments have been verified by cryo electron transmission microscopy. Furthermore, 6-carboxyfluorescein has been encapsulated together with gold spheres to investigate the release from vesosomes irradiated with femetosecond laser pulses. Substantial amounts of carboxyfluorescein were released in response to only a few laser pulses. Our results suggest vesosomes containing hollow gold nanospheres, with large loading capacity, are useful for laser induced delivery of therapeutic agents and other applications of lasers in biological systems.