Dr. Anvari and collaborators from UCI and University of Kentucky aim to develop a new approach for laser treatment of port wine stain (PWS) vascular abnormalities. The approach involves intravascular administration of optical micro-particles, fabricated from erythrocytes and doped with indocyanine green, an FDA-approved NIR chromophore, as targets for pulsed near infrared (NIR) laser irradiation. A particularly innovative feature of these micro-particles is that their membrane is enriched with cholesterol to prolong the circulation of the particles. The investigators will use animal models consisting of transgenic mice whose melanin content can be varied in a controllable manner, and the rabbit earlobe to study the photothermal response of the vasculature. Through the proposed studies, Anvari and the team will aim to determine the appropriate radiant exposure levels in skins with various pigmentations, and the maximum window of time over which effective blood vessels photocoagulation can be achieved when using these micro-particles in conjunction with pulsed NIR laser irradiation. The investigators expect that the results obtained under this grant will provide some of the key information needed towards ultimate clinical translation.