title: Engineering optically triggered droplets for photoacoustic imaging and therapy.
abstract: Liquid perfluorocarbon (PFC) droplets incorporating optical absorbers can be vaporized through photothermal heating using a pulsed laser source. Here, we report on the effect of droplet core material on the optical fluence required to produce droplet vaporization. We fabricate gold nanoparticle templated microbubbles filled with various PFC gases (C3F8, C4F10, and C5F12) and apply pressure to condense them into droplets. The core material is found to have a strong effect on the threshold optical fluence, with lower boiling point droplets allowing for vaporization at lower laser fluence. The impact of droplet size on vaporization threshold is discussed, as well as a proposed mechanism for the relatively broad distribution of vaporization thresholds observed within a droplet population with the same core material. We propose that the control of optical vaporization threshold enabled by engineering the droplet core may find application in contrast enhanced photoacoustic imaging and therapy.
authors.affiliation: Department of Mechanical Engineering, University of Colorado Boulder, 427 UCB, Boulder, Colorado 80309, USA.
authors.forename: Jacob D
authors.initials: JD
authors.lastname: Dove
authors.affiliation: Department of Mechanical Engineering, University of Colorado Boulder, 427 UCB, Boulder, Colorado 80309, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Mountford
authors.affiliation: Department of Mechanical Engineering, University of Colorado Boulder, 427 UCB, Boulder, Colorado 80309, USA ; Todd.Murray@colorado.edu.
authors.forename: Todd W
authors.initials: TW
authors.lastname: Murray
authors.affiliation: Department of Mechanical Engineering, University of Colorado Boulder, 427 UCB, Boulder, Colorado 80309, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Borden
keywords: (160.1435) Biomaterials; (170.0170) Medical optics and biotechnology; (170.5120) Photoacoustic imaging; (190.4870) Photothermal effects