title: Nonlinear contrast enhancement in photoacoustic molecular imaging with gold nanosphere encapsulated nanoemulsions.
abstract: A composite contrast agent, a nanoemulsion bead with assembled gold nanospheres at the interface, is proposed to improve the specific contrast of photoacoustic molecular imaging. A phase transition in the bead's core is induced by absorption of a nanosecond laser pulse with a fairly low laser fluence (∼3.5 mJ/cm2), creating a transient microbubble through dramatically enhanced thermal expansion. This generates nonlinear photoacoustic signals with more than 10 times larger amplitude compared to that of a linear agent with the same optical absorption. By applying a differential scheme similar to ultrasound pulse inversion, more than 40 dB contrast enhancement is demonstrated with suppression of background signals.
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Wei
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Lombardo
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Kjersta
authors.initials: K
authors.lastname: Larson-Smith
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA ; International Laser Center, Moscow State University, Moscow, Russian Federation.
authors.forename: Ivan
authors.initials: I
authors.lastname: Pelivanov
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Camilo
authors.initials: C
authors.lastname: Perez
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Jinjun
authors.initials: J
authors.lastname: Xia
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Matula
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Danilo
authors.initials: D
authors.lastname: Pozzo
authors.affiliation: Departments of Bioengineering and Chemical Engineering, and Applied Physics Lab, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: O'Donnell
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