Open AccessEngineering Plasmonic Nanoparticles for Enhanced Photoacoustic Imaging
Author(s) -
Yash Mantri,
Jesse V. Jokerst
Publication year - 2020
Publication title -
acs nano
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.554
H-Index - 382
eISSN - 1936-086X
pISSN - 1936-0851
DOI - 10.1021/acsnano.0c05215
Subject(s) - thermoelastic damping , plasmon , materials science , nanoparticle , plasmonic nanoparticles , thermal expansion , nanorod , absorption (acoustics) , optoelectronics , nanotechnology , optics , thermal , composite material , physics , meteorology
Photoacoustic (PA) imaging is an emerging imaging modality whereby pulsed laser illumination generates pressure transients that are detectable using conventional ultrasound. Plasmonic nanoparticles such as gold nanorods and nanostars are often used as PA contrast agents. The thermoelastic expansion model best describes the PA response from plasmonic nanoparticles: Light absorption causes a small increase in temperature leading to thermoelastic expansion. The conversion of optical energy into pressure waves ( p o ) is dependent on several features: (i) the absorption coefficient (μ a ), (ii) the thermal expansion coefficient (β), (iii) specific heat capacity ( C p ) of the absorbing material, (iv) speed of sound in the medium (c), and (v) the illumination fluence ( F ). Controlling the geometry, composition, coatings, and solvents around plasmonic nanostructures can help tune these variables to generate the optimum PA signal. The thermoelastic expansion model is not limited to plasmonic structures and holds true for all absorbing molecules. Here, we focus on ways to engineer these variables to enhance the PA response from plasmonic nanoparticles.