Theranostics 2014; 4(1):36-46. doi:10.7150/thno.7143 This issue
1. Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA 78712;
2. Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, TX, USA 78712;
3. Department of Pathology, University of Alabama Birmingham, Birmingham, AL, USA 35249.
Recently, combined intravascular ultrasound and photoacoustic (IVUS/IVPA) imaging has been demonstrated as a novel imaging modality capable of visualizing both morphology (via IVUS) and cellular/molecular composition (via IVPA) of atherosclerotic plaques, using both endogenous tissue absorbers and exogenous contrast agents. Plasmonic gold nanoparticles were previously utilized as IVPA contrast agents which co-localize with atherosclerotic plaques, particularly phagocytically active macrophages. The present work demonstrates the use of IVUS/IVPA imaging as a tool for localized temperature monitoring during laser heating. The temperature dependent change in IVPA signal intensity of silica-coated gold nanorod contrast agents absorbing within the near-infrared optical wavelength range is evaluated and shown to have a linear relationship, with a slope greater than that of endogenous tissue. A continuous wave laser was subsequently incorporated into the IVUS/IVPA integrated catheter and utilized to selectively heat the nanoparticles with simultaneous IVPA temperature monitoring. IVUS/IVPA, therefore, provides a platform for detection and temperature monitoring of atherosclerotic plaques through the selective heating of plasmonic gold nanoparticle contrast agents.
Keywords: photoacoustic, atherosclerosis, gold nanorods, photothermal, temperature monitoring, intravascular.