Molecular photoacoustic imaging using gold nanoparticles as a contrast agent
Gold nanoparticles have received much attention due to their potential diagnostic and therapeutic applications. Gold nanoparticles are attractive in many biomedical applications because of their biocompatibility, easily modifiable surfaces for targeting, lack of heavy metal toxicity, wide range of sizes (35-100 nm), tunable plasmonic resonance peak, encapsulated site-specific drug delivery, and strong optical absorption in the near-infrared regime. Specifically, due to their strong optical absorption, gold nanoparticles have been used as a contrast agent for molecular photoacoustic (PA) imaging of tumor. The plasmonic resonance peak of the gold nanocages (AuNCs) was tuned to the near-infrared region, and the ratio of the absorption cross-section to the extinction cross-section was approximately ~70%, as measured by PA sensing. We used PEGylated gold nanocages (PEG-AuNCs) as a passive targeting contrast agent on melanomas. After 6-h intravenous injection of PEG-AuNCs, PA amplitude was increased by ~14 %. These results strongly suggest PA imaging paired with AuNCs is a promising diagnostic tool for early cancer detection.
Additional Information© 2010 Society of Photo-Optical Instrumentation Engineers (SPIE). This work was supported in part by grants from National Institutes of Health (R01 EB000712, R01 EB008085, and U54 CA136398 -- the Network for Translational Research -- to L.V.W.). L.V.W. has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work. Y.X. thanks the National Institutes of Health for a 2006 Director's Pioneer Award (DP1 OD000798-04). E.C.C. was also partially supported by a fellowship award from the Korea Research Foundation (KRF-2007-357-D00070) funded by the Korean Government. J.C. was supported by a Pilot Grant from Washington University Molecular Imaging Center.
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