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Near-Infrared Gold Nanocages as a New Class of Tracers for Photoacoustic Sentinel Lymph Node Mapping on a Rat Model

Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130-4899, USA.
Nano Letters (Impact Factor: 13.59). 01/2009; 9(1):183-8. DOI: 10.1021/nl802746w
Source: PubMed

ABSTRACT This work demonstrated the use of Au nanocages as a new class of lymph node tracers for noninvasive photoacoustic (PA) imaging of a sentinel lymph node (SLN). Current SLN mapping methods based on blue dye and/or nanometer-sized radioactive colloid injection are intraoperative due to the need for visual detection of the blue dye and low spatial resolution of Geiger counters in detecting radioactive colloids. Compared to the current methods, PA mapping based on Au nanocages shows a number of attractive features: noninvasiveness, strong optical absorption in the near-infrared region (for deep penetration), and the accumulation of Au nanocages with a higher concentration than the initial solution for the injection. In an animal model, these features allowed us to identify SLNs containing Au nanocages as deep as 33 mm below the skin surface with good contrast. Most importantly, compared to methylene blue Au nanocages can be easily bioconjugated with antibodies for targeting specific receptors, potentially eliminating the need for invasive axillary staging procedures in addition to providing noninvasive SLN mapping.

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    • "In 2004, Kim et al proved that NIR type II QDs can be used effectively for SLN mapping in large animals and the NIR signals could be detected at a depth of up to 1 cm in the tissue [39]. Subsequently, Song et al used gold nanocages to absorb NIR light for non-invasive SLN detection in photoacoustic imaging [40]. Kim et al used conjugated polymer nanoparticles as probes for real-time in vivo SLN mapping in mouse [41]. "
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