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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    • "Gold nanorods in particular have been targeted as potential contrast agents for PAI due to their strong tunable NIR absorption and enhancement of their photothermal properties which arise from the plasmon resonance effect [34] [35]. For example, near-infrared (NIR) absorbing gold nanocages have been successfully studied as a new class of tracers for photoacoustic sentinel lymph node mapping on a rat model [36]. Furthermore, single-walled carbon nanotubes have also shown promise as molecular contrast agents for the photoacoustic imaging of tumors when functionalized with cyclic Arg-Gly-Asp (RGD) peptides and PEGylated dendrons[9] [37] [38]. "
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    ABSTRACT: Photoacoustic imaging (PAI) is emerging as a key in vivo imaging technique. Endogenous contrast agents alone are insufficient to obtain high contrast images necessitating a need for synthetic exogenous contrast agents. In recent years a great deal of research has been devoted to the development of nanoparticle based contrast agents with little effort on molecular systems. Here we report on the design and evaluation of BODIPY inspired molecular photoacoustic contrast agents (MPACs). Through chemical modification of the established BODIPY fluorophore, increasing its vibrational freedom and appending with non-emissive functionalities, it is demonstrated that the S0-S1 absorbed excitation energy is redirected towards a nonradiative excited-state decay pathway. Optical and photoacoustic characterization of the modified BODIPY MPACs demonstrates a stronger photoacoustic signal compared to the corresponding fluorescent BODIPY probes.
    Proceedings of SPIE - The International Society for Optical Engineering 02/2014; DOI:10.1117/12.2040057 · 0.20 Impact Factor
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    • "Indeed, the large size of gold nanoplates means they have a higher per-particle absorption than nanorods and are well suited for drainage through the lymphatic system [23]. These nanoparticles can be differentiated from the background endogenous absorbers either by observing a relative increase in signal or by performing spectroscopic PA imaging [15] [20] [21]. The methods of localizing contrast agents, however, have limitations which will impede their eventual clinical translation. "
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    ABSTRACT: A biopsy of the first lymph node to which a tumor drains-the sentinel lymph node (SLN)-is commonly performed to identify micrometastases. Image guidance of the SLN biopsy procedure has the potential to improve its accuracy and decrease its morbidity. We have developed a new stable contrast agent for photoacoustic image-guided SLN biopsy: silica-coated gold nanoplates (Si-AuNPs). The Si-AuNPs exhibit high photothermal stability when exposed to pulsed and continuous wave laser irradiation. This makes them well suited for in vivo photoacoustic imaging. Furthermore, Si-AuNPs are shown to have low cytotoxicity. We tested the Si-AuNPs for SLN mapping in a mouse model where they exhibited a strong, sustained photoacoustic signal. Real-time ultrasound and photoacoustic imaging revealed that the Si-AuNPs quickly drain to the SLN, gradually spreading throughout a large portion of the node.
    Nanotechnology 10/2013; 24(45):455101. DOI:10.1088/0957-4484/24/45/455101 · 3.67 Impact Factor
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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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    ABSTRACT: In this paper, PbS semiconductor quantum dots (QDs) with near-infrared (NIR) photoluminescence were synthesized in oleic acid and paraffin liquid mixture by using an easily handled and 'green' approach. Surface functionalization of the QDs was accomplished with a silica and polyethylene glycol (PEG) phospholipid dual-layer coating and the excellent chemical stability of the nanoparticles is demonstrated. We then successfully applied the ultrastable PbS QDs to in vivo sentinel lymph node (SLN) mapping of mice. Histological analyses were also carried out to ensure that the intravenously injected nanoparticles did not produce any toxicity to the organism of mice. These experimental results suggested that our ultrastable NIR PbS QDs can serve as biocompatible and efficient probes for in vivo optical bioimaging and has great potentials for disease diagnosis and clinical therapies in the future.
    Nanotechnology 05/2012; 23(24):245701. DOI:10.1088/0957-4484/23/24/245701 · 3.67 Impact Factor
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