Silica-coated gold nanoplates as stable photoacoustic contrast agents for sentinel lymph node imaging

• Published in: Nanotechnology Vol. 24; no. 45; pp. 455101 - 1-8
• Main Authors: Luke, Geoffrey P, Bashyam, Ashvin, Homan, Kimberly A, Makhija, Suraj, Chen, Yun-Sheng, Emelianov, Stanislav Y
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 15.11.2013; Institute of Physics
• Subjects: Animals; Cell Line, Tumor; Condensed matter: structure, mechanical and thermal properties; Continuous wave lasers; Contrast Media; Cross-disciplinary physics: materials science; rheology; Diagnostic Imaging - methods; Exact sciences and technology; Female; Gold; Humans; Materials science; Metal Nanoparticles - ultrastructure; Mice; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Photoacoustic Techniques; Physics; Radiation effects on specific materials; Sentinel Lymph Node Biopsy - methods; Silicon Dioxide; Spectrophotometry, Ultraviolet; Spectroscopy, Near-Infrared; Structure of solids and liquids; crystallography; Radiation effects; Gold; Nanoplate; Ultrasonic waves; Cytotoxicity; Laser irradiation; Real time; Silica; In vivo; Continuous wave; Tumours; Imaging; Nanostructured materials
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/24/45/455101

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.