title: Ultrahigh sensitivity carbon nanotube agents for photoacoustic molecular imaging in living mice.
abstract: Photoacoustic imaging is an emerging modality that overcomes to a great extent the resolution and depth limitations of optical imaging while maintaining relatively high-contrast. However, since many diseases will not manifest an endogenous photoacoustic contrast, it is essential to develop exogenous photoacoustic contrast agents that can target diseased tissue(s). Here we present a novel photoacoustic contrast agent, Indocyanine Green dye-enhanced single walled carbon nanotube (SWNT-ICG). We conjugated this contrast agent with cyclic Arg-Gly-Asp (RGD) peptides to molecularly target the alpha(v)beta(3) integrins, which are associated with tumor angiogenesis. Intravenous administration of this tumor-targeted contrast agent to tumor-bearing mice showed significantly higher photoacoustic signal in the tumor than in mice injected with the untargeted contrast agent. The new contrast agent gave a markedly 300 times higher photoacoustic contrast in living tissues than previously reported SWNTs, leading to subnanomolar sensitivities. Finally, we show that the new contrast agent can detect approximately 20 times fewer cancer cells than previously reported SWNTs.
authors.affiliation: Molecular Imaging Program at Stanford, Department of Radiology and Bio-X Program, Stanford University, Palo Alto, California 94305, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: de la Zerda
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Liu
authors.forename: Sunil
authors.initials: S
authors.lastname: Bodapati
authors.forename: Robert
authors.initials: R
authors.lastname: Teed
authors.forename: Srikant
authors.initials: S
authors.lastname: Vaithilingam
authors.forename: Butrus T
authors.initials: BT
authors.lastname: Khuri-Yakub
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Chen
authors.forename: Hongjie
authors.initials: H
authors.lastname: Dai
authors.forename: Sanjiv Sam
authors.initials: SS
authors.lastname: Gambhir
mesh_terms: D000162:Acoustics; D000818:Animals; D016023:Integrins / Q000737:chemistry; D051379:Mice; D037742:Nanotubes, Carbon; D009842:Oligopeptides / Q000737:chemistry; D010777:Photochemistry
chemical_list: D016023:Integrins; D037742:Nanotubes, Carbon; D009842:Oligopeptides; C047981:arginyl-glycyl-aspartic acid