title: Self-luminescing BRET-FRET near-infrared dots for in vivo lymph-node mapping and tumour imaging.
abstract: Strong autofluorescence from living tissues, and the scattering and absorption of short-wavelength light in living tissues, significantly reduce sensitivity of in vivo fluorescence imaging. These issues can be tackled by using imaging probes that emit in the near-infrared wavelength range. Here we describe self-luminescing near-infrared-emitting nanoparticles employing an energy transfer relay that integrates bioluminescence resonance energy transfer and fluorescence resonance energy transfer, enabling in vivo near-infrared imaging without external light excitation. Nanoparticles were 30-40 nm in diameter, contained no toxic metals, exhibited long circulation time and high serum stability, and produced strong near-infrared emission. Using these nanoparticles, we successfully imaged lymphatic networks and vasculature of xenografted tumours in living mice. The self-luminescing feature provided excellent tumour-to-background ratio (>100) for imaging very small tumours (2-3 mm in diameter). Our results demonstrate that these new nanoparticles are well suited to in vivo imaging applications such as lymph-node mapping and cancer imaging.
authors.affiliation: Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, Stanford, California 94305-5484, USA.
authors.forename: Liqin
authors.initials: L
authors.lastname: Xiong
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Shuhendler
authors.forename: Jianghong
authors.initials: J
authors.lastname: Rao
mesh_terms: D000818:Animals; D060807:Bioluminescence Resonance Energy Transfer Techniques; D045744:Cell Line, Tumor; D003952:Diagnostic Imaging / Q000379:methods*; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D049449:Luminescence; D008198:Lymph Nodes / Q000473:pathology*; D051379:Mice; D053758:Nanoparticles / Q000648:ultrastructure; D009369:Neoplasms / Q000175:diagnosis* / Q000473:pathology; D011108:Polymers / Q000737:chemistry; D045663:Quantum Dots; D019265:Spectroscopy, Near-Infrared
chemical_list: D011108:Polymers