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 tackled by using imaging probes that emit in the near-infrared (NIR) wavelength range. Here we describe self-luminescing NIR-emitting nanoparticles employing an energy transfer relay that integrates bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET), enabling in vivo NIR 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 NIR emission. Using these nanoparticles, we successfully imaged lymphatic networks and vasculature of xenografted tumors in living mice. The self-luminescing feature provided excellent tumor-to-background ratio (>100) for imaging very small tumors (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.

A1R–A2AR heteromers coupled to Gs and Gi/0 proteins modulate GABA transport into astrocytes

“…These results complemented and strengthened the evidence for A 1 R-A 2A R heteromerization in nontransfected astrocytes. Evidence for A 1 R-A 2A R heteromers in living tissues awaits further development of the already-available BRET-FRET near-infrared dot technology for in vivo imaging [30], not yet developed for nervous system analysis.…”

A new target ligand Ser–Glu for PEPT1-overexpressing cancer imaging

“…26 Briefly, a solution of tetrahydrofuran (THF) consisting of 60 µg/mL of PS-PEG-COOH, 40 µg/mL of MEH-PPV, and 0.6 µg/mL of NIR775 dye was initially prepared. Under vigorous sonication, each 2.5 mL of the mixture was then quickly dispersed into 5 mL of millipore water.…”

“…26 As outlined in Figure 2, MEH-PPV and near-infrared (NIR) fluorescent dye NIR775 were coated by polystyrene graft ethylene oxide functionalized with carboxyl groups (PS-PEG-COOH) to form NPs via a nanoprecipitation method. Fluorescence resonance energy transfer (FRET) between MEH-PPV and NIR775 could occur, which produced both a MEH-PPV emission peak and a NIR emission peak (Figure 2).…”

Large enhancement of Förster resonance energy transfer on graphene platforms

“…One of the main advantages of using graphene in plasmonics or graphene-based hybrid-plasmonic devices is its tunability by doping or gating [5]. Especially for applications of the Förster resonance energy transfer (FRET) such as in vivo infrared flourescence imaging applications as for example lymph-node mapping and cancer imaging [6,7] graphene plasmonics is highly suitable and can unfold its full strength.…”