BRET-Based Dual-Color (Visible/Near-Infrared) Molecular Imaging Using a Quantum Dot/EGFP-Luciferase Conjugate.

By virtue of its high sensitivity, bioluminescence imaging (BLI) is an important tool for biosensing and bioimaging in life sciences. Compared to fluorescence imaging (FLI), BLI has a superior advantage that the background signals resulting from autofluorescence are almost zero due to the unnecessity of external excitation. In addition, BLI can permit a long-term observation of living cells because BL results in very low photocytotoxicity toward the host cells. Although BLI has such superior properties over FLI, the available wavelengths in BLI are mostly limited to the visible region. Here we present bioluminescence resonance energy transfer (BRET)-based visible and near-infrared dual-color molecular imaging using a quantum dot (QD) and luciferase-protein conjugate.