BRIGHT AND SAFER: Self-luminescing nanoparticles use a two-step relay of resonance energy transfer to generate near-infrared emission by an incorporated dye. The emitted long-wavelength near-infrared light is less absorbed and scattered by the body’s tissues than short-wavelength light, helping to overcome the problem of background interference.GEORGE RETSECK
Fluorescence imaging in living animals and people faces a major obstacle—body tissues not only autofluoresce under external illumination with short-wavelength light, but also absorb and scatter the light, creating a lot of background interference.
GEORGE RETSECKSelf-luminescing quantum-dot conjugates overcome this obstacle by a process called bioluminescence resonance energy transfer (BRET). The dots, joined to a bioluminescent protein, harness short-wavelength light energy from the protein to activate their own long-wavelength, near-infrared light emission in a part of the spectrum where background is minimized. However, being made primarily of heavy metals, the dots introduce a different problem: toxicity.
Jianghong Rao and colleagues, the developers of self-luminescing quantum dots, have therefore come up with a safer alternative that utilizes nanoparticles.
Like the quantum dots, these carbon-based polymer nanoparticles are conjugated to a bioluminescent protein, but unlike quantum dots, the particles themselves do not directly emit near-infrared light in response to BRET relayed from the bioluminescent protein. Instead, they emit light in the short-wavelength range. The ...
