Quantum Dots (Qdots)
Quantum Dots or Qdots are semiconductor nanocrystals (10-20nm in
size) that were discovered in the 1980s. QDots fluoresce with sharper
peaks, extremely bright, and resistant to photobleaching. Each crystal’s
structure and size can be finely tuned to maximize conductance which
translates into fluorescence intensity and wavelength shifts.
The size of Qdots make them interesting in biological imaging, as
they can be delivered into cells via transfection. Using optical
slicing, they can be tracked deep within tissue, and their
photostability allows for long-term imaging and real-time tracking. Some
studies have employed QDots within animals for 4 months.
The problem in the early 2000′s was toxicity of these bright
fluorophores in living cells. QDots are CdSe crystals that are highly
toxic under UV illumination. In the absence of radiation, QDots are
essentially inert. More research and uses of QDots will offer better
insight into the applications possible by these bright, stable crystals.