Twenty Years Later: Why No Clinical Quantum Dot Imaging Labels?
Quantum dots (QDs), semiconductor nanoparticles that fluoresce upon light excitation, were first
introduced for biological imaging in 1998. At the time, QDs were heralded as a revolutionary
product that would transform biological imaging. QDs have narrow emission bandwidths and
broad excitation spectra, enabling multiplexed imaging. Their fluorescence is tunable based on
QD size, permitting precise tuning of emission wavelength, and QDs are more resistant to
photobleaching than their molecular dye counterpoints. Yet, despite 20 years of research, there
are no clinically approved QD products and QDs remain a niche item used in specific research
For the last 10 years, my group has been investigating reasons for the difficulty in translating
this promising technology into practice. QDs are typically synthesized in organic solutions and
must first be modified to render them colloidally stable in biological, aqueous media. We have
identified key challenges in QD fluorescence loss as a result of these transfer processes. We
will discuss the influence of dilution, purification, and buffer exchange on QD aggregation and
quantum yield losses.
To overcome these challenges, we developed a micelle encapsulation strategy that not only
solvates organic QDs, but also improves their fluorescence stability and brightness. Based on
our promising results in the laboratory, we started a company to commercialize these
technologies for clinical use. I will discuss the challenges in starting a company. In addition, I will
discuss methods to scale up batch processes into commercial scale manufacturing processes
and the differences between research and development. This talk will thus describe the journey
of one idea from conception to realization.