Ever since I read about quantum dots (those nano-sized, fluorescent semiconductor balls that seem to be in many R&D labs), I wondered when the pharma industry would have its chance to put them to use. For the past 10-15 years, it seems like the scientific world marveled over their potential applications. So far, they have found use in cellular imaging, LEDs, and solar cells. Now, it looks like drug delivery may be the next frontier.
Thanks to a team of researchers from the University of Washington (Seattle) and Emory University (Atlanta), quantum dots are now able to carry the gene-silencing tools known as siRNA and inject them into cells. Delivery of siRNA would block the cells’ production of unwanted protein that would hinder the spread of diseases such as cancer. Their novel technique is also less toxic to the cell than traditional chemical methods.
The problem with siRNA in trying to penetrate the cell wall is that the siRNA complexes have a negative charge. The research team enveloped the quantum dots in what they call “proton sponges” that give the siRNA complex a weaker charge and allow it to settle in the cellular fluid.
As a bonus, the fluorescent quantum dots allow scientists to actually track, for hours at a time, the siRNA as it moves to and in the cell. What is especially unique is that the quantum dots emit light in colors that are directly related to their particle size, so researchers can also keep an eye on how these particles change.
The research is still in its infancy, and until FDA approves quantum dots for use in humans, there is much work to be done. For now, the research team says it will work with FDA-approved materials such as nontoxic iron oxide particles and biodegradable polymeric carriers for the siRNA.