Tracking Nanoparticles Using DNA Barcodes

By Lacey Cirinelli

Imagine being able to deliver a necessary drug directly to sick cells in a patient’s body. Gene therapy is an experimental technique that aims to do just that using genetic material as the “drug.” It’s difficult to control where genes are delivered, so researchers are turning to materials thinner than a human hair for help.

Gene therapy uses DNA or RNA to treat or prevent a disease by replacing a “sick” (mutated) gene with a “healthy” (therapeutic) copy. The gene is carried by a vector, or vehicle, which delivers the gene to the targeted cells. Ideally, a gene therapy vector targets only the necessary cells or organs (i.e. islet cells in the pancreas for diabetes) and can deliver and activate the genetic material without triggering an immune response. Unfortunately, researchers struggle to control which organs take up vectors carrying therapeutic genes, and testing potential vectors is time consuming. 

Tiny Size, Big Potential

Over the past two decades, researchers have developed numerous synthetic particles in an effort to find better gene therapy vectors. One major focus has been nanoparticles, which have a diameter of 100nm or less and are smaller than red blood cells. Typically, new vectors are tested individually in cell culture and then in animals. However, researchers at the University of Florida, Massachusetts Institute of Technology, and Georgia Tech recently developed a more efficient way to simultaneously test multiple nanoparticles using DNA barcodes as localization markers.

In the new method, individual types of nanoparticles are labeled with pieces of DNA before being injected into mice. The DNA snippet acts as a barcode, allowing researchers to examine the animal’s organs and determine which nanoparticles were delivered to a single organ, which entered multiple organs, and which did not enter any organs. Using DNA in this way could allow researchers to test hundreds of different nanoparticles at one time while using as little as three animals per set of nanoparticles.

While the initial results are promising, more work must be done. Only non-toxic nanoparticles that are stable in aqueous solutions were tested, and large DNA strands and active therapeutic genes also still must be examined. However, DNA barcoded nanoparticles could quickly identify which nanoparticle vectors can be delivered most effectively while providing a better understanding of how the body processes nanoparticle vectors during disease.