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 innovative 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, or mutated, gene with a healthy, or 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 (e.g., 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 few decades, researchers have developed numerous synthetic particles to find better gene therapy vectors. One major focus has been nanoparticles, which have a diameter of 100 nanometers or less and are smaller than red blood cells. Typically, new vectors are tested individually in cell culture and then in animals. However, in 2017, researchers at the University of Florida, Massachusetts Institute of Technology, and Georgia Tech developed a more efficient way to simultaneously test multiple nanoparticles using DNA barcodes as localization markers.

For this study, individual types of nanoparticles were 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 can help researchers test hundreds of different nanoparticles at one time while using as little as three animals per set of nanoparticles.

While the initial results were promising, more work is needed. Only non-toxic nanoparticles that are stable in aqueous solutions were tested, and large DNA strands and active therapeutic genes should also be considered. 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.

Today, DNA barcoding is used in many areas of science, including ecology and agriculture, helping researchers identify and detect species, analyze food samples from various organisms, and monitor food safety.

Content updated by Kylie Wolfe, April 2024.

Discussion Questions

  • Why might a vector that works in cell culture fail in animal studies?
  • Why is it undesirable for a therapeutic gene to be taken up by the wrong cells?