New DNA Nanotechnology Delivers Drug Payloads to Cancer Cells

New research suggests that using a nanorobot may be a promising method to deliver drugs directly to their targets.

Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University have created a DNA-based model using nano-sized probes, or “nanorobots,” that seek cancer cells and cause them to apoptose. This model of cell-targeted cargo drug delivery is the first of its kind.

The scientists designed a nanorobot in a computer program using the DNA origami method, in which complex 2 and 3-dimensional shapes and objects are constructed by folding a long single strand of viral DNA with hundreds of smaller, targeted strands. With this design, the team of researchers created a barrel-like structure with 2 hinges acting as latches. Although the structure resembles a container when closed, the ends of the DNA “barrel” are left open to allow loading of a medication on the side of the structure in a single step.

The latches, or locks, on either side of the nanorobot contain a strand of DNA called an aptamer that can recognize specific target molecules. When the aptamer encounters a target molecule, the DNA unzips and releases a drug dose from within the barrel.

Shawn Douglas, PhD, Wyss Technology Development fellow, and Ido Bachelet, assistant professor in the Faculty of Life Sciences and the Nano-Center at Bar-Ilan University in Israel, tested the nanorobot model containing antibody fragments on leukemia cells. They loaded the nanorobot with drugs that interfere with the growth cycle of cells, and mixed it with both cancerous and healthy red blood cells. After a few days, half of the leukemia cells were destroyed, whereas the healthy cells remained unchanged.

The researchers believe that the nanorobot could also have important implications for other diseases, as the nanorobot mimics the function of white blood cells in the bloodstream by eliminating foreign material. Additionally, the barrel structure is programmable and can target specific cells in distress. According to the Wyss Institute press release,“The DNA nanorobot emulates this level of specificity through the use of modular components in which different hinges and molecular messages can be switched in and out of the underlying delivery system, much as different engines and tires can be placed on the same chassis.”

“We can finally integrate sensing and logical computing functions via complex, yet predictable, nanostructures—some of the first hybrids of structural DNA, antibodies, aptamers, and metal atomic clusters—aimed at useful, very specific targeting of human cancers and T-cells,” noted George Church, PhD, principal investigator on the project and professor of genetics at Harvard Medical School.

For a thorough explanation of the nanorobot’s mechanisms, see the video from Harvard’s Wyss Institute:

DNA nanorobot from Wyss Institute on Vimeo.