DNA nanorobots find and tag cellular targets

Researchers at Columbia University Medical Center, working with their collaborators at the Hospital for Special Surgery, have created a fleet of molecular "robots" that can home in on specific human cells and mark them for drug therapy or destruction.

The nanorobots—a collection of DNA molecules, some attached to antibodies —were designed to seek a specific set of human blood cells and attach a fluorescent tag to the cell surfaces.

"This opens up the possibility of using such molecules to target, treat, or kill specific cells without affecting similar healthy cells," said the study's senior investigator, Milan Stojanovic, PhD, associate professor of medicine and of biomedical engineering at Columbia University Medical Center. "In our experiment, we tagged the cells with a fluorescent marker; but we could replace that with a drug or with a toxin to kill the cell."

Though other DNA nanorobots have been designed to deliver drugs to cells, the advantage of Stojanovic's fleet is its ability to distinguish cell populations that do not share a single distinctive feature. The only way to target cells more precisely is to identify cells based on a collection of features. "If we look for the presence of five, six, or more proteins on the cell surface, we can be more selective," Dr. Stojanovic said. Large cell-sorting machines have the ability to identify cells based on multiple proteins, but until now, molecular therapeutics have not had that capability.