Treating cancer is often tricky because doctors want to use drugs strong enough to kill a tumor, but those same drugs can be hard on the rest of the body. While modern treatments like antibody-drug conjugates (ADCs) have helped by acting like a GPS for medicine, they are often too bulky to get deep into a tumor.

Researchers at the University of Geneva (UNIGE) have found a potential fix. Instead of relying on big antibodies, they are using tiny strands of synthetic DNA to build a “smart” delivery system. These DNA strands are small enough to move through dense tumor tissue easily, and they don’t carry the drug in an active state.

Using Logic to Fight Cancer

The system functions like two-factor authentication for your personal information. For example, researchers send in separate DNA strands, with some that carry markers that look for cancer, and others carry the drug. The drug only assembles and activates when it finds two specific cancer markers at the same time.

If the system only finds one marker, or none at all, nothing happens. This protects healthy cells that might share one characteristic with a cancer cell but not both. In lab tests, this “And” logic allowed the drug to hit the target precisely while leaving healthy neighbors alone.

“This could mark an important step forward in the evolution of medicine, with the introduction of a self-operating drug system. Until now, computers and AI have helped us design new drugs,” explained Nicolas Winssinger, a professor at UNIGE and the lead author of the study. “What’s new here is that the drug itself can, in a simple way, ‘compute’ and respond intelligently to biological signals.”

Programmable Medicine

Because these strands are programmable, scientists can swap out different parts to target different types of cancer or even combine multiple drugs at once. This flexibility could be a huge help in stopping tumors from becoming resistant to treatment.

The team views these DNA strands like molecular computers. While this version uses simple “And” logic, future versions could be even more complex. The goal is to create medicine that can make its own decisions inside the body, adapting to a patient’s specific needs in real-time. It’s a move toward a future where the medicine is just as smart as the tools used to design it.