A group of Canadian and Italian scientists has developed a nano-scale "slingshot" that can shoot drugs directly to the part of the body that needs them, thereby speeding up recovery and reducing side-effects.

This idea addresses one of the most taxing problems in medicine: how to kill diseased cells while preserving healthy ones.

'If you can increase the concentration of that drug at the specific location, that drug will be more efficient.' — Prof. Alexis Vallée-Bélisle

Scientists have for many years been working on improving therapies like chemo and radiation on that score, but most efforts have focused on modifying the chemistry rather than altering the delivery of the drug.

"It's all about tuning the concentration of the drug optimally in the body: high concentration where you want it to be active, and low concentration where you don't want to affect other healthy parts," says Prof. Alexis Vallée-Bélisle of the University of Montreal, co-author of the report published this week in Nature Communications.

"If you can increase the concentration of that drug at the specific location, that drug will be more efficient," he told CBC News in an interview.

'Like a weapon'

Restricting the movement of the drug also reduces potentially harmful secondary effects on other parts of the body — for instance, the hair loss that can result from toxic cancer treatments, or the loss of so-called good bacteria due to antibiotic use.

The idea of the slingshot is to home in on the target cells at a molecular level.

Vallée-Bélisle and his colleagues from U of M and the University of Rome Tor Vergata say they can build a synthetic strand of DNA just a few nanometres long (a nanometre is one-billionth of a metre) that will activate only when it binds to a specific disease marker it has been programmed to identify, like an antibody.

Prof. Alexis Vallée-Bélisle

Alexis Vallée-Bélisle is a professor at the University of Montreal and heads up the school's Laboratory of Biosensors & Nanomachines. (University of Montreal)

The two ends of the strand anchor themselves to the antibody, stretching the strand taut and catapulting the drug to its target.

"Imagine our slingshot like a weapon, and this weapon is being used by our own antibody," said Vallée-Bélisle, who heads the Laboratory of Biosensors & Nanomachines at U of M. "We design a specific weapon targeting, for example, HIV. We provide the weapon in the body with the bullet — the drug. If the right solider is there, the soldier can use the weapon and shoot the problem."

Equally important: if the wrong soldier is present, the weapon won't be deployed.

So rather than delay treatment for an unidentified infection that could be either viral or bacterial, a patient could receive the medication for both and their body would only use the one it needed.

The approach could work with a wide range of drugs aimed at a variety of diseases — antibodies are produced in response to many different conditions, including viral and bacterial infections, allergy, cancer and autoimmune diseases like Type 1 diabetes and lupus.

And it can be adapted for other types of disease markers.

But Vallée-Bélisle and his team are chemists, not clinicians, and their development is so far only a "proof of principle." They intend to work with doctors and other researchers to figure out which diseases to target and which drugs might work best using this delivery system.