Molecules could be used to transport medicine to diseased cells.

Researchers have created the first DNA nanorobot (a molecule that can be programed to perform certain tasks) that can hold and release biomolecules, an Aarhus University news release reported. The team hopes this new technology will be used to transport medicine within the body.

The research team (including colleagues from Italy) used DNA self-assembly to design "eight unique DNA molecules from the body's own natural molecules," the news release reported.

When these eight molecules mix they naturally arrange themselves into a nanocage.

The nanocages have four "functional elements" that are directly affected by temperature. The temperature can either close or open the nanocage (see figure below).

The team used the temperature changes to capture an active enzyme, called horseradish peroxidase, (HRP), in the nanocage.

The enzyme is encapsulated in the nanocage's "outer lattice has apertures with a smaller diameter than the central spherical cavity." The structure has the ability to capture a number of molecules that are larger than the nanocage's components as long as it can fit in the central cavity.

The researchers were able to successfully show the nanocage was capable of trapping the enzyme when triggered by temperature changes.

They were also able to show HRP "retains its enzyme activity inside the nanocage and converts substrate molecules that are small enough to penetrate the nanocage to products inside."

The enzyme is not trapped in the nanocage permanently; additional temperature changes open the structure and release the HRP.

"Looking towards the future, the concept behind this nanocage is expected to be used for drug delivery, i.e. as a means of transport for medicine that can target diseased cells in the body in order to achieve a more rapid and more beneficial effect," the news release reported.

The work was published in the journal ACS Nano.