'Highly programmable' DNA cubes could be used for drug delivery

3D cages made from strands of DNA could be used as a nanotechnology solution for drug delivery.

Cubes of DNA, with molecular tentacles, or chains, attached on each corner, spontaneously create water-repellant carriages that could be used to carry drugs.

In research carried out at McGill University in Canada, lipid-tipped DNA chains attached to DNA cubes folded back inside, creating places for hydrophobic molecules to be carried. The research is detailed in a paper published in Nature Chemistry on 1 September.

Importantly, the drugs are released by snipping off the tentacles. By designing the cages with specific delivery sites in mind, the tentacles could fall off when the cages arrive at the proper location, delivering the drugs to where they are most effective.

The potential for DNA cages in drug delivery partly lies in their ability to form a variety of cell-like stable structures. As a 2013 paper from Universite Bordeaux Segalen noted, "the ability of DNA to form predicatble and complex nano-architectures is virtually unlimited."

"We are able to create DNA cages with any geometry, size or shape, and that's unique among drug delivery vehicles," says Hanadi Sleiman, who led the research. "They are extremely programmable."

Finding novel ways of inducing these cages to carry a cargo and then release it at the appropriate point is currently a very active area of research. This study is the first time molecules that don't actively attach to DNA have been transported inside a DNA cage.

"[Putting molecules] in a DNA cage is difficult as the pore size is very large," says Sleiman.

To solve this problem, the team added altered DNA chains -- dendritic DNA or "D-DNA" -- to each of the corners of a DNA cube. The chains are known as "amphipiles", meaning that that they are attracted to both water and lipids. As the chains themselves have lipids on the ends, they are therefore attracted to each other.

"When there are eight amphiphiles, they engage in an intramolecular "handshake" inside the cube [] this encapsulates small molecules and releases them by DNA recognition," the team note in the paper.

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'Highly programmable' DNA cubes could be used for drug delivery