DNA Robot Kills Cancer Cells

http://www.scientificamerican.com/article.cfm?id=dna-robot-kills-cancer-cells

DNA origami, a technique for making structures from DNA, may be more than just a cool design concept. It can also be used to build devices that can seek out and destroy living cells. [View a "DNA Origami" Slide Show.]

The nanorobots, as the researchers call them, use a similar system to cells in the immune system to engage with receptors on the outside of cells.

"We call it a nanorobot because it is capable of some robotic tasks," says Ido Bachelet, a postdoctoral fellow at Harvard Medical School in Boston, Massachusetts, and one of the authors of the study, which is published in the February 17 issue of Science. Once the device recognizes a cell, he explains, it automatically changes its shape and delivers its cargo.

The researchers designed the structure of the nanorobots using open-source software, called Cadnano, developed by one of the authors--Shawn Douglas, a biophysicist at Harvard's Wyss Institute for Biologically Inspired Engineering. They then built the bots using DNA origami. The barrel-shaped devices, each about 35 nanometers in diameter, contain 12 sites on the inside for attaching payload molecules and two positions on the outside for attaching aptamers, short nucleotide strands with special sequences for recognizing molecules on the target cell. The aptamers act as clasps: once both have found their target, they spring open the device to release the payload.