Built from DNA, robots may deliver medicine where no doctor has gone before.
Medical nanorobots may soon be leaving the Petri dish and making their way to a drugstore near you. A team of researchers from the Harvard Wyss Institute for Biologically Inspired Engineering has created a DNA-based nanorobot that can safely carry molecule-sized payloads, detect cancer, and attack that cancer with medicine.
The bot itself is less of a drone and more of a complex piece of fabric. Hundreds of short, single-stranded DNA pieces wrap themselves around a scaffold, “like the warp and weftin weaving cloth,” according to researcher Shawn Douglas.
The mechanism for depositing the payload isn’t an electronic actuator, as you would find in a conventional robot, but a chemical reaction. When the nanobots meet up with a particular protein that can indicate cancer (in their experiment, Douglas and his team used a leukemic cell marker), the nanostructure unlocks itself and releases a cancer-fighting antigen. The process is similar to the way viruses attack cells; the primary difference is that Douglas’s nanobots don’t hijack the cell to reproduce, as natural viruses do.
“Viruses (made of various combinations of protein, nucleic acids, and lipids) offer a good template for what materials work for performing complex interactions and manipulations of cells,” said Douglas in an e-mail.
The research follows (but does not necessarily build upon) the work of New York University chemistry professor Nadrian Seeman, credited with pioneering the field of DNA-based nanostructures to perform complicated tasks.
But do these bio-based nano-creations still qualify as robots, or are they simply complex drugs?
“There isn’t any established definition of a ‘nanorobot,'” said Douglas. “We asked robotics expert Rob Wood at Harvard about the term, and he said to describe what it does in general terms. We said that it senses friend or foe, and when a foe is sensed, it changes shape and attacks. He said this sounded similar to some military robots, and didn’t think the term was unjustified.”
Writers and futurists like Ray Kurzweil and Robert Freitas have suggested that, in the year 2030, nanorobots will carry more oxygen to our blood, repair cellular damage, rid our bodies of toxins, and help us reverse- engineer a human brain. Specifically, in his landmark book The Singularity Is Near: When Humans Transcend Biology (Viking, 2005), Kurzweil remarked that, in the 2020s, we could use complex nanomechanisms to “eliminate the accumulation of DNA transcription errors, one major source of the aging process. We could introduce DNA changes to essentially reprogram our genes. … We would also be able to defeat biological pathogens … by blocking any unwanted replication of genetic information.”
Douglas says he “would be very surprised” if the more bold predictions of Kurzweil and Freitas came to pass.
“We probably need a much better understanding of the basic science before we can achieve such sophisticated manipulations of our biology,” he said.
Douglas’s own aspirations for the future of the field are relatively restrained in comparison. He expressed cautious optimism that, within 20 years, “there will be at least one FDA-approved treatment that employs nanoscale devices that can perform actions approaching the sophistication of simple viruses (cell targeting, payload delivery, or reprogramming the cell). I think reprogramming and repurposing existing viruses also sounds like a promising approach.”
These nanorobots developed by Harvard researchers are programmed to carry antigens to cancer sites and release their payload when they come into contact with cancer tissue.
Sources: “A Logic-Gated Nanorobot for Targeted Transport of Molecular Payloads” by S. M. Douglas, I. Bachelet, and G. M. Church, Science (February 17, 2012).
Shawn Douglas (interview), Wyss Institute for Biologically Inspired Engineering at Harvard University, http://wyss.harvard.edu
Originally published in THE FUTURIST, May-June 2012