Nanorobots injected to a cockroach have been successful in delivering a payload of drugs through an adaptive mechanism that could one day destroy cancer cells in humans.
Targeting cancer cells remain tricky for scientists who are using nanotechnology to come up with new drug delivery systems.
Similar receptors can be found in both cancer cells and healthy cells, and nanoparticles designed to attach to these receptors can produce unwanted side effects because they also destroy healthy cells.
Instead of targeting specific receptors, other researchers want nanoparticles to look for collections of cell features instead to be more selective.
Now, scientists have devised a way to refine that approach one step further by making what they call origami robots that react and unfold depending on the type of cell it encounters.
Unlike previous experiments wherein nanobots only respond to a predetermined cell type, these origami nanobots are more adaptable to a wide variety of cell types.
Researchers injected the nanobots into a cockroach where they roam around the insect's body, interact with cells and work with each other.
Upon encountering a diseased cell, the origami nanobots combine in a particular sequence that targets a specific protein then, as their namesake implies, unfolds to release a payload of drugs.
"DNA nanorobots could potentially carry out complex programs that could one day be used to diagnose or treat diseases with unprecedented sophistication,"
Says Daniel Levner, a bioengineer at the Wyss Institute at Harvard University, and co-author of the research study published in Nature Nanotechnology.
"Unlike electronic devices, which are suitable for our watches, our cars or phones, we can use these robots in life domains, like a living cockroach,"
Ángel Goñi Moreno of the National Center for Biotechnology in Madrid, Spain, told New Scientist.
"This opens the door for environmental or health applications."
Bioengineers like Levner are focusing on diseases like autoimmune disorders and cancer in applying nanotechnology.
A similar study by Harvard researchers also used DNA strands to target leukemia and lymphoma cells. Other scientists also hope that nanoparticles can target healthy native cells that attack the body's own immune system as what happens in autoimmune conditions like lupus and multiple sclerosis.
Scientists say DNA-based drug delivery systems can improve the traditional way of how doctors fight cancer.
Current treatments like radiation and chemotherapy can kill cancer cells but destroy healthy cells in the process as well. Using DNA nanobots can eliminate this problem by targeting cancer cells alone.
The Nanorobots Project
Levner's group took advantage of a DNA's double-helix structure that allows it to bind with other DNA to assume different shapes, like origami.
Levner and his colleagues were able to monitor the DNA nanobots inside the cockroach as they tag cells they encountered with fluorescent markers.
They then analyzed how the nanobots interacted with each other, how they delivered drugs and in which locations.
The researchers say the dynamic interaction between DNA molecules in their study can equal the computing power of 8-bit computers such as the Commodore 64 or Atari 800.
While the experiment was successful in simpler living animals like cockroaches, greater computing power will be needed as they try to use the nanobots in humans, during the first round of trials planned within five years.
Since the cellular system of humans is more complex, the number of nanorobots to be used will have to be increased, and their interactions multiplied, to come up with equally complex decisions and actions.
One challenge is how to overcome the body's natural immune response when it encounters foreign material like these nanobots.
But since DNA is biocompatible and biodegradable, scientists want to use this advantage and looking for ways to minimize an immune response against nanobots.