Nanorobots in Your Future

An exciting revolution in health care and medical technology looms large on the horizon. Yet the agent of change is microscopically small, and will be made possible by nanotechnology. Nanotechnology is the engineering of molecularly precise structures and, ultimately, molecular machines. The prefix “nano-“ refers to the scale of these constructions. A nanometer is one-billionth of a meter, the width of about 5 carbon atoms nestled side by side. Nanomedicine is the application of nanotechnology to medicine. The ultimate tool of nanomedicine is the medical nanorobot – a robot the size of a bacterium, composed of molecule-size parts somewhat resembling macroscale gears, bearings, and ratchets.

The first and most famous scientist to voice the possibility of nanorobots traveling through the body, searching out and clearing up diseases, was the late Nobel physicist Richard P. Feynman. In his remarkably prescient 1959 talk “There’s Plenty of Room at the Bottom,” Feynman proposed employing machine tools to make smaller machine tools, these to be used in turn to make still smaller machine tools, and so on all the way down to the atomic level, noting that this is “a development which I think cannot be avoided.”

With these small machine tools in hand, small mechanical devices, including nanorobots, could be constructed. This technology, said Feynman, “suggests a very interesting possibility for relatively small machines. Although it is a very wild idea, it would be interesting in surgery if you could swallow the surgeon. You put the mechanical surgeon inside the blood vessel and it goes into the heart and looks around. (Of course the information has to be fed out.) It finds out which valve is the faulty one and takes a little knife and slices it out. …[Imagine] that we can manufacture an object that maneuvers at that level!… Other small machines might be permanently incorporated in the body to assist some inadequately functioning organ.”

We cannot build such tiny robots today. But perhaps by the late 2020s or early 2030s, we will. These future devices may be made of rigid diamondoid nanometer-scale parts and subsystems including onboard sensors, motors, manipulators, and molecular computers. They will be fabricated in a nanofactory via positional assembly: picking and placing molecular parts one by one, then moving them along controlled trajectories much like the robot arms that manufacture cars on automobile assembly lines. These steps are repeated over and over with all the different parts until the final product, such as a medical nanorobot, is fully assembled.

The ability to build nanorobots cheaply and in therapeutically useful numbers would revolutionize the practice of medicine. Performance improvements up to 1000-fold over natural biological systems of similar function appear possible. For example, the respirocyte is an artificial mechanical red blood cell just 1 micron in diameter having 1/100th the volume of a natural red cell. Red cells carry oxygen to our tissues and remove carbon dioxide. Respirocytes do too, but would be made of much stronger diamond-like materials, not floppy lipids and proteins as we find in living cells. This allows respiratory gases to be safely stored within the respirocyte at tremendous pressures – up to 1000 atmospheres – and to be loaded or unloaded, molecule by molecule, using mechanical pumps on the device’s surface. This simple nanorobot is regulated by onboard computers, powered by glucose fuel cells, and controlled by a physician who communicates with the device via ultrasound signals beamed into the body from outside. A therapeutic 5-cc injection of respirocytes, just 1/1000th of total blood volume, duplicates the oxygen-carrying ability of the entire human blood mass and could instantly revive emergency victims of carbon monoxide poisoning at the scene of a fire.

Artificial mechanical white blood cells called microbivores are nanorobots that would seek and digest harmful bloodborne pathogens including bacteria, viruses, or fungi. The pathogens are completely digested into harmless sugars, amino acids and the like, which are the only effluents from this 3-micron nanorobot. No matter that a bacterium has acquired multiple drug resistance to antibiotics or to any other traditional treatment – the microbivore will eat it anyway. Microbivores would completely clear even the most severe bloodborne infections in hours or less, then be removed from the body. This is 1000 times faster than the weeks or months often needed for antibiotic-based cures. Related medical nanorobots with enhanced tissue mobility could similarly consume tumor cells with unmatched speed and surgical precision, eliminating cancer. Other devices could be programmed to remove circulatory obstructions in just minutes, quickly rescuing even the most compromised stroke victim from near-certain brain damage.

Nanorobots could perform surgery on individual cells. In one procedure, a nanorobot called a chromallocyte, controlled by a physician, would extract existing chromosomes from a diseased cell and insert fresh new ones in their place. This process is called chromosome replacement therapy. The replacement chromosomes are manufactured earlier, outside of the patient’s body, by a desktop nanofactory that includes a molecular assembly line, using the patient’s individual genome as the blueprint. If the patient chooses, inherited defective genes could be replaced with nondefective base-pair sequences, permanently curing any genetic disease and permitting cancerous cells to be reprogrammed to a healthy state. Each chromallocyte is loaded with a single copy of the digitally-corrected chromosome set. After injection, each device travels to its target tissue cell, enters the nucleus, replaces old worn-out genes with new chromosome copies, then exits the cell and is removed from the body.

The implications for extension of healthy lifespan are profound. Perhaps most importantly, chromosome replacement therapy could be used to correct the accumulating genetic damage and mutations that leads to aging in every one of your cells. With annual checkups and cleanouts, and some occasional major cellular repairs, your biological age could be restored once a year to a more or less constant physiological age that you select. Nanomedicine thus may permit us first to arrest, and later to reverse, the biological effects of aging and most of the current medical causes of natural death, severing forever the link between calendar time and biological health.