Visionaries 2020

The Future of Nanomedicine

By Robert A. Freitas Jr.

The founder of the Nanofactory Collaboration is innovating medicine molecule by molecule.

© 2009 Robert A. Freitas Jr.  All Rights Reserved.

 For countless centuries, physicians and their antecedents have sought to aid the human body in its efforts to heal and repair itself.  Slowly at first, and later with gathering speed, new methods and instruments have been added to the physician’s toolkit – anesthesia and x-ray imaging, antibiotics for jamming the molecular machinery of unwanted bacteria, microsurgical techniques for physically removing pathological tissue and reconfiguring healthy tissue, and most recently biotechnology, molecular medicine, pharmacogenetics and whole-genome sequencing, and early efforts at gene therapies.

In most cases, however, physicians must chiefly rely on the body’s ability to repair itself.  If this fails, external efforts may be useless.  We cannot today place the component parts of human cells exactly where they should be, and restructure them as they should be, to ensure a healthy physiological state.  There are no tools for working, precisely and with three-dimensional control, at the molecular level.

To obtain such tools, we need nanotechnology ( nanomedicine.com/NMI/1.1.htm ).  Nanotechnology is the engineering of atomically 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 five carbon atoms nestled side by side.  Nanomedicine is the application of nanotechnology to medicine.

The ultimate tool of nanomedicine is the medical nanorobot (nanomedicine.com/index.htm#NanorobotAnalyses ) – a robot the size of a bacterium, composed of many thousands of molecule-size mechanical parts perhaps resembling macroscale gears, bearings, and ratchets, possibly composed of a strong diamond-like material.  A nanorobot will need motors to make things move, and manipulator arms or mechanical legs for dexterity and mobility.  It will have a power supply for energy, sensors to guide its actions, and an onboard computer to control its behavior.  But unlike a regular robot, a nanorobot will be very small.  A nanorobot that would travel through the bloodstream must be smaller than the red cells in our blood – tiny enough to squeeze through even the narrowest capillaries in the human body.  Medical nanorobotics holds the greatest promise for curing disease and extending the human health span.  With diligent effort, the first fruits of this advanced nanomedicine could begin to appear in clinical treatment sometime during the 2020s.

For example, one medical nanorobot called a “microbivore” ( jetpress.org/volume14/freitas.pdf ) could act as an artificial mechanical white cell, seeking out and digesting unwanted pathogens including bacteria, viruses, or fungi in the bloodstream.  A patient with a bloodborne infection might be injected with a dose of about 100 billion microbivores (about 1 cc).  When a targeted bacterium bumps into a microbivore, the microbe sticks to the nanorobot’s surface like a fly caught on flypaper.  Telescoping grapples emerge from the microbivore’s hull and transport the pathogen toward the front of the device, bucket-brigade style, and into the microbivore’s “mouth.”  Once inside, the microbe is minced and digested into amino acids, mononucleotides, simple fatty acids and sugars in just minutes.  These basic molecules are then harmlessly discharged back into the bloodstream through an exhaust port at the rear of the device.  A complete treatment might take a few hours, far faster than the days or weeks often needed for antibiotics to work, and no microbe can evolve multidrug resistance to these machines as they can to antibiotics.  When the nanorobotic treatment is finished, the doctor broadcasts an ultrasound signal and the nanorobots exit the body through the kidneys, to be excreted with the urine in due course.  Related nanorobots could be programmed to quickly recognize and digest even the tiniest aggregates of early cancer cells.

Medical nanorobots could also be used to perform surgery on individual cells.  In one proposed procedure, a cell repair nanorobot called a “chromallocyte” ( jetpress.org/v16/freitas.pdf ), controlled by a physician, would extract all 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 outside of the patient’s body using a desktop nanofactory optimized for organic molecules.  The patient’s own individual genome serves as the blueprint to fabricate the new genetic material.  Each chromallocyte is loaded with a single copy of a 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.  If the patient chooses, inherited defective genes could be replaced with non-defective base-pair sequences, permanently curing any genetic disease and even permitting cancerous cells to be reprogrammed to a healthy state.  Perhaps most importantly, chromosome replacement therapy could correct the accumulating genetic damage and mutations that lead to aging in every one of our cells.

Right now, medical nanorobots are just theory.  To actually build them, we need to create a new technology called molecular manufacturing.  Molecular manufacturing is the production of complex atomically precise structures using positionally controlled fabrication and assembly of nanoparts inside a nanofactory, much like cars are manufactured on an assembly line.  The first experimental proof that individual atoms could be manipulated was obtained by IBM scientists back in 1989 when they used a scanning tunneling microscope to precisely position 35 xenon atoms on a nickel surface to spell out the corporate logo “IBM”.  Similarly, inside the nanofactory simple feedstock molecules such as methane (natural gas), propane, or acetylene will be manipulated by massively parallel arrays of tiny probe tips to build atomically precise structures needed for medical nanorobots.  In 2006, Ralph Merkle and I founded the Nanofactory Collaboration ( MolecularAssembler.com/Nanofactory ) to coordinate a combined experimental and theoretical R&D program to design and build the first working diamondoid nanofactory that could build medical nanorobots.

How are these ideas being received in the medical community?  Initial skepticism was anticipated, but over time people have begun taking the concept more seriously.  (In late 1999 when my first book on “nanomedicine” came out, googling the word returned only 420 hits but this number rose fourfold in 2000 and fourfold again in 2001, finally exceeding 1 million hits by 2008.)  Of course, most physicians cannot indulge themselves in exploring the future of medicine.  This is not only understandable but quite reasonable for those who must treat patients today with the methods available today.  The same is true of the medical researcher, diligently working to improve current pharmaceuticals, whose natural curiosity may be restrained by the knowledge that his or her success – no matter how dramatic – will eventually be superseded.  In both cases, what can be done today, or next year, is the most appropriate professional focus.

But only a fraction of today’s physicians and researchers need look ahead for the entire field of medicine to benefit.  Those practitioners who plan to continue their careers into the timeframe when nanomedical developments are expected to arrive – e.g., younger physicians and researchers, certainly those now in medical and graduate programs – can incrementally speed the development process, while simultaneously positioning their own work for best effect, if they have a solid idea of where the field of medicine is heading.  Those farther along in their careers will be better able to direct research resources today if the goals of nanomedicine are better understood.

The potential impact of medical nanorobotics is enormous.  Rather than using drugs that act statistically and have unwanted side effects, we can deploy therapeutic nanomachines that act with digital precision, have no side effects, and can report exactly what they did back to the physician.  Test results, ranging from simple blood panels to full genomic sequencing, should be available to the doctor within minutes of sample collection from the patient.  Continuous medical monitoring by embedded nanorobotic systems, as exemplified by the programmable dermal display ( nanogirl.com/museumfuture/freitastalk.htm ), can permit very early disease detection by patients or their physicians.  Such monitoring will also provide automatic collection of long-baseline physiologic data permitting detection of slowly developing chronic conditions that may take years or decades to develop, such as obesity, diabetes, calcium loss, or Alzheimer’s.

Drug companies?  Rather than brewing giant batches of single-action drug molecules, Big Pharma can shift to manufacturing large quantities of generic nanorobots of several basic types.  These devices could later be customized to each patient’s unique genome and physiology, then programmed to address specific disease conditions, on site in the doctor’s office at the time of need.  Could personal nanofactories ( rfreitas.com/Nano/NoninflationaryPN.pdf ) in patients’ homes eventually do some of this manufacturing?  Yes, especially if creative designs for new devices or procedures are placed online as open-source information.  But basic issues such as IP rights, quality control, legal liability, trustworthiness of design improvements and software upgrades, product branding, government regulation and the like should allow Big Pharma to retain a significant role in medical nanomachine manufacture even in an era of widespread at-home personal manufacturing.

Doctors and hospitals?  For commonplace pathologies such as cuts or bruises, colds or flu, bacterial infections or cancers of many kinds, individuals might keep a batch of generic nanorobots at the ready in their home medical appliance, ready to be reprogrammed at need either remotely by their doctor or by some generically-available procedure, allowing patients to self-treat in the simplest of cases.  Doctors in this situation will act in the role of consultants, advisors, or in some cases gatekeepers regarding a particular subset of regulated conventional treatments.  This will free up physicians and hospitals to deal with the most difficult or complex cases, including acute physical trauma and emergency care.  These practitioners can also concentrate on rare disease conditions;  many diseases also have few symptoms and thus go unrecognized for a long time.  Medical specialists will also be needed to plan and coordinate major body modifications such as cosmetic surgeries and genetic upgrades, as well as more comprehensive procedures such as whole-body rejuvenations that may involve cell repair of most of the tissue cells in the body and might require several days of continuous treatment in a specialized facility.

Cost containment?  Costs can be held down because molecular manufacturing can have intrinsically cheap production costs (probably on the order of $1/kg for a mature molecular manufacturing system) and can be a “green” technology generating essentially zero waste products or pollution during the manufacturing process.  Nanorobot life cycle costs can be very low because nanorobots, unlike drugs and other consumable pharmaceutical agents, are intended to be removed intact from the body after every use, then refurbished and recycled many times, possibly indefinitely.  Even if the delivery of nanomedicine doesn’t reduce total health-care expenditures – which it should – it will likely free up billions of dollars that are now spent on premiums for private and public health-insurance programs.

Many are working to extend the bounds of conventional medicine, so here it is relatively difficult for one person to make a big difference.  Few are given the opportunity (the perspective, the resources, and the willingness) to look a bit farther down the road, identifying an exciting long-term vision for medical technology and then planning the detailed steps necessary to achieve it.  Planning and executing these steps toward the long-term vision has been my career and my passion for the last two decades.  As the technologies I’m working on come more clearly into focus, more people will acknowledge them as realistic and their enhanced trust in the longer-term vision will help speed the development of medical nanorobotics.

 

About the Author

Robert A. Freitas Jr. is senior research fellow at the Institute for Molecular Manufacturing (IMM) in California, after serving as a research scientist at Zyvex Corp. in Texas during 2000-2004. He is the author of Nanomedicine (Landes Bioscience, 1999, 2003), the first technical book series on medical nanorobotics. Web site www.rfreitas.com. Freitas is the 2009 winner of the Feynman Prize in nanotechnology for theory.