The Singularity Is Near: When Humans Transcend Biology (55 page)

For example, nanoengineered blood-borne devices that deliver hormones such as insulin have been demonstrated in animals.
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Similar systems could precisely deliver dopamine to the brain for Parkinson’s patients, provide bloodclotting factors for patients with hemophilia, and deliver cancer drugs directly to tumor sites. One new design provides up to twenty substance-containing reservoirs that can release their cargo at programmed times and locations in the body.
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Kensall Wise, a professor of electrical engineering at the University of Michigan, has developed a tiny neural probe that can provide precise monitoring of the electrical activity of patients with neural diseases.
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Future designs are also expected to deliver drugs to precise locations in the brain. Kazushi Ishiyama at Tohoku University in Japan has developed micromachines that use microscopic spinning screws to deliver drugs to small cancer tumors.
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A particularly innovative micromachine developed by Sandia National Laboratories has microteeth with a jaw that opens and closes to trap individual cells and then implant them with substances such as DNA, proteins, or drugs.
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Many approaches are being developed for micro- and nanoscale machines to go into the body and bloodstream.

Ultimately we will be able to determine the precise nutrients (including all the hundreds of phytochemicals) necessary for the optimal health of each individual. These will be freely and inexpensively available, so we won’t need to bother with extracting nutrients from food at all.

Nutrients will be introduced directly into the bloodstream by special metabolic nanobots, while sensors in our bloodstream and body, using wireless communication, will provide dynamic information on the nutrients needed at each point in time. This technology should be reasonably mature by the late 2020s.

A key question in designing such systems will be, How will nanobots be introduced into and removed from the body? The technologies we have today, such as intravenous catheters, leave much to be desired. Unlike drugs and nutritional supplements, however, nanobots have a measure of intelligence and can keep track of their own inventories and intelligently slip in and out of our bodies in clever ways. One scenario is that we would wear a special nutrient device in a belt or undershirt, which would be loaded with nutrient-bearing nanobots that could enter the body through the skin or other body cavities.

At that stage of technological development, we will be able to eat whatever we want, whatever gives us pleasure and gastronomic fulfillment, exploring the culinary arts for their tastes, textures, and aromas while having an optimal flow of nutrients to our bloodstream. One possibility to achieve this would be to have all the food we eat pass through a modified digestive tract that doesn’t allow absorption into the bloodstream. But this would place a burden on our colon and bowel functions, so a more refined approach would be to dispense with the conventional function of elimination. We could accomplish that by using special elimination nanobots that act like tiny garbage compactors. As the nutrient nanobots make their way into our bodies, the elimination nanobots go the other way. Such an innovation would also enable us to outgrow
grow the need for the organs that filter the blood for impurities, such as the kidneys.

Ultimately we won’t need to bother with special garments or explicit nutritional resources. Just as computation will be ubiquitous, the basic metabolic nanobot resources we need will be embedded throughout our environment. But it will also be important to maintain ample reserves of all needed resources
inside
the body. Our version 1.0 bodies do this to only a very limited extent—for example, storing a few minutes’ worth of oxygen in our blood and a few days’ worth of caloric energy in glycogen and other reserves. Version 2.0 will provide substantially greater reserves, enabling us to be separated from metabolic resources for greatly extended periods of time.

Of course, most of us won’t do away with our old-fashioned digestive process when these technologies are first introduced. After all, people didn’t throw away their typewriters when the first generation of word processors was introduced. However, these new technologies will in due course dominate. Few people today still use a typewriter, a horse and buggy, a wood-burning stove, or other displaced technologies (other than as deliberate experiences in antiquity). The same phenomenon will happen with our reengineered bodies. Once we’ve worked out the inevitable complications that will arise with a radically reengineered gastrointestinal system, we’ll begin to rely on it more and more. A nanobot-based digestive system can be introduced gradually, first augmenting our digestive tract, replacing it only after many iterations.

Programmable Blood.
One pervasive system that has already been the subject of a comprehensive conceptual redesign based on reverse engineering is our blood. I mentioned earlier Rob Freitas’s nanotechnology-based designs to replace our red blood cells, platelets, and white blood cells.
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Like most of our biological systems our red blood cells perform their oxygenating function very inefficiently, so Freitas has redesigned them for optimal performance. Because his respirocytes (robotic red blood cells) would enable one to go hours without oxygen,
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it will be interesting to see how this development is dealt with in athletic contests. Presumably the use of respirocytes and similar systems will be prohibited in events like the Olympics, but then we will face the prospect of teenagers (whose bloodstreams will likely contain respirocyte-enriched blood) routinely outperforming Olympic athletes. Although prototypes are still one to two decades in the future, their physical and chemical requirements have been worked out in impressive detail. Analyses show that Freitas’s designs would be hundreds or thousands of times more capable of storing and transporting oxygen than our biological blood.

Freitas also envisions micron-size artificial platelets that could achieve homeostasis (bleeding control) up to one thousand times faster than biological platelets do,
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as well as nanorobotic “microbivores” (white-blood-cell replacements) that will download software to destroy specific infections hundreds of times faster than antibiotics and will be effective against all bacterial, viral, and fungal infections, as well as cancer, with no limitations of drug resistance.
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Have a Heart, or Not.
The next organ on our list for enhancement is the heart, which, while an intricate and impressive machine, has a number of severe problems. It is subject to a myriad of failure modes and represents a fundamental weakness in our potential longevity. The heart usually breaks down long before the rest of the body, often very prematurely.

Although artificial hearts are beginning to be feasible replacements, a more effective approach will be to get rid of the heart altogether. Among Freitas’s designs are nanorobotic blood cells that provide their own mobility. If the blood moves autonomously, the engineering issues of the extreme pressures required for centralized pumping can be eliminated. As we perfect ways to transfer nanobots to and from the blood supply, we will eventually be able to continuously replace them. Freitas has also published a design for a complex five-hundred-trillion-nanorobot system, called a “vasculoid,” that replaces the entire human bloodstream with nonfluid-based delivery of essential nutrients and cells.
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Energy for the body will also be provided by microscopic fuel cells, using either hydrogen or the body’s own fuel, ATP. As I described in the last chapter, substantial progress has been made recently with both MEMS-scale and nanoscale fuel cells, including some that use the body’s own glucose and ATP energy sources.
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With the respirocytes providing greatly improved oxygenation, we will be able to eliminate the lungs by using nanobots to provide oxygen and remove carbon dioxide. As with other systems, we will go through intermediate stages where these technologies simply augment our natural processes, so we can have the best of both worlds. Eventually, though, there will be no reason to continue with the complications of actual breathing and the burdensome requirement of breathable air everywhere we go. If we find breathing itself pleasurable, we can develop virtual ways of having this sensual experience.

In time we also won’t need the various organs that produce chemicals, hormones, and enzymes that flow into the blood and other metabolic pathways. We can now synthesize bio-identical versions of many of these substances, and within one to two decades we will be able to routinely create the vast majority
of biochemically relevant substances. We are already creating artificial hormone organs. For example, the Lawrence Livermore National Laboratory and California-based Medtronic MiniMed are developing an artificial pancreas to be implanted under the skin. It will monitor blood glucose levels and release precise amounts of insulin, using a computer program to function like our biological pancreatic islet cells.
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In human body version 2.0 hormones and related substances (to the extent that we still need them) will be delivered via nanobots, controlled by intelligent biofeedback systems to maintain and balance required levels. Since we will be eliminating most of our biological organs, many of these substances may no longer be needed and will be replaced by other resources required by the nanorobotic systems.

So What’s Left?
Let’s consider where we are, circa early 2030s. We’ve eliminated the heart, lungs, red and white blood cells, platelets, pancreas, thyroid and all the hormone-producing organs, kidneys, bladder, liver, lower esophagus, stomach, small intestines, large intestines, and bowel. What we have left at this point is the skeleton, skin, sex organs, sensory organs, mouth and upper esophagus, and brain.

The skeleton is a stable structure, and we already have a reasonable understanding of how it works. We can now replace parts of it (for example, artificial hips and joints), although the procedure requires painful surgery, and our current technology for doing so has serious limitations. Interlinking nanobots will one day provide the ability to augment and ultimately replace the skeleton through a gradual and noninvasive process. The human skeleton version 2.0 will be very strong, stable, and self-repairing.

We will not notice the absence of many of our organs, such as the liver and pancreas, since we do not directly experience their operation. But the skin, which includes our primary and secondary sex organs, may prove to be an organ we will actually want to keep, or we may at least want to maintain its vital functions of communication and pleasure. However, we will ultimately be able to improve on the skin with new nanoengineered supple materials that will provide greater protection from physical and thermal environmental effects while enhancing our capacity for intimate communication. The same observation holds for the mouth and upper esophagus, which constitute the remaining aspects of the digestive system that we use to experience the act of eating.

Redesigning the Human Brain.
As we discussed earlier, the process of reverse engineering and redesign will also encompass the most important system in
our bodies: the brain. We already have implants based on “neuromorphic” modeling (reverse engineering of the human brain and nervous system) for a rapidly growing list of brain regions.
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Researchers at MIT and Harvard are developing neural implants to replace damaged retinas.
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Implants are available for Parkinson’s patients that communicate directly with the ventral posterior nucleus and subthalmic nucleus regions of the brain to reverse the most devastating symptoms of this disease.
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An implant for people with cerebral palsy and multiple sclerosis communicates with the ventral lateral thalamus and has been effective in controlling tremors.
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“Rather than treat the brain like soup, adding chemicals that enhance or suppress certain neurotransmitters,” says Rick Trosch, an American physician helping to pioneer these therapies, “we’re now treating it like circuitry.”

A variety of techniques is also being developed to provide the communications bridge between the wet analog world of biological information processing and digital electronics. Researchers at Germany’s Max Planck Institute have developed noninvasive devices that can communicate with neurons in both directions.
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They demonstrated their “neuron transistor” by controlling the movements of a living leech from a personal computer. Similar technology has been used to reconnect leech neurons and coax them to perform simple logical and arithmetic problems.

Scientists are also experimenting with “quantum dots,” tiny chips comprising crystals of photoconductive (reactive to light) semiconductor material that can be coated with peptides that bind to specific locations on neuron cell surfaces. These could allow researchers to use precise wavelengths of light to remotely activate specific neurons (for drug delivery, for example), replacing invasive external electrodes.
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Such developments also provide the promise of reconnecting broken neural pathways for people with nerve damage and spinal-cord injuries. It had long been thought that re-creating these pathways would be feasible only for recently injured patients, because nerves gradually deteriorate when unused. A recent discovery, however, shows the feasibility of a neuroprosthetic system for patients with long-standing spinal-cord injuries. Researchers at the University of Utah asked a group of long-term quadriplegic patients to move their limbs in a variety of ways and then observed the response of their brains, using magnetic resonance imaging (MRI). Although the neural pathways to their limbs had been inactive for many years, the patterns of their brain activity when attempting to move their limbs was very close to those observed in nondisabled persons.
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