Invasion of the high-tech body snatchers

Ready for infrared vision, and hearts that work better than the original? While bioethicists obsess over cloning, bioengineers will soon be able to replace every part of our bodies.

Published September 30, 2003 7:30PM (EDT)

Right here, right now, it is virtually impossible to find a human being in the developed world who is not technologically enhanced or modified. Ever been vaccinated? Have a tooth crowned? Wear contact lenses? One does not need a pacemaker to qualify as a bioengineered Homo sapiens.

These examples have profound implications. There is no theoretical difference between a dental implant and a mental implant except that we know how a tooth works and can manufacture a functional replacement. Currently, the same cannot be said for the neural network of the brain. But from a bioengineering standpoint, that is only a matter of time.

Once the structure and function of an organ are elucidated, bioengineers can develop replacement parts. Artificial heart-valve implantation is practically routine. Next-generation pacemakers will come with built-in diagnostics and telemetry to provide your hospital's computer with a constant stream of data on the condition of both your heart and the pacemaker itself. Some designs even include global positioning systems for emergencies. Several tissue-engineering companies produce commercial synthetic-skin products for grafting onto burns. Some use a mixture of biological and synthetic polymers, while others offer the genuine article, natural tissue grown from cells. As these technologies emerge, humans will metamorphose: The first stage of our metamorphosis will, in fact, be the physical fusion of human beings with both the biological and nonbiological systems we are engineering.

But rather than the end, this quasi-cyborg, or "Homo technicus," is just the beginning. While bioethicists wring their hands about the morality of human cloning, and politicians battle about where we may or may not get our stem cells, nanotechnology is moving toward the elimination of the cell as the fundamental unit of life. Yet outside the laboratory, how many people are paying attention?

As a concept, bioengineering, like information technology, has entered our collective consciousness through the usual channels of the media. In practice, bioengineering enters our lives through advanced medical procedures and imaging technologies: the total hip replacement or the MRI.

Bioengineering, currently an embryonic technology, will grow to include genetic engineering but will use both living and nonliving materials for the devices it builds. Nanotechnology, the ability to design and assemble materials one atom at a time (aka "nanofabrication") is, by definition, the ultimate form of engineering for life-forms or devices operating in our physical world. Currently we are in the process of using these technologies to build the end of evolution.

The bioengineering mega-trend is crucial to the future of humanity because bioengineering via nanofabrication will erase the border between living and nonliving materials. Maybe not this century, but most likely in the next. The result will be the emergence of a totally new type of being. Homo sapiens is on a path toward speciation into Homo technicus. But Homo technicus will have no evolutionary relationship to biological life. Just the opposite. The ascendancy of Homo technicus will mark the end of that particular 4-billion-year experiment.

The current popular fixation on clones, or science fiction's obsession with cyborgs, does not provide useful paradigms for the new forms of sentience that will ultimately emerge from nanotechnology. Both clones and cyborgs are too anthropomorphic. Ultimately, the future will not be about mixing humanity and technology but about sentient chemistry. Just as the revolution in quantum physics laid the foundation for the creation of weapons capable of vaporizing the planet, so the nanotechnology revolution is laying the foundation for the end of evolution and of life in any form we can imagine.

Given this obvious outcome, one of the most amazing developments is what has failed to develop. There appears to be virtually no cohesive attempt to address the ethical challenges of bioengineering, challenges that are prima facie far beyond those posed by molecular biology. The scientific, and therefore ethical, boundaries of biotechnology are the cell and its biomolecular components. Bioengineering, on the other hand, knows no such limitations.

As the skein of technology continues to feed into the fabric of life, the yarn is undergoing molecular substitution. The natural fibers will be replaced as needed. The entire periodic table of elements is available and there is no reason for discrimination. Bioethicists are disastrously underestimating the trajectory of this technology. Issues of infinitely greater technical and ethical complexity than cloning are already on the table. Bioengineering is about to jump to warp speed while human psychology and consciousness plug along on impulse power. The slope may appear slippery now, but we are still human beings trying to keep our footing amid a tangle of DNA and stem cells.

That is about to change. But bioethicists seem unaware of the concept of sentient chemistry through nanotechnology. One possibility is that they do not have the technical training to properly evaluate the rate at which nanotechnology will supersede even the most advanced frontiers of biotechnology. Quantum leaps, so to speak, are in the cards. While no one doubts that we must deal with the unprecedented ethical and social implications of cloning, we must simultaneously create an expanded vocabulary that allows us to move beyond the biological and come to grips with a more realistic assessment of where our technology is taking us, and of who "us" will be. Terms such as "artificial intelligence" and "cloning" will soon be anachronisms. A vast technological entity has been created. It is almost already beyond comprehension. And we are just getting started.

This is not science fiction. This is happening in a laboratory near you.

Even with the limited tools available now, devices that function as part of the body are rapidly emerging. The vascular stent provides an excellent example with which to illustrate the present state and future prospects of bioengineering.

We all know arteries become clogged; debris accumulates on the inside of the blood vessel and flow is reduced. Untreated, the constriction can ultimately block the flow of blood to part of your body. If the blockage is in a coronary artery, a blood vessel that feeds the heart muscle itself, it is deadly.

The early bioengineering solution was to pry the constriction open with a procedure called a balloon angioplasty. The limitations of this approach are obvious. When you force something open, especially something with the limited flexibility of a hardened vessel wall, there are problems. Frequently, the vessel would relapse to its constricted state. So an improved engineering concept was developed. Open the constriction and simultaneously implant a structure to hold it open: the stent.

A coronary or vascular stent is a small slotted metal cylinder mounted on a balloon catheter, a long flexible tube capped by an expandable tip. When your pipe gets clogged, this catheter is inserted into your artery and snaked along until the balloon portion is at the site of the constriction. Then the balloon is inflated and deflated a number of times while, simultaneously, the metal stent expands and is pressed into the inner wall of the artery. The standard stent looks something like a tubular wire fence with flat, fat wires. It expands along with the balloon but then retains its larger diameter when the catheter is removed.

A stent is basically a plumbing device for the repair of a collapsed piece of pipe. It is also representative of the state of the art in applied bioengineering available on the market today. And, like computer displays and cellphones, stents have already undergone several product generations. Early stage enhancements were designed mainly to improve delivery and placement accuracy, or to eliminate potential catastrophes such as structural collapse or the formation of blood clots. A major bioengineering challenge has been to develop materials with sufficient tensile strength to hold the vessel open but malleable enough to be placed in the vessel with a minimum of damage to surrounding tissue.

Tissue damage as a result of stent placement calls for improved design specs. Not coincidentally, these new designs place us on the road to Homo technicus. Recently the FDA approved a "drug eluting" stent. This stent is metal with a plastic coating impregnated with a specific pharmaceutical. So it is a true hybrid: part device, part drug. The first compound incorporated into a drug-eluting stent was selected to reduce the regrowth of tissue into the region of the opened vessel, a process called restenosis. When wire is driven into the tissue of the vessel wall some cells are ruptured and others are mashed. The result is inflammation and wound healing. If too much tissue is produced, it re-clogs the vessel. From a bioengineering standpoint having the stent release a drug to inhibit restenosis is an excellent device modification.

Future drug-eluting stents will contain multiple active ingredients. The elution process will be refined so that the timing and amount of active ingredient that enters the tissue, the "elution profile," will be controlled with greater precision. Design specs will continue to be upgraded via the sequential timed release of a complex mixture of natural and synthetic chemicals to control the response of the wounded tissue. Further enhancement will involve attaching small protein molecules directly onto the stent surface to signal adjacent cells. Bioengineers call this molecular decoration.

Molecular decoration camouflages a nonbiological material in order to mimic a biological material. This type of strategy has been designated biomimetics. A protein-decorated, drug-eluting stent is one of the first true hybrid biomaterials: part biological, part synthetic. One small step for Homo technicus. Drug-eluting stents and their progeny will speak the language of the cell well enough to stimulate production of smooth endothelial cells on the inner surface of the stent, in effect growing a brand-new vessel surface. In later designs the stent itself will biodegrade after stimulating the growth of complete replacement vasculature. In this final design, we will have engineered tissue that will be in better shape than the rest of the vessel. In the process of therapeutic life-saving we will have generated a rejuvenated biosystem component.

This brings us to what I call the First Law of Biomimetics:

With respect to bioengineering there is no border between life-saving and life-enhancing technology.

The First Law of Biomimetics will drive Homo sapiens to the point of speciation. Practically speaking, bioengineers will adopt the tools of nanofabrication to fix our damaged parts and will then offer us enhanced parts. If we simply follow this road to its logical end we reach a point when the organism has so many modifications it just doesn't qualify as Homo sapiens anymore. A new species will emerge that differs both in psychology (software) and chemistry (hardware). The name Homo technicus does not imply any biological relationship but a fusion at the molecular and atomic level. For Homo technicus the difference between DNA and silicon will be no more significant than the difference between protein and DNA is to Homo sapiens. After all, our own bodies contain a wide range of structural materials, from the ceramic in bone to the organic polymer collagen in skin.

How will the First Law of Biomimetics drive Homo sapiens to speciation? The answer is that we will demand it. Many of the changes that technology offers are subject to interpretation, but few object to an increase in the quality and length of human life. When baby boomers say that their children can reasonably expect to live to be 85, we are talking about productive and active years, not the ways in which their deaths will be prolonged.

In our generation we expect, not hope, that biotechnology will bring an end to age-associated cognitive problems such as Alzheimer's and senile dementia. Within a generation or two we expect, not hope, that we will have hip and knee implants that function as well as or better than the worn-out originals. And, of course, we expect a cure for cancer. Or, more correctly, cures for cancers. Cancer is the ultimate "bad boy" of molecular biology because it comprises a multiplicity of diseases resulting from inappropriate gene expression -- the wrong permutation of the genetic code acting out at the wrong time in the wrong place. That is why a Normandy Beach frontal assault on cancer will not work. Like terrorist cells, cancer cells have multiple manifestos, multiple strategies, and an array of weapons at their disposal. Nevertheless we expect, not hope, that a complete understanding of the human genome and cellular function will enable us to deal with each particular cancer on its own terms.

Our increase in life expectancy is, of course, multivariate in nature; it is the result of enhanced medical care, improved nutrition (from advanced agricultural and food-manufacturing technologies), and the general techno-sheltering we receive from the wear and tear of direct interaction with the environment. But the greatest strides are expected to emerge from biotechnology and bioengineering. While bioethics per se thrives on slippery slopes shaded by the sinister foliage of death or dysfunctional biology, I am not aware of significant societal objection to medical advances that unambiguously enhance life. Say you need a heart transplant. Just to make the argument clean, we will assume the heart was grown in culture using your skin cells via tissue engineering. No embryonic stem cells need apply. Your surgeon comes in smiling and says, "Look, not only will this transplant save your life, but the new heart will also pump more efficiently and last longer than your original." Who among us would object?

We expect these advances and we will not be disappointed. Staying with the stent as our example, a dozen product generations down the road will see targeted stem cells injected into the bloodstream that will hunt down damaged vasculature, attach to the target site, and replace or repair the damage through tissue regeneration. This will be minimally invasive. "Minimally invasive" is what bioengineers want because that is what you and I want. Who among us would not prefer a virtual colonoscopy? But in the end our real desire is for a colon, lung or liver that has no possibility of developing diseases or disorders, and we will get it. The ultimate therapy is never having to need therapy. Bioengineers are looking for zero failure rates and this, in turn, means engineered tissues that are not limited to the design evolved by random variation followed by natural selection.

The term "biomimetics" is currently in vogue among bioengineers. I have written the why as its First Law. The how of biomimetics is how we design materials that go into the body. For now we strive to create biomaterials that mimic the original biological components. Such biomimetic materials have superior biocompatibility because the body does not recognize them as foreign. This desire for mimicry has its historic roots in the search for nonliving materials that can be implanted to achieve a desired medical outcome with a minimum of inflammation and immune rejection.

One story is that polymethyl methacrylate (PMMA) came into use as a biomaterial because, during World War II, flight surgeons noticed that, when this material was blown into bomber gunners, little or no inflammation ensued. But the days of PMMA ocular implants, stainless steel screws, and titanium rods are ending. The current frontier in biomaterials involves bioreactive biomimetic systems. The drug-eluting stent is just the beginning. We are looking for implanted materials that interact with the living components of the body to create cell growth, wound healing, or any number of other desirable therapeutic outcomes. But just "looking" won't cut it. Real biomimetics means knowledge-based nanofabrication of molecular composites built from whatever molecules serve the purpose best, be they proteins, DNA, silica or titanium.

As I stated at the outset, ultimately there will be no distinction between living and nonliving materials. The official beginning of the end of Homo sapiens will correspond to the completion of the lexicon of molecular cell biology, the point at which we gain the ability to speak the physiochemical dialect of the cell with fluency. This work goes on in thousands of laboratories every day. We may stand on the shoulders of giants, but we climbed up there on the backs of countless working scientists and engineers.

When I show my students a summary diagram of an essential metabolic pathway -- say, respiration or photosynthesis -- I remind them that behind that cartoon are literally tens of thousands of person-years of hard labor. Respiration is the metabolic pathway by which cellular energy is extracted via the molecular "burning," or oxidation, of sugar to water and carbon dioxide. Every morning for 20 years, this research started with dozens of technicians around the world going to slaughterhouses for fresh beef hearts, pig hearts, and similar energy-rich organs. These organs would be hauled back to the lab in ice buckets and ground up in giant kitchen blenders. To keep the enzymes from degrading, the technicians worked in walk-in coolers, bundled in jackets and gloves. One could conservatively estimate that a thousand person-years went into simply generating bovine heart-muscle milkshakes, usually by 9 a.m. Then the actual experiment of the day could begin.

Likewise, completion of the molecular cell biology lexicon will come as the culmination of billions of experiments that integrate and lay bare the complete blueprint of biology. This number may sound extreme, but robotic combinatorial microchemistry can knock off millions of reactions a day. Parallel efforts are occurring in fields such as materials science, chemical engineering and polymer chemistry. Driven by enormous market forces in medicine, information technology and defense, we are rapidly gaining an ability to manufacture devices with molecular and even atomic precision.

Once we fully understand cellular function at the molecular level, and can fabricate replacement parts from the entire palette of materials, why would "we" choose to remain simply carbon-based? When the lexicon is complete and fabrication tools are available, there will truly be no difference between a dental implant and a mental implant. Clearly the definition of a life-form will have to be modified as modes and even the need for reproduction or replication change or disappear. Homo technicus will emerge: the fusion of biology and high technology.

A future ancestor of Homo technicus may be seen in current efforts to grow electrochemical junctions between neurons and silicon semiconductors. In bioengineer-speak this would be called the nanofabrication of a bioelectrochemical-semiconductor hybrid sensor system. Periodically, news stories in the popular media remind us of this work. These reports are invariably upbeat, with science-fiction-like pictures of neuronal fingers snaking out to make contact with silicon wafers on a petri plate, often in surreal computer-enhanced color ... just like the Hubble telescope images of the stars. The optimistic take-home message is that bioengineers are working hard to develop artificial vision. Someday, we are told, a miniature silicon chip interfaced to the optic nerve will substitute for a nonfunctional retina. This chip will replace the damaged rods and cones of blind and visually impaired humans.

Rods and cones, after all, are just micro-machines (cells) made up of nano-components (biomolecules). These biomolecules transduce photons of light into electrical currents. These currents stimulate adjacent neurons in the optic nerve bundle. There is no reason why such electrical stimulation could not be provided by an appropriately fabricated light-transducing semiconductor material.

These updates in the popular press generally stay well below the bioethics radar. We are left with the distinct impression that this is a noble project, one that will naturally come to an end when sight is restored to the vision-impaired. But, in fact, the end is nowhere in sight. When we have this technology, why not use it to enhance our visual capabilities? What about infrared, ultraviolet and even X-ray vision? Will we voluntarily forgo an entire visual universe? And so it will go until Homo sapiens spawns Homo technicus.

Earlier, I suggested that bioethicists may not have the training to understand what is about to happen. This assessment will probably not endear me to the bioethics community, but it is useful to remember that biology is, or rather was, considered a "soft" science. Biology was what one studied if one aspired to a career in science but didn't want to take calculus and physics. Or, of course, if one wanted to go to medical school. The biology of the 21st century has many names, bioengineering, biotechnology and industrial biology among them, but the bottom line is that biology has become a "hard" science and is getting harder all the time. So hard, in fact, that it will soon have titanium components.

A recognition of the ethical implications of bioengineering should have followed logically from the ethical questions raised by genetic engineering. But somewhere in our human hearts we apparently need to believe that, even in a cyborg, there will be a border where biology starts and technology ends -- a plug, a slot, an interface. That, unfortunately, is a fantasy. Silicon and carbon are perfectly happy to bond on the molecular level. DNA has no mandate from any deity that gives it an eternal role as the information storage system of sentience. Homo technicus will be different at the atomic level. We are not only going through the looking glass; we are merging with it.

Homo technicus will, in turn, spawn Materio sapiens, a life-form that can only be understood on the basis of what it will not be. Materio sapiens will not be limited by the chemistry of carbon. Materio sapiens must come into being because the laws of physics and chemistry are all on its side. The chemistry of biological life is incredibly limited. After 4 billion years, biological systems have learned to use only a few dozen chemical reactions out of millions available just to the chemistry of carbon (aka organic chemistry). Approximately half the reactions carried out in your body proceed by the mere addition or removal of water or some minor variation involving water's component atoms, hydrogen and oxygen. When one begins to build "living" systems with other elements, the number of possible reactions and structures reach the trillions. Materio sapiens will emerge by the law of mass action. Carbon-based life will be inexorably diluted out by superior chemistry and physics.

Because it will be life by design rather than by random variation followed by natural selection, the emergence of Homo technicus will end Darwinian evolution. When the current driving force for natural selection is gone, when the 4-billion-year experiment is over, what will replace it? Technology-based life, really technology-based sentience, will divest itself of the two major characteristics of biology-based life. The first and most obvious defining quality of biological systems is the limited spectrum of chemical materials from which they are derived. A second, and perhaps more profound difference, is that engineering proceeds through design rather than by chance. Variability will become a tool rather than the rule.

The former concept is embodied in what I have called the First Law of Biomimetics. A reasonable formulation of the Second Law of Biomimetics might be: Nanofabrication will replace natural selection. Variability will exist only in forms such as combinatorial chemistry, where billions of compounds are synthesized randomly but then auditioned for a highly specific function.

Given this obvious trajectory, bioengineering should be right up on the radar screen with biological cloning. A bioethics debate with Homo technicus is not feasible, so bioethicists must engage long before the transition begins. Yet, except for the usual fearful warnings that "we" are turning into cyborgs, little sophisticated discussion of the ethical implications of bioengineering can be found. If we do not engage, the forces of technology will prevail by default. The crankshaft, so to speak, of the 4-billion-year engine that has driven evolution is about to snap. We will cut our tether to Darwinism and give way to uncharacterized beings moving through uncharted regions. For navigation in such regions the current bioethics debate provides no compass. Issues of human cloning won't mean much when humans are no longer the dominant species, or perhaps even extant.

With great Sturm und Drang, current futurists are busy shifting antiquated paradigms. If you are thinking like a human, you are not thinking far enough outside the box. In fact, if you think there is a box to think outside of, you have missed the point. Humans make boxes. And while the world of Homo technicus may still involve competition to extract limited resources from a hostile environment, it is almost impossible to envision an entity as advanced as Materio sapiens running low on battery power.

If we avoid projecting our evolutionary baggage onto Materio sapiens, we have irrevocably pulled the plug on our version of the meaning of life. In Darwin's world, the goal of all this random variation followed by natural selection was to improve our ability to compete. After competition, the successfully selected display the ultimate manifestation of evolutionary fitness, reproduction. We of Darwinian fitness see our genetic material take another step down the corridors of time. Homo technicus will inhabit a different domain. Random variation followed by natural selection will not be the name of the game, and the corridors will not be made of time. Inflicting our world on Homo technicus would be egregious egoism. More to the point, projecting our ethics would be futile.

Yet the contemporary bioethics debate appears incapable of the parallel processing necessary to address even the most rudimentary and obvious consequences of the nanotechnology revolution for humanity. While we argue endlessly about where cells may or may not come from, while we debate the morality of dispensing DNA with altered base sequences, sentient silicates are waiting just down the road. Medusa is preparing to turn us into stone ... or at least silicon, plastic and titanium. We have invited her in, so it is only polite, not to mention politic, to begin to discuss where she will sleep. Except she never sleeps and, of course, she is not a she.

Homo technicus is in the house and, while undoubtedly sentient, Homo technicus will be nothing like the anthropomorphic cyborg. With physical chemistry as the lingua franca, the frontiers and borders currently guarded by our bioethicists will fade away and, once gone, will not be remembered. Homo technicus will not be technically enhanced but fully integrated with the technology on a molecular/atomic level. Homo technicus won't be anything like us. Homo technicus won't see like us, breed like us, feed like us, or need like us. Homo technicus will have no more in common with Homo sapiens than Homo sapiens has with the bacterium Escherichia coli; in fact, much, much less. Homo technicus will evolve, if evolution is even the concept, into Materio sapiens. After that, all bets are off.

This story has been corrected since it was originally published.

By Alan H. Goldstein

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