Sunday, December 26, 2010


Industrial manufacturing has, for the past two hundred years, mostly been concerned with macro-scale objects. The specifications for our cars, bridges, homes, and widgets are almost always in familiar dimensions that we can see or feel. Partially this is out of necessity: until recently, we simply lacked the ability for more precise specifications. Millimeters are the smallest units of length we deal with in our everyday lives, so making our products accurate to this level was typically good enough. This is quickly changing.

Nanotechnology is the science of manipulating objects on nanometer (one-billionth of a meter) scales. At this level, it is possible to position individual atoms and molecules where we want them. One of the best-known early demonstrations of this concept came in 1989, when IBM scientists essentially used molecule-sized tongs to carefully pick up and position 35 xenon atoms to spell IBM. Since then, our ability to work with tiny objects has improved every year, and shows no sign of slowing down. One of the most useful applications to date is in computing: Nearly all modern computer chips now use transistors that are only a few nanometers across.

Other applications of nanotechnology are starting to reach the market. Stain-proof and water-proof clothes have been available for a few years now. The cotton fibers in the clothes are attached to tiny nanomachines which actively repel foreign substances like water. Nanoparticles have found their way into commercial sunscreens as well, making them much more effective by forming a thin screen at the molecular level.

But today’s applications are just the tip of the iceberg of nanotechnology’s potential. As our ability to manipulate tiny structures improves, so will the range of possibilities available to us. Mature nanotechnology will grant us access to a veritable cornucopia of goods. Graphene – an arrangement of carbon atoms first created in 2004 – is 100 times stronger than steel, harder than diamond, but as flexible as plastic. It is one of the thinnest, lightest, strongest substances ever discovered, and may find its way into many common products in the coming decades, making computers faster, batteries better, food fresher, solar cells more efficient, and vehicles and bridges lighter. Two scientists took home the 2010 Nobel Physics Prize for their work with graphene.

Another recently-discovered nanoparticle, the gold nanosphere, may one day prove to be an effective cancer treatment. Its talent lies in its tiny size and its ability to conduct immense amounts of heat. By attaching a piece of protein to a gold nanosphere, it is capable of seeking out cancer cells and attaching itself. Once it has attached itself, a doctor can flash a burst of infrared light. This causes the gold nanosphere to heat up to extreme temperatures, killing the cell to which it is attached. If it withstands FDA trials, it could become a standard treatment for cancer, since it results in far less collateral damage than chemotherapy.

But new substances and chemicals are not the only benefit of nanotechnology. In the more distant future, there is no physical barrier preventing the development of microscopic robots at the nano-scale. These nanobots could radically transform our world – patrolling the environment to clean up pollution one molecule at a time, keeping intruding pathogens or harmful mutations out of our bodies, assembling anything we want from a hamburger to a piece of jewelry in front of our eyes, or (if proper precautions aren’t taken) consuming the entire world and reducing it to gray goo. In 1995, the late nanotechnology grandfather Richard Smalley wrote, “The list of things you could do with nanotechnology reads like much of the Christmas Wish List of our civilization.” As we master the ability to manipulate the world at the atomic level, we must also master the ability to prevent the technology from destroying us.

By 2026 – At least one treatment employing nanoparticles is routinely used in the United States to treat cancer.
By 2035 – Graphene is routinely used in structures (e.g. bridges and buildings) that need to be strong and light.
By 2050 – Nanobots can patrol the cells of our bodies, looking for any unwelcome intruders or mutations.
By 2055 – Molecular assemblers are able to produce nearly any macro-scale product we need, provided that they have the raw materials.

Saturday, December 11, 2010

The Future of Health Care: Regenerative Medicine and Stem Cells

When an octopus is injured and loses one of its limbs, it will grow back after several months. When a starfish loses an appendage, not only will the starfish grow a new arm, but the severed arm will grow a new starfish! Even among vertebrates, regeneration is not unknown – salamanders can regrow lost body parts. Yet when a human loses an appendage, it is forever lost. What do these animals do that we don’t? Many scientists believe that the capacity for regeneration is lying dormant within our biology, and we may soon be able to activate it.

Most complex organisms including humans contain a huge number of different types of cells that each perform a specific function within the body. For the most part, these cells cannot do anything else; a brain cell can never become a white blood cell, or vice versa. But in addition to these specialized types of cells, we have stem cells – “wild card” cells that have no specific function of their own, but are able to become whatever type of cell the body needs. Stem cells show great promise in treating a wide range of diseases, rejuvenating our organs and tissues, and replacing entire body parts.

For several decades, the organ transplant process has been horrendously inefficient. The standard procedure has been for patients to beg their friends and family to donate an organ…if they can even find a compatible donor. If not, they enter their name onto a hopelessly long organ wait list, where they may die before finding a suitable replacement. If they are lucky enough to receive a transplant, patients will spend the rest of their lives taking a strict regimen of drugs to prevent their body from “rejecting” the organ (i.e. viewing it as a hostile invader to be eliminated).

Regenerative medicine will soon transform this process. People will be able to grow their own replacement organs in a lab, and since the new organ is their own, there will be no worries about their body rejecting it. Substantial progress has already been made in many areas. In 2006, doctors first created a human bladder from scratch. They extracted a few bladder cells from patients, and pasted them onto a three-dimensional mold shaped like a bladder. To their delight, the cells quickly grew into a new, fully-functional bladder, which they then transplanted into the patient. In 2010, doctors first performed a similar procedure using stem cells instead of bladder cells. Regenerative medicine is quickly becoming the standard for treating serious bladder diseases. Clinical trials are underway for similar procedures for other organs including the heart, although these procedures are at least a decade from being used in hospitals. In June 2010, scientists successfully grew a liver in the laboratory for the first time.

But replacing entire organs is not the only promising use for regenerative medicine. There is no fundamental reason why tissues and organs that have been badly damaged – by disease, injury, or natural wear and tear – cannot gradually be rejuvenated by replacing the damaged cells with healthy stem cells, allowing our body parts to remain in excellent condition throughout our lives. This has ramifications for slowing the human aging process, and possibly even reversing it. When people are able to replace their organs with newer versions of themselves, “old age” will need not be regarded as a time of enfeeblement and illness.

Our stem cells are essentially a blank slate, which can become whatever type of cell we want them to become. Their potential applications to regenerative medicine are practically limitless, as practically every major non-infectious, non-genetic disease results in some form of cellular damage. Regenerative medicine treatment will be a relatively slow and non-disruptive transformation – we will gradually see more and more of these therapies over the next few decades – and is not a cure-all by any means. However, it is one of the most promising new treatments (along with genomics) which will eventually radically extend the human lifespan.

Saturday, December 4, 2010

Arsenic-Based Life

This week, NASA geobiologist Felisa Wolfe-Simon announced the discovery of arsenic-based microbes in Mono Lake in Yosemite National Park. This is a major scientific bombshell that is causing biologists to re-examine much of the conventional wisdom about what life is. All life, from the smallest bacteria to the largest redwood tree, was thought to be based on five elements: Carbon, hydrogen, oxygen, nitrogen, and phosphorus. These elements are crucial ingredients in life’s software – DNA and RNA molecules – as well as life’s fuel – ATP molecules. But now scientists have discovered organisms that use arsenic instead of phosphorus in their biochemistry, which was thought to be impossible. Most organisms are poisoned by arsenic because it is highly reactive, destroying the DNA and ATP found in living cells. But this new species of extremophile not only thrives in a lake with an arsenic concentration 700 times what the EPA deems safe, but actually manages to incorporate it into its DNA and ATP. This is more than just a strange new species with an interesting quirk; many of those are discovered every year. This is a radical redefinition of what “life” is.

Although these microbes appear to have evolved from more traditional forms of life, their mere existence opens up the possibility of a "shadow biosphere" on earth. All known living things have descended from a common ancestor, but what if organisms with other biochemistries are living right under our noses undetected? Might they provide evidence of a second genesis on earth? If life has developed twice, with two different biochemistries, it would prove that the evolution of life on earth was not just a one-in-a-trillion fluke, and would greatly increase the likelihood of life developing on any suitable world.

The discovery of arsenic-based life has important applications in the search for extraterrestrial life, which is where NASA comes in. For ages, scientists have pondered about the possibility of completely new types of life. A handful of astrobiologists (and a slew of science fiction writers) have speculated that extraterrestrial life might be too alien for us to even recognize as life. In fact, this is one possible explanation for Fermi's Paradox, which questions why we haven't already found life if it is commonplace in the universe. In light of this week's discovery, this explanation has become a lot more plausible. Perhaps DNA, reliance on water, and cells are just unique traits of life on earth, and we are barking up the wrong tree if we focus solely on finding them elsewhere.

Others have believed that “life as we know it” was the only type of life possible. This has been the dominant mindset of NASA for several decades, and is the basis of NASA’s search for life. NASA has concentrated its efforts on locating worlds similar to our own, where the conditions exist to permit the development of life as we know it. This generally means finding worlds with water on them, located in the “Goldilocks Zone” of their solar systems where they are neither too hot nor too cold to sustain life. This, of course, has been premised on the assumption that any extraterrestrial life is probably not too different from the life we know.

The discovery of arsenic-based life has cast doubt on this approach. If a new form of life can be found in Yosemite National Park, we can scarcely imagine how different extraterrestrial life must be. NASA’s obsessive search for earth-like planets may be overlooking a huge number of worlds where life may exist, in forms unknown to us earthlings. If it is possible for life to exist with a completely different biochemistry from our own, then it’s equally possible that it could thrive on worlds far different from our own, under conditions that have traditionally been regarded as hostile to life.

NASA will need to do a lot of soul-searching in light of this week’s discovery, and reevaluate how it determines if a world is potentially suitable for life. For the first time in history, a long-standing astrobiological question has been answered: Is “life as we know it” the only type of life possible? We now have our answer: It is not.