The Singularity Is Near: When Humans Transcend Biology (45 page)

Nonetheless, hundreds of projects have begun applying nanotechnology to enhancing industrial processes and explicitly address existing forms of pollution. A few examples:

• There
  is extensive investigation of the use of nanoparticles for treating, deactivating, and removing a wide variety of environmental toxins. The nanoparticle forms of oxidants, reductants, and other active materials have shown the ability to transform a wide range of undesirable substances. Nanoparticles activated by light (for example, forms of titanium dioxide and zinc oxide) are able to bind and remove organic toxins and have low toxicity themselves.
  ¹⁴²
  In particular, zinc oxide nanoparticles provide a particularly powerful catalyst for detoxifying chlorinated phenols. These nanoparticles act as both sensors and catalysts and can be designed to transform only targeted contaminants.
  
• Nanofiltration membranes for water purification provide dramatically improved removal of fine-particle contaminants, compared to conventional methods of using sedimentation basins and wastewater clarifiers. Nanoparticles with designed catalysis are capable of absorbing and removing impurities. By using magnetic separation, these nanomaterials can be reused, which prevents them from becoming contaminants themselves. As one of many examples, consider nanoscale aluminosilicate molecular sieves called zeolites, which are being developed for controlled oxidation of hydrocarbons (for example, converting toluene to nontoxic benzaldehyde).
  ¹⁴³
  This method requires less energy and reduces the volume of inefficient photoreactions and waste products.
  
• Extensive research is under way to develop nanoproduced crystalline materials for catalysts and catalyst supports in the chemical industry. These catalysts have the potential to improve chemical yields, reduce toxic by-products, and remove contaminants.
  ¹⁴⁴
  For example, the material MCM-41 is now used by the oil industry to remove ultrafine contaminants that other pollution-reduction methods miss.
  
• It’s estimated that the widespread use of nanocomposites for structural material in automobiles would reduce gasoline consumption by 1.5 billion liters per year, which in turn would reduce carbon dioxide emissions by five billion kilograms per year, among other environmental benefits.
  
• Nanorobotics can be used to assist with nuclear-waste management. Nanofilters can separate isotopes when processing nuclear fuel. Nanofluids can improve the effectiveness of cooling nuclear reactors.
  
• Applying nanotechnology to home and industrial lighting could reduce both the need for electricity and an estimated two hundred million tons of carbon emissions per year.
  ¹⁴⁵
  
• Self-assembling electronic devices (for example, self-organizing biopolymers), if perfected, will require less energy to manufacture and use and
  will produce fewer toxic by-products than conventional semiconductormanufacturing methods.
  
• New computer displays using nanotube-based field-emission displays (FEDs) will provide superior display specifications while eliminating the heavy metals and other toxic materials used in conventional displays.
  
• Bimetallic nanoparticles (such as iron/palladium or iron/silver) can serve as effective reductants and catalysts for PCBs, pesticides, and halogenated organic solvents.
  ¹⁴⁶
  
• Nanotubes appear to be effective absorbents for dioxins and have performed significantly better at this than traditional activated carbon.
  ¹⁴⁷
  

This is a small sample of contemporary research on nanotechnology applications with potentially beneficial impact on the environment. Once we can go beyond simple nanoparticles and nanolayers and create more complex systems through precisely controlled molecular nanoassembly, we will be in a position to create massive numbers of tiny intelligent devices capable of carrying out relatively complex tasks. Cleaning up the environment will certainly be one of those missions.

Nanobots in the Bloodstream

Nanotechnology has given us the tools … to play with the ultimate toy box of nature—atoms and molecules. Everything is made from it…. The possibilities to create new things appear limitless.

                   —N
OBELIST
H
ORST
S
TÖRMER

The net effect of these nanomedical interventions will be the continuing arrest of all biological aging, along with the reduction of current biological age to whatever new biological age is deemed desirable by the patient, severing forever the link between calendar time and biological health. Such interventions may become commonplace several decades from today. Using annual checkups and cleanouts, and some occasional major repairs, your biological age could be restored once a year to the more or less constant physiological age that you select. You might still eventually die of accidental causes, but you’ll live at least ten times longer than you do now.

                   —R
OBERT
A. F
REITAS
J
R
.
¹⁴⁸

A prime example of the application of precise molecular control in manufacturing will be the deployment of billions or trillions of nanobots: small robots the size of human blood cells or smaller that can travel inside the bloodstream.
This notion is not as futuristic as it may sound; successful animal experiments have been conducted using this concept, and many such microscale devices are already working in animals. At least four major conferences on BioMEMS (Biological Micro Electronic Mechanical Systems) deal with devices to be used in the human bloodstream.
¹⁴⁹

Consider several examples of nanobot technology, which, based on miniaturization and cost-reduction trends, will be feasible within about twenty-five years. In addition to scanning the human brain to facilitate its reverse engineering, these nanobots will be able to perform a broad variety of diagnostic and therapeutic functions.

Robert A. Freitas Jr.—a pioneering nanotechnology theorist and leading proponent of nanomedicine (reconfiguring our biological systems through engineering on a molecular scale), and author of a book with that title
¹⁵⁰
—has designed robotic replacements for human blood cells that perform hundreds or thousands of times more effectively than their biological counterparts. With Freitas’s respirocytes (robotic red blood cells) a runner could do an Olympic sprint for fifteen minutes without taking a breath.
¹⁵¹
Freitas’s robotic macrophages, called “microbivores,” will be far more effective than our white blood cells at combating pathogens.
¹⁵²
His DNA-repair robot would be able to mend DNA transcription errors and even implement needed DNA changes. Other medical robots he has designed can serve as cleaners, removing unwanted debris and chemicals (such as prions, malformed proteins, and protofibrils) from individual human cells.

Freitas provides detailed conceptual designs for a wide range of medical nanorobots (Freitas’s preferred term) as well as a review of numerous solutions to the varied design challenges involved in creating them. For example, he provides about a dozen approaches to directed and guided motion,
¹⁵³
some based on biological designs such as propulsive cilia. I discuss these applications in more detail in the next chapter.

George Whitesides complained in
Scientific American
that “for nanoscale objects, even if one could fabricate a propeller, a new and serious problem would emerge: random jarring by water molecules. These water molecules would be smaller than a nanosubmarine but not much smaller.”
¹⁵⁴
Whitesides’s analysis is based on misconceptions. All medical nanobot designs, including those of Freitas, are at least ten thousand times larger than a water molecule. Analyses by Freitas and others show the impact of the Brownian motion of adjacent molecules to be insignificant. Indeed, nanoscale medical robots will be thousands of times more stable and precise than blood cells or bacteria.
¹⁵⁵

It should also be pointed out that medical nanobots will not require much
of the extensive overhead biological cells need to maintain metabolic processes such as digestion and respiration. Nor do they need to support biological reproductive systems.

Although Freitas’s conceptual designs are a couple of decades away, substantial progress has already been made on bloodstream-based devices. For example, a researcher at the University of Illinois at Chicago has cured type 1 diabetes in rats with a nanoengineered device that incorporates pancreatic islet cells.
¹⁵⁶
The device has seven-nanometer pores that let insulin out but won’t let in the antibodies that destroy these cells. There are many other innovative projects of this type already under way.

M
OLLY
2004:
Okay, so I’ll have all these nanobots in my bloodstream. Aside from being able to sit at the bottom of my pool for hours, what else is this going to do for me?

R
AY
:
It will keep you healthy. They’ll destroy pathogens such as bacteria, viruses, and cancer cells, and they won’t be subject to the various pitfalls of the immune system, such as autoimmune reactions. Unlike your biological immune system, if you don’t like what the nanobots are doing, you can tell them to do something different
.

M
OLLY
2004:
You mean, send my nanobots an e-mail? Like, Hey, nanobots, stop destroying those bacteria in my intestines because they’re actually good for my digestion?

R
AY
:
Yes, good example. The nanobots will be under our control. They’ll communicate with one another and with the Internet. Even today we have neural implants (for example, for Parkinson’s disease) that allow the patient to download new software into them
.

M
OLLY
2004:
That kind of makes the software-virus issue a lot more serious, doesn’t it? Right now, if I get hit with a bad software virus, I may have to run a virus-cleansing program and load my backup files, but if nanobots in my bloodstream get a rogue message, they may start destroying my blood cells
.

R
AY
:
Well, that’s another reason you’ll probably want robotic blood cells, but your point is well taken. However, it’s not a new issue. Even in 2004, we already have mission-critical software systems that run intensive-care units, manage 911 emergency systems, control nuclear-power plants, land airplanes, and guide cruise missiles. So software integrity is already of critical importance
.

M
OLLY
2004:
True, but the idea of software running in my body and brain seems more daunting. On my personal computer, I get more than one hundred spam messages a day, at least several of which contain malicious software
viruses. I’m not real comfortable with nanobots in my body getting software viruses
.

R
AY
:
You’re thinking in terms of conventional Internet access. With VPNs (private networks), we already have the means today to create secure firewalls—otherwise, contemporary mission-critical systems would be impossible. They do work reasonably well, and Internet security technology will continue to evolve
.

M
OLLY
2004:
I think some people would take issue with your confidence in firewalls
.

R
AY
:
They’re not perfect, true, and they never will be, but we have another couple decades before we’ll have extensive software running in our bodies and brains
.

M
OLLY
2004:
Okay, but the virus writers will be improving their craft as well
.

R
AY
:
It’s going to be a nervous standoff, no question about it. But the benefit today clearly outweighs the damage
.

M
OLLY
2004:
How clear is that?

R
AY
:
Well, no one is seriously arguing we should do away with the Internet because software viruses are such a big problem
.

M
OLLY
2004:
I’ll give you that
.

R
AY
:
When nanotechnology is mature, it’s going to solve the problems of biology by overcoming biological pathogens, removing toxins, correcting DNA errors, and reversing other sources of aging. We will then have to contend with new dangers that it introduces, just as the Internet introduced the danger of software viruses. These new pitfalls will include the potential for selfreplicating nanotechnology getting out of control, as well as the integrity of the software controlling these powerful, distributed nanobots
.

M
OLLY
2004:
Did you say reverse aging?

R
AY
:
I see you’re already picking up on a key benefit
.

M
OLLY
2004:
So how are the nanobots going to do that?

R
AY
:
We’ll actually accomplish most of that with biotechnology, methods such as RNA interference for turning off destructive genes, gene therapy for changing your genetic code, therapeutic cloning for regenerating your cells and tissues, smart drugs to reprogram your metabolic pathways, and many other emerging techniques. But whatever biotechnology doesn’t get around to accomplishing, we’ll have the means to do with nanotechnology
.