MEDICAL APPLICATION OF NANO-TECHNOLOGY
(b).
ABSTRACT:
Nano
technology involves manufacturing of material components, devices and systems
at near atomic scale, or nanometer level. Designing and creating at this scale
leads to products that can achieve exceptional performance. Battery materials
storing large amounts of energy, structural materials increasing life of an
engine ten times, super fast computer chips, nanorobots bringing the images of
whole body including blood vessels etc and many more. The present paper deals
with application of nano in field of medicine. In the field of medicine it is
used for bio-compatibility, research and monitoring, intervention of surgery or
drugs, replacement of organs and prevention of rejection, replacement of
injured organs, heterostasis and much more. There are however limitations as it
is a technology and not a magic. Also, cure to some diseases have been found.
They are telomere loss, chemical accumulation
DNA damage, cancer, brain damage, hormonal deficiencies, solving accident cases
and many blood related diseases. Some ethical issues also govern the
advancement of this technology. Many factors like genetic modification, over
population, poor health , elitism and other risks are opposed by many people.
Finally, this is a new technology and still many frontiers lie unconquered.
(1) WHAT IS NANOTECHNOLOGY ?
Nanotechnology, simply put, is the creation of
materials, components, devices and systems at the near-atomic, or nanometer,
level. A nanometer is a unit of length roughly equivalent to ten atoms placed
side by side. Designing and creating materials at this scale often leads to
products which can achieve exceptional performance. Imagine battery materials
that store enormous amounts of energy, structural materials that increase the
lifetime of engine components by a factor of ten, electronic materials that
enable super-fast computer chips, and many, many others. These are the
potential benefits and applications of nanotechnology.
Components and systems are being
designed and fabricated at sizes never before considered possible. Above is a
picture of gears that are part of a MEMS (MicroElectroMechanical System)
micromotor. Each gear tooth is one-tenth the diameter of a human hair.
The
definition is indeed slippery. Some of nanotechnology isn't nano, dealing
instead with structures on the micron scale (millionths of a meter), 1,000
times or more larger than a nanometer. Also, nanotechnology, in many cases,
isn't technology. Rather it involves basic research on structures having at
least one dimension of about one to several hundred nanometers. (In that sense,
Einstein was more a nanoscientist than a technologist.) To add still more
confusion, some nanotechnology has been around for a while: nano-size carbon
black particles (a.k.a. high-tech soot) have gone into tires for 100 years as a
reinforcing additive, long before the prefix "nano" ever created a
stir. For that matter, a vaccine, which often consists of one or more proteins
with nanoscale dimensions, might also qualify.
Real-world nano, fitting Roco's
definition, does exist. Sandwiching several nonmagnetic layers, one of which is
less than a nanometer thick, between magnetic layers can produce sensors for
disk drives with many times the sensitivity of previous devices, allowing more
bits to be packed on the surface of each disk. Since they were first introduced
in 1997, these giant magnetoresistive heads have served as an enabling
technology for the multibillion-dollar storage industry
(2)
WHY ONLY NANOTECH. ?
There
is a there there in both nanoscience
and nanotechnology. The nanoworld is a weird borderland between the realm of
individual atoms and molecules (where quantum mechanics rules) and the
macroworld (where the bulk properties of materials emerge from the collective
behavior of trillions of atoms, whether that material is a steel beam or the
cream filling in an Oreo). At the bottom end, in the region of one nanometer,
nanoland bumps up against the basic building blocks of matter. As such, it
defines the smallest natural structures and sets a hard limit to shrinkage: you
just can't build things any smaller.
Nanotechnology
will change the way we live. Dr. Richard Feynman, one of this century's leading
scientists, delivered a lecture in 1959 entitled There is Plenty of Room at the
Bottom. Feynman postulated a vision of what might be achieved if one could
create materials and devices at an atomic or molecular level.
That
vision has grown to the point that nanotechnology is of such importance to the
future growth and security of our nation that a federal initiative (National
Nanotechnology Initiative) has been established and is overseen by the National
Science and Technology Council. The Government is providing funding to
stimulate the development of the academic and industrial resources necessary to
achieve nanotechnology's potential.
(3) HISTORY OF NANOTECHNOLOGY:-
Any advanced research carries inherent
risks. But nanotechnology bears a special burden. The field's bid for
respectability is colored by the association of the word with a cabal of
futurists who foresee nano as a pathway to a techno-utopia: unparalleled
prosperity, pollution-free industry, even something resembling eternal life.
In
1986-five years after IBM researchers Gerd Binnig and Heinrich Rohrer invented
the scanning tunneling microscope, which garnered them the Nobel Prize-the book
Engines of Creation, by K. Eric Drexler, created a sensation for its depiction
of godlike control over matter. The book describes self-replicating
nanomachines that could produce virtually any material good, while reversing
global warming, curing disease and dramatically extending life spans.
Scientists with tenured faculty positions and NSF grants ridiculed these
visions, noting that their fundamental improbability made them an absurd
projection of what the future holds.
But the visionary scent that has
surrounded nanotechnology ever since may provide some unforeseen benefits. To
many nonscientists, Drexler's projections for nanotechnology straddled the
border between science and fiction in a compelling way. Talk of cell-repair
machines that would eliminate aging as we know it and of home food-growing
machines that could produce victuals without killing anything helped to create
a fascination with the small that genuine scientists, consciously or not, would
later use to draw attention to their work on more mundane but eminently more
real projects. Certainly labeling a research proposal
"nanotechnology" has a more alluring ring than calling it
"applied mesoscale materials science."
Less
directly, Drexler's work may actually draw people into science. His imaginings
have inspired a rich vein of science-fiction literature . As a subgenre of
science fiction-rather than a literal prediction of the future-books about
Drexlerian nanotechnology may serve the same function as Star Trek does in
stimulating a teenager's interest in space, a passion that sometimes leads to a
career in aeronautics or astrophysics.
The danger comes when intelligent
people take Drexler's predictions at face value. Drexlerian nanotechnology drew
renewed publicity last year when a morose Bill Joy, the chief scientist of Sun
Microsystems, worried in the magazine Wired about the implications of
nanorobots that could multiply uncontrollably. A spreading mass of
self-replicating robots-what Drexler has labeled "gray goo"-could
pose enough of a threat to society, he mused, that we should consider stopping
development of nanotechnology. But that suggestion diverts attention from the
real nano goo: chemical and biological weapons.
Among real chemists and materials
scientists who have now become nanotechnologists, Drexler's predictions have
assumed a certain quaintness; science is nowhere near to being able to produce
nanoscopic machines that can help revive frozen brains from suspended
animation. (Essays by Drexler and his critics, including Nobel Prize winner
Richard E. Smalley, appear in this issue.) Zyvex, a company started by a
software magnate enticed by Drexlerian nanotechnology, has recognized how
difficult it will be to create robots at the nanometer scale; the company is
now dabbling with much larger micromechanical elements, which Drexler has
disparaged in his books
(4) MEDICAL TECHNIQUES USING NANOTECHNOLOGY:-
Medical theory and technique today are
a vast improvement over the state of the art a century ago. However, by
comparison with what could be, medical practice today can only be described as
primitive. Surgery creates huge wounds which require days to heal.
Cancer therapy usually aims to be as destructive as possible, without wiping
out anything too important. Most of our drugs were discovered by trial
and error, and their side effects are sometimes drastic. Organ
transplantation requires crippling the immune system. Many conditions
cannot be cured at all. The good news is that even basic nanotechnology
can correct most if not all of these problems.
1. BIOCOMPATIBILITY
Any medical nanobot will have to
interact closely with the chemicals of the body. Whatever the robot is
built of, its surface must not provoke an allergic response. Most medical
applications will require the detection and/or release of chemicals. The
outside of a nanobot will be immersed in fluid, but the inside will probably be
dry, at least with some types of mechanism. The interface between a
nanomachine and the chemical environment of the body will form a large part of
the design.
Carbon is an extremely versatile
molecule; it can form linear or zig-zag chains, rings (benzene and other
aromatic compounds), buckyballs (spherical molecules), sheets (graphite and
buckytubes), or blocks (diamond). Chemists have been able to bond organic
molecules to each of these forms of carbon, so we will be able to design the
surface separately from the workings of the nanobot. We have been
implanting gizmos into the body for decades, so we already know some materials
we can use to make biocompatible surfaces. We can design surfaces that
will remain separate from the body's tissues, or that will attract tissues such
as bones or blood vessels to attach to them. Future research will give us
more flexibility, but what we have today is good enough for most
applications. Recently, researchers have even been able to make neurons
grow through holes in a silicon chip, for the purpose of sensing the signals.
Each chemical compound has a certain
characteristic shape, and also a pattern of electric charge on its
surface. A pocket or pit of the same shape and lined with the opposite
charge pattern will attract the desired chemical. This can be used to
sense the presence of the chemical. If the pit is movable, it can be
rotated inside the machine to take in chemicals for processing--a close-fitting
pit would exclude most or all of the water and undesired chemicals, and deliver
the desired chemical precisely packaged for the interior mechanism to work
on. Likewise, a substance synthesized inside the machine can be moved
outside; deforming the pit or changing the pattern of charge will make the
chemical float away. Antibodies are nature's version of such pits; they
attach themselves to chemicals with amazing specificity. Artificial pits
or "binding sites" that attract specific molecules have been
constructed.
Biotech researchers are already
extracting molecular motors of several types from cells, and building systems
to test the capabilities of the motors. Other researchers are building
intricate shapes out of DNA molecules--an application nature never planned for,
but potentially useful nevertheless. Our "designer's toolbox"
will be stocked with a variety of useful parts even before we start fabricating
artificial shapes.
2. RESEARCH AND MONITORING
A problem can't be corrected unless it
is first detected. One of the first contributions nanotech will make to
medicine is in the area of research. Miniaturization will create probes
that gather orders of magnitude more data. Chemical sensors can be built
small enough to put inside living cells. Probes may be thin enough to go
through tissue without causing noticeable injury. Small, low-power
devices may be implanted for continuous monitoring.
The human genome project will prove
invaluable for understanding the biotechnology of the body; however, the genome
is only a static record of what proteins the body is capable of making, and
what molecular switches enable their manufacture. Information about the
actual concentrations of proteins in living cells during the body's normal
operation would be equally valuable. Such measurements could not be made
today, but would be feasible with nanotech sensors capable of fitting inside
single cells.
In order to detect the state of the
body, information from thousands or millions of sensors would need to be
coordinated. A Pentium-class nanocomputer could fit in 1/1000 the volume
of a single cell. There are several ways that sensors can communicate,
among themselves and with computers outside the body.
Miniaturization and efficiency would
allow implanted sensors to be used full-time. Full-time sensors could
detect medical problems before they became serious. In conjunction with
other technologies, continuous monitoring could allow the full-time maintenance
of a state of good health. Permanent implants could also interact
directly with our fast systems, giving the body a continuous tuneup.
3. INTERVENTION
Medical intervention generally consists
of either surgery or drugs. To reach an area inside the body, the body
must be cut somewhere. Drugs are usually delivered to the entire body at
once. Most medical interventions today are designed to fix a specific
problem, and are applied after the problem has already developed.
State of the art surgical technique
uses instruments inserted through small tubes placed in small incisions.
These instruments are necessarily simple; for example, a gripper or a
blade. Although surgical robots are coming into use for certain delicate
operations, the robots are considerably bigger than the area they operate
on. We don't yet have robots that could fit through the tubes and do
complicated operations on-site. Nanotech can eliminate this
problem. The smallest acupuncture needle is 120 microns, or about as wide
as twelve cells. 120 microns is 2,400 times as wide as a flagellar or electrostatic
motor. A remarkably complex surgical robot could thus be inserted through
a hole so small it doesn't even bleed.
Nanobots will probably be able to
stitch tissue together at a cellular/molecular level, greatly accelerating the
wound-healing process. This means that if large incisions are required,
for example to replace whole organs, they can be repaired as part of the
surgery. Accidental trauma will also be relatively easy to fix.
The normal way to deliver a chemical
today is to dump it into either the bloodstream or the stomach, and let it
spread all through the body. For some chemicals, such as insulin, this is
appropriate. But for others, such as chemotherapy drugs and some
antibiotics, it is best to keep them as local as possible. Nanosurgical
techniques can put drug delivery devices right where they are needed. The
devices can be numerous and tiny, so that they can be inserted into any
organ. In most cases, the devices could manufacture the required
chemicals on the spot, using elements and energy from the surrounding tissue,
thus eliminating the need for holding tanks and external supply. (Nature
has demonstrated that a complex chemical factory can fit into the space of a
bacterium.)
4. REPLACEMENT
If an organ fails, we must either
replace it or do without. Usually the replacement organ comes from
someone else, which means that the body will reject it unless drugs are taken
to cripple the immune system. Today several organs, including the larynx
and the bladder, have been grown on special scaffolding. With nanotech to
build far more complex and precise scaffolding, we will be able to create most
organs this way from the patient's own cells, thus allowing rejection-free
transplantation.
Artificial organs will become far more
feasible. Today, artificial hearts have been used in a few cases, and the
use of external artificial kidneys (dialysis) is common. These devices
don't work very well, though they are certainly better than nothing.
However, a nanotech-built device could use the body's own energy
supply--glucose and oxygen--for power, and could be far more sensitive and
responsive to the body's condition.
5. REPAIR
Today, if a tissue is torn or cut, we must simply wait for the body to repair it. The most we can do to help is to hold the torn edges together with stitches or surgical glue. As mentioned above, nanobots should be able to re-form the molecular bonds that hold cells together, and thus repair wounds almost immediately.
Another form of injury is oxygen
deprivation. Due to a blood clot or broken blood vessel, a tissue may be
starved of oxygen. Normally this causes cells to kill themselves within
minutes. However, drugs have already been found that tell the cells not
to give up so soon; in early trials, they seem to cause significant improvement
in stroke victims. A population of nanobots scattered throughout the
tissues could provide more timely and targeted release of such drugs, and could
also store a few minutes worth of oxygen in pressurized tanks (see "Respirocytes
and Their Uses in Future Nanomedicine," Chapter ) to keep the tissue alive
until the wound repair machines can fix the problem.
6. HETEROSTASIS
The body maintains its condition by a
mechanism called homeostasis. There are hundreds of signals controlling
hundreds of mechanisms, so that if part of the body starts to get out of sync
with the others it is forced back in line. For the most part, these
signals are sent by either chemical or neural signals. There is no
overall control, and some of the signals cause undesired side effects.
Heterostasis is the idea that different
parts of the body can be maintained deliberately out of sync with each
other. For example, it appears that some immune diseases such as asthma
may be caused by a lack of parasites. At least one doctor has
deliberately infected himself with tapeworm in an effort to improve his immune
function. Rather than go to such lengths, it may be possible to modify
local chemical concentrations and/or the body's sensors for those chemicals, so
that different systems have a slightly different picture of what's going
on. It will take a lot of research to find what combinations of state are
best, but it seems clear that our bodies are naturally optimized for a
lifestyle different from the one we have chosen, and heterostasis may be a way
to improve health.
Heterostasis may also be useful when
modifying individual organs. Rather than trying to design a new organ to
function precisely like the one it replaces, it may be easier to tweak the body's
other systems so that they react correctly to the change. This also
raises the possibility of maintaining different organs at different
physiological ages for peak
performance--a 90-year-old person might be healthiest with a ten-year-old liver
but a 25-year-old heart.
The most extreme type of heterostasis
would involve the separation of the body's components into independent
subsystems, temporarily preventing all signaling between them. This would
be an aggressive but straightforward treatment for massive damage or other
dysfunction, in which part of the body was damaged enough to make the rest
ill. Today, we can keep many organs alive for hours or even days outside
the body, and we can keep the body alive for hours on a heart-lung machine.
Our technology is incredibly crude in comparison with a nanotech-built
interface that could simulate a healthy body in great detail. Each organ
or system could thus be stabilized and repaired (or replaced) individually,
without any harmful or unexpected messages from the other organs. Once
everything was working well, the state of each organ would be synchronized,
connections would be restored, and the body would be whole again.
(5) LIMITATIONS OF MEDICAL NANOTECH
Nanotech is technology, not
magic. Although it can do a lot, there are some limits. The biggest
limit will probably be waste heat. The body can usually dump about 100
watts of extra power without sweating. This sounds like a lot, but
remember that nanotech motors can be far more powerful than biological
ones. A single cell-sized cluster of nanotech motors could use ten
watts! (Of course it would immediately overheat and burn out.) When
it comes time to choose which medical devices to install in your body, you will
be limited by a power budget.
Another limitation is space. Most
of us imagine a cell as a bag full of watery stuff, but in fact a cell is quite
full of chemicals and structural proteins. A nanobot will need to be
carefully designed to avoid disrupting the mechanism, especially if it needs to
move around. The good news is that some bacteria can hide in our cells,
so we know it can be done.
(6) DISEASES AND CURES:-
(6) DISEASES AND CURES:-
Medical science has scored some impressive successes. Diseases caused by bacteria have been greatly reduced by antibiotics. Vitamin and mineral deficiency diseases are almost unknown, at least in developed nations. However, we still have many diseases that limit our lifespan, and that medicine can only postpone, not cure. Life cannot be extended indefinitely without curing each disease that threatens to shorten it. This section will explore several of the worst problems and how nanotech can be used to cure them.
1. TELOMERE LOSS
Most cells have a length of DNA called
the "telomere" that gets shorter each time they divide. After a
certain number of divisions, the telomere is gone, and they die. (This is
probably an anti-cancer mechanism.) If life is to be extended, cells will
need to have their telomeres replaced so that they can keep working. We
know that cancer cells have managed to avoid the telomere trap, and we already
know of an enzyme that performs this function. It should be simple to
induce a cell to lengthen its telomeres, using a machine built on the same
scale as the cell that can sense its state and dispense the right chemicals at
the right time.
2. CHEMICAL ACCUMULATION
One cause of cell death is accumulation
of harmful chemicals. The most famous type of chemical is the prion, a
malformed protein that cannot be removed by the body and that causes normal
protein to turn into prions. Prions are responsible for Mad Cow disease
and similar human diseases. It is unclear how many other problems may be
caused by the accumulation of other non-digestible chemicals. What is
clear is that a diamond nanobot could make short work of breaking up a prion,
or any other chemical that the body couldn't deal with on its own.
Nanobots could go from cell to cell like a housecleaning service, absorbing and
breaking down a variety of undesired chemicals.
3. DNA DAMAGE
Our genetic material is under constant
attack from radiation and chemicals. Damage accumulates and causes cells
to malfunction. This can be corrected in several ways. First, cells
other than neurons that are malfunctioning can usually be killed; the body will
replace them with no ill effects. In fact, cells contain several
mechanisms for killing themselves if they detect that they are not working
right. (Stem cells and other techniques can help if the body is slow to
replace the missing cells.) Second, it should be possible to minimize
damage by vacuuming up the chemicals that cause mutation, and by manipulating
the cell's state to increase the amount of energy it spends on
self-repair. Third, a nanomachine may scan each cell's DNA to search for
and repair damage, or perhaps simply replace chromosomes periodically with new
error-free copies.
4. CANCER
At a cellular level, cancers are
usually quite different from normal tissue. Many cancer cells actually
change the chemicals on their surface, so are easy to identify. Most of
the rest grow faster or change shape. And every cancer involves a genetic
change that causes a difference in the chemicals inside the cell.
The immune system already takes
advantage of surface markers to destroy cancer cells; however, this is not
enough to keep us cancer-free. Nanobots will have several
advantages. First, they can physically enter cells and scan the chemicals
inside. Second, they can have onboard computers that allow them to do
calculations not available to immune cells. Third, nanobots can be
programmed and deployed after a cancer is diagnosed, whereas the immune system
is always guessing about whether a cancer exists. Nanobots can scan each
of the body's cells for cancerous tendencies, and subject any suspicious cells
to careful analysis; if a cancer is detected, they can wipe it out quickly,
using more focused and vigorous tactics than the immune system is designed for.
5. BRAIN DAMAGE
The brain is unique among the body's
organs: it stores our memories and personality, so that it cannot simply be
replaced if it starts to wear out. This poses a special problem for life
extension: the information stored in the brain must be preserved over extended
periods of time, safe from disease and accident.
Obviously it is good to prevent the
premature death of neurons. Poisons such as alcohol, accidents such as
stroke, and diseases such as Alzheimer's can all cause neurons to die. In
each of these cases, neuron death can be greatly slowed if not prevented
entirely by controlling the chemistry inside the cell. Injurious
chemicals can be vacuumed up and converted into harmless ones. Damaged
neurons, like other cells, sometimes go into suicide mode (called
"apoptosis"); as mentioned above, this can be chemically prevented,
and the neuron can be stabilized until the problem is fixed and the damage is
repaired. It is now known that brain cells do regenerate: the brain is adding
new ones all the time. This implies that some neural death is
normal. How do the new cells know how to behave? It seems that a
new neuron can take its cues from the existing ones; this means that a person's
mind may be intact even after the death and replacement of a large percentage
of their neurons.
Finally, it may be possible to measure
neural connections and/or activity in enough detail to simulate the firing
pattern. This may make it possible to create an artificial neuron or even
an artificial neural net that can be used to replace missing neurons and retain
old memories. But even if this proves to be impossible, the worst-case
scenario is one in which people can't remember much farther than a century
back. We accept more memory loss than this as a natural consequence of
aging.
6. HORMONE DEFICIENCY
Aging is associated with changes in the
levels of many hormones; perhaps the best known example is menopause, which is
caused by a reduction in estrogen. It is likely that treating glands
against aging at the cellular level would restore age-appropriate hormone
production. However, if this is not enough to bring the body to a younger
state, artificial glands could be built that would maintain the desired hormone
levels. In fact, different hormone levels could be supplied to different
organs--something that the body cannot do for itself. This would be an
example of heterostasis.
INFECTION
Bacteria, viruses, and parasites are
continuing problems. Antibiotics work well against most bacteria;
however, antibiotic-resistant strains are developing. Since viruses
aren't active until they take over a cell, they are immune to antibiotics, and
medicine cannot yet do much against them. There are many kinds of
parasites that may need individual medical techniques.
Our immune system is quite effective at
dealing with most infections. However, it needs to learn by
experience--it is generally most effective at fighting organisms that it can
recognize on a molecular level. Diseases can be very clever in evading
it. Some diseases, such as Ebola, progress too rapidly for the immune
system to respond. Syphilis survives by being stealthy and surrounding
itself with the body's own chemicals to camouflage itself. Herpes splices
itself into the genes of the body's cells, so the immune system can't detect it
and wipe it out. HIV directly attacks the immune system.
Nanobots have several advantages over
the immune system. They will not be susceptible to attack by natural
pathogens. They will have computational resources unavailable to immune
cells. They can be programmed to find and fight diseases they have never
encountered--when a new disease shows up, as soon as it is analyzed everyone's
nanobots can benefit. Likewise, the system can be activated based on
external knowledge of the likelihood of a disease; the nanobots won't have to
waste energy looking for malaria in winter. Nanotech will give us more
options for cleaning up after a disease, since corrupted genes will be
repairable without killing the affected cell.
Some diseases, such as cholera and
tetanus, live in the environment; without scrubbing the whole earth, we can't
get rid of them entirely, so we will need to maintain an immune system against
them. But many diseases can't survive without humans to infect.
With great effort, we managed to eradicate smallpox using 1970's technology.
Cheap manufacturing would allow the creation of billions of doses of highly
effective treatments that would be easy to distribute and administer; the main
obstacles to wiping out many diseases worldwide would be political, not
economic or technological.
7.ACCIDENTS
Accidents, especially motor vehicle
accidents, are a leading cause of death at all ages. Although an accident
is not itself a disease, it kills by producing damage to the body, and that
damage can be treated or prevented like any other disease. Most accidents
involve mechanical injury (trauma); most of the rest involve chemical injury,
either poisoning or oxygen starvation. A permanent nanobot installation
can make many accidents survivable that would be fatal today.
Nanobots embedded in tissue can strengthen
it against tearing, or repair it if it does tear. It is common for a blow
to the head to rattle the brain against the skull; a specially shaped
nano-built device could cushion the brain, preventing this damage. Other
devices could vacuum up common poisons before they could cause damage, or
barricade poisoned areas to keep the poison from spreading through the
body. Respirocytes could allow the body to function normally for several
minutes without breathing or circulation, giving more opportunity to restore
normal functioning. In cases of extreme injury, heterostasis could be
used to stabilize the body until help can arrive. As long as the brain is
not physically damaged, it can be functionally separated from the body and
forced into a low-power state. With today's medicine, paramedics refer to
the "golden hour": if an accident victim can be brought to a hospital
in less than an hour, chance of survival is greatly increased. People
have recovered after drowning in cold water for over an hour; artificial
mimicry of this state, combined with the ability to aggressively repair the
body, might extend the "golden hour" significantly.
8. BLOOD RELATED DISEASES
Many diseases, from heart attacks and
strokes to sepsis and metastasizing cancer, involve the blood in some
way. The author has proposed an aggressive nanomedical device, a "Vasculoid", that would replace the
blood volume and take over its functions by lining the entire vascular system
with a multi-segmented robot. In addition to preventing many diseases,
and limiting the scope of others (such as poisoning), such a system would
provide detailed control of the body's chemical environment around each
individual capillary, allowing heterostasis to be used extensively.
The Vasculoid is extremely complicated
and would require much research to build and use successfully. This
particular device may never be used, but it can provide a hint of the
possibilities inherent in advanced nanomedicine.
(7) ETHICAL ISSUES:-
1. GENETIC MODIFICATION
It is likely that some conditions will
be treated most easily by modifying the body's genetic material. Many
people are disturbed by this idea, especially if the modification is
transmissible to offspring. However, once we have a nanotechnology that
can directly manipulate the genes, transmission of modified genes need not be a
cause for concern. Any genetic manipulation that turns out to be a bad
idea will be reversible. Furthermore, it would be trivial to edit the DNA
of any offspring while still in embryo stage in order to remove the
modifications. The idea that a genetic modification will irreversibly
change the whole species becomes incorrect once genes can easily be directly manipulated.
2. OVERPOPULATION
A common objection to life extension is
that if everyone lives forever, the earth will become overcrowded.
However, a little math will demonstrate that the earth can become overcrowded
much faster due to excess births than due to reduced death. If everyone
killed themselves after 80 years of life, that act would remove only one person
from the population; meanwhile their children and grandchildren would be
reproducing. But a person who chose to live a long time and have one
fewer child would be reducing the population by more than one, since a
nonexistent person can't have children. (Robert J. Bradbury points out
that nanotechnology will also give us cheaper access to space. Using a
fairly basic design (see references), it would be feasible for earth's entire
population to leave the earth and live in space.)
3. POOR HEALTH
Today, people are kept alive for years
in terrible health, sometimes beyond the point where they wish to die.
This has given life extension a bad reputation. Merely extending life
without improving health is often a bad idea. The good news is that if
health is improved, life will naturally be extended. Once we have the
technology to eliminate diseases, we need no longer worry about living on in
bad health.
4. ELITISM
It has been argued that it would be
selfish for some people to extend their lives when the technology is not
available to everyone. However, life extension will not be a single
technology hoarded by an elite--instead, it will be a natural consequence of
health maintenance. Inequities in availability of health care are
widespread today, and curing more diseases will not make the problem
worse. On the other hand, development of more effective medical tools
will reduce the cost of medical care. If you want to increase the
availability and reduce the cost of a technology, you should invest in research
and development, and buy more technology. The more people who make use of
health maintenance technologies, the faster they will become cheap and widely
available. (Several large private foundations are working to make medical
care widely available in the developing world.)
5. OTHER RISKS
Some people have claimed that nanotech
itself is extremely risky, and thus any development or use of it must be
constrained. This argument rests on the idea that tiny self-replicating
nanobots appear to be possible, and that a rogue self-replicator could eat the
planet. This argument does not apply to medical nanotech. There is
no reason to use self-replication for medical nanodevices; it would only make
them needlessly complex and more prone to failure. A medical nanodevice
would simply be a machine like any other, no more capable of running amok than
a television. The factories used to build the nanobots might be
self-replicating, but a factory is equally unlikely to run amok.
The biggest risk of life extension is
that it might be delayed. Currently, fifty-five million people die each
year. Most of these deaths are untimely: the person dying would rather not
die yet. Taken together, these deaths are an unimaginable tragedy.
The sooner we develop life extension, the sooner we can save lives.
Without it, six billion people alive today will be dead before the year 2100.
The second big risk is that life extension
and related technologies will give us more choice than we are comfortable
with. If life extension is as simple as taking a pill once a month, then
not taking the pill is tantamount to suicide. In Western culture, suicide
is cause for horror. How will we deal with it when people decide after
100 or 200 years that they are simply done living? There is no easy
answer to this question. Another choice that we will face is what age to
make ourselves. We know that hormones affect our mental functioning,
which makes the choice even more important. We currently have no basis
for making such a choice.
The third risk is actually not a risk
at all--we just think it is. We have the idea that "There's no such
thing as a free lunch" and "You can't get something for
nothing." This idea, that every good thing has a price, is deeply
rooted in American culture. I like to call it the Puritan Work Ethic; it
makes us suspicious of anything that sounds too good to be true. But the
Puritan Work Ethic has been outdated since the Industrial Revolution: the
entire basis of our economy is that wealth can be created. Scientific
research and technological developments create massive amounts of wealth and
other goodness simply by the exercise of our intelligence.
CONCLUSIONS
Nanotechnology is relatively new field
of research and most of the developments
in this are being worked upon in laboratories. As Nanotechnology involves
manufacturing at molecular level, it was considered as a field too ambitious to
be taken up. However, recent developments have shown that such processes are
very much feasible as well as safe for humans. Besides medical field,
Nanaotechnology is fast emerging in many other fields like (biochip protein
memory), communications tec
References:
-
www.scientificamerican.com
-
www.nanotechnology.com
-
www.electronicsforu.com
A
REPORT ON
MEDICAL APPLICATIONS
OF
NANOTECHNOLOGY
BY:
SAURABH BHATIA
6TH EC
CU SHAH COLLEGE OF ENGG. AND TECHNOLOGY
WADHWAN CITY, GUJARAT
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