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Nanorobotics
A revolutionary new technology




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Abstract
Nanorobotics has sparked the fire for a      a talk entitled "There’s Plenty of Room
revolutionary new technology. While          at the Bottom". Feynman proposed using
much speculation has been published on       machine tools to make smaller machine
possible far-future applications of          tools, which, in turn, would be used to
nanorobotics using advanced materials        make still smaller machine tools, and so
and manufacturing techniques, relatively     on all the way down to the molecular
little has been published on applying        level. Feynman argued that these tools
existing engineering technology to the       could be applied to produce vast
problems in order to create a solution. In   quantities of ultra small computers and
this paper, we will describe a mobile        various microscale and nanoscale robots.
nanorobot that can be created with           He concluded that this is “a development
existing technology, which can travel        which I think cannot be avoided.” The
around the human body to treat and cure      vision of nanorobotics was thus born.
diseases as grave as HIV. We will
address and propose solutions to
problems such as size, method of entry
into the body, means of propulsion,
means of maintaining a fixed position
while operating, control of the device,
power source, means of locating
substances to be eliminated, means of
elimination and how to remove the
device from the body afterwards. We
also put forth numerous applications of
nanorobots inside our body.



                                             Figure1. Nanorobots operating on RBC




1. Introduction                               The field of nanorobotics studies the
                                             design, manufacturing, programming,
Can you imagine using a bunch of
                                             and control of nanoscale robots. It is the
robots as a mouthwash , using them
                                             technology of creating machines or
to cure Alzheimer's or even better
                                             robots at or close to the scale of
imagine never having to grow old !!!
                                             nanometer (10-9 meters). Nanorobots are
Want to know how? Read on.                   typically devices ranging in size from
                                             0.1-10 micrometers and constructed of
  In 1959, the late Nobel Prize–winning      molecular components which have near
physicist Richard P. Feynman presented


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100% efficiency. At present nanorobots      and even potentially counteract the
are designed in virtual 3D graphical        ageing process.
environment in which nanorobots can be        We may see the first nanomedical
placed and can interact with other          materials and devices in use within the
nanorobots or their environment. The        next few years. Relatively simple
envisioned nanorobotic applications         nanodevices could soon offer cures for
range from medical to environmental         major conditions such as diabetes,
sensing to space and military               Alzheimer's or even Parkinson's disease.
applications. Some researchers believe      2.1. How do we introduce the device
this would cause a paradigm shift from      into the body?
treatment to prevention in the medical
community.                                    We need to find a way of introducing
                                            the nanomachine into the body, and
                                            allowing it access to the operations site
                                            without causing too much ancillary
                                            damage. We gain access via the
                                            circulatory system, which leaves us with
                                            a number of considerations.
                                               The first is that the size of the
                                            nanomachine determines the minimum
                                            size of the blood vessel that it can
                                            traverse. Therefore the smaller the
                                            nanomachine the better. However, this
                                            must be balanced against the fact that the
                                            larger the nanomachine the more
                                            versatile and effective it can be. This is
                                            especially important in light of the fact
Figure 2. Nanorobot description             that external control problems become
                                            much more difficult if we are trying to
                                            use multiple machines, even if they don't
                                            get in each other's way.
                                               The second consideration is an even
2. Nanorobots inside our body?              simpler one; we have to get it into the
   Machines the size of bacteria            body without being too destructive in the
(nanomachines) may be used to cure the      first place. This requires that we gain
human body of its various ills. This        access to a large diameter artery that can
application of nanotechnology to the        be traversed easily to gain access to most
field of medicine is commonly called as     areas of the body in minimal time.
nanomedicine.                               2.2 How do we move the device
    In just a few decades physicians        around the body?
could be sending tiny machines into our
bodies to diagnose and cure disease.           One of the first problems to solve is
These nanodevices will be able to repair    how to get our device to the problem
tissues, clean blood vessels and airways,   area . We start with a basic assumption:
transform our physiological capabilities,   we will use the circulatory system to
                                            allow our device to move about. We


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must then consider two possibilities: The
first possibility is to allow the device to
be carried to the site of operations by
means of normal blood flow. There are a
number of requirements for this method
to be practical. We must be able to
navigate the bloodstream; to be able to
guide the device so as to make use of the
blood flow. This also requires that there
be an uninterrupted blood flow to the
site of operations. Another problem with
this method is that it would be difficult
to remain at the site without some means      Figure 3. Locomotion subsystem
of maintaining position, either by means
of an anchoring technique, or by actively     2.3 How do we know where the device
moving against the current. While the         goes?
above objections do not eliminate any
possibility of using this technique, they       The next problem to consider is
do point out the need for at least a          exactly how to detect the problem tissue
supplementary means of locomotion.            that must be treated. The following
The second is active propulsion of our        methods can be employed:
device for which we can use :
                                              2.3.1. Long-range sensors can be used
      Propeller                              to allow us to navigate to the site of the
                                              unwanted tissue. We must be able to
      Cilia or flagellae                     locate a tumor, blood clot or deposit of
                                              arterial plaque closely enough so that the
      Electromagnetic pump                   use of short-range sensors is practical.
                                              These would be used during actual
      Jet Pump                               operations, to allow the device to
                                              distinguish between healthy and the
      Membrane propulsion                    unwanted tissue. Another important use
                                              for sensors is to be able to locate the
      Crawl along the walls of the           position of the nanorobot in the body.
       circulating system




                                                Figure 4. Sensor subsystems


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2.3.2 Ultrasonic sensors can be used in     obtain position information. This is only
two modes: In the active mode, an           practical for infrared or higher
ultrasonic signal is beamed into the        frequencies could be useful to obtain
body, and either reflected back, received   sufficiently accurate positional
on the other side of the body, or a         information.
combination of both. The received signal
is processed to obtain information about    2.4 How do we control the device?
the material through which it has passed.
                                               Consider the case of internal sensors
   In the passive mode, an ultrasonic
                                            for control. These sensors will be of two
signal of a very specific pattern is
                                            types. The first type will be used to do
generated by the nanorobot. By means of
                                            the final navigation. The second type of
signal processing techniques, this signal
                                            sensor will be used during the actual
can be tracked with great accuracy
                                            operation, to guide the nanorobot to the
through the body, giving the precise
                                            tissue that should be removed and away
location of the nanorobot at any time.
                                            from tissue that should not be removed.
2.3.3 Radioactive dye technique: This       2.4.1. Chemical control:
technique is basically one of
                                               Chemical sensors can be used to
illumination. A radioactive fluid is
                                            detect and trace chemicals in the
introduced into the circulatory system
                                            bloodstream and use the relative
and its progress throughout the body is
                                            concentrations of those chemicals to
tracked by means of a fluoroscope or
                                            determine the path to take to reach the
some other radiation-sensitive imaging
                                            unwanted tissue. Consequently, we
system. The major advantage of this
                                            would probably need a series of
technique is that it follows the exact
                                            nanorobots, one for each chemical, or at
same path that our nanorobot would take
                                            least a set of replaceable sensor modules.
to reach the operations site.
   The active form of this technique        2.4.2 Spectroscopic control:
would be to have a small amount of            This would involve taking continuous
radioactive substance as part of the        small samples of the surrounding tissue
nanorobot. This would allow its position    and analyzing them for the appropriate
to be tracked throughout the body at all    chemicals. This could be done either
times. Additionally, the technique would    with a high-powered laser diode or by
not require the nanorobot to use any        means of an electrical arc to vaporize
power, which would greatly simplify the     small amounts of tissue.
design of the nanorobot. We can fully
shield the radioactive substance and        2.4.3. TV camera control:
merely track its heat directly.                This method involves us having a TV
2.3.4. Radio/Microwave/Heat: A signal       camera in the device and transmitting its
is generated from outside the body and is   picture outside the body to a remote
allowed to reflect from or pass through     control station, allowing the people
tissues and the result interpreted. In      operating the device to steer it. One
order to use the technique to track the     disadvantage of this technique is the
nanorobot, a signal would need to be        relatively high complexity of the
generated by the nanorobot, detected        sensors.
outside the body, and interpreted to


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3. Means of treatment                         Unfortunately, the act of removing
   The treatment for each of the medical      cancerous cells to place them in the box
problems indicated above is the same in       could be dangerous
general; we must remove the tissue or         3.2. Physical trauma:
substance in question from the body. We
can use the nanorobot to physically              Another way of dealing with the
remove the unwanted tissue. We can also       unwanted tissues is by destroying them
use the nanorobot to enhance other            in situ. This would avoid damaging the
efforts being performed, and increase         cancerous cells and releasing chemicals
their effectiveness.                          into the bloodstream. In order to do this
3.1. Physical removal:                        effectively, we need a means of
                                              destroying the cell without rupturing the
    We can simply send the device to the      cell wall until after it is safe. The
site of the arteriosclerosis or blood clot,   following methods could be used:
scoop away sections of it, and have the
device carry the tissue out of the body             Resonant microwaves or
where it can be dissolved or destroyed.              Ultrasonics
Repeated applications of this technique
could remove most or all of a tumor with            chemical
minimal destruction to the surrounding
tissue and minimal spreading. In the case           Heat
of tumors, the act of physically
                                                    Microwave
shredding or even just breaking loose
clumps of cells can result in the cancer            Ultrasonic.
metastasizing throughout the body .One
possible solution is use of the sampling            Electrical resistance heating
box to destroy whatever is placed within
it.                                                 Laser
                                                 Rather than design a nanorobot
                                              capable of all techniques, we design a
                                              nanorobot that can have any of several
                                              "treatment modules" installed on it,
                                              allowing the same basic design to be
                                              used.

                                              4. Power
                                                 One major requirement for our
                                              nanorobot is, of course, power. We have
                                              to obtain the power from a source within
                                              the body, either by having a self-
                                              generating power supply, or by getting
                                              power from the bloodstream. The second
Figure 5. Cell surgery
                                              possibility is to have power supplied
                                              from a source external to the body.


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5. Control system                            7. Fields of application
  We need to steer the nanorobot to               Some interesting applications
where the sensors tell us it needs to be.       using nanorobots are as follows:
As always, the two choices are internal         To cure skin diseases, a cream
control and external. The following are         containing nanorobots may be used.
considerations:                                 It could remove the right amount of
                                                dead skin, remove excess oils, add
      Need to know where to go
                                                missing oils, apply the right amounts
      Need to know the route                   of natural moisturising compounds,
                                                and even achieve the elusive goal of
      Need to be able to correct if            'deep pore cleaning' by actually
       drawn off course                         reaching down into pores and
                                                cleaning them out
       Need to be able to apply
       treatment effectively

      Need to be able to reach outlet
       from body

      Need to compensate for the
       unexpected.

6. Means of recovery from the body
   ]
Given sufficiently accurate control of the
nano machine, we can just retrace our
path upstream. However, it would be a
lot easier, and recommended, to steer a
path through the body that traverses
major blood vessels and winds up at a
point where we can just filter the              Figure 6. Robots cleaning the teeth
nanomachine out of the bloodstream.
This will reduce the possibilities for
difficulties, and also cause less wear and
                                                 A mouthwash full of smart
tear on the nanomachine. Another
possibility is to have the nanomachine            nanomachines could identify and
anchor itself to a blood vessel that is           destroy pathogenic bacteria while
easily accessible from outside, and               allowing the harmless flora of the
perform a small surgical operation to             mouth to flourish in a healthy
remove it.                                        ecosystem. Further, the devices
                                                  would identify particles of food,
                                                  or tartar, and lift them from teeth
                                                  to be rinsed away. Being
                                                  suspended in liquid and able to
                                                  swim about, devices would be
                                                  able to reach surfaces beyond


                                                                                      7
   reach of toothbrush bristles or the
   fibers of floss

 Devices working in the
  bloodstream could nibble away
  at arteriosclerotic deposits,
  widening the affected blood
  vessels. Cell herding devices
  could restore artery walls and
  artery linings to health, by
  ensuring that the right cells and
  supporting structures are in the
  right places. This would prevent       
  most heart attacks.
                                                    Figure 7
 Artificial "biobots" could be
  designed to produce vitamins,              Bacterial adhesion on its surface
  hormones, enzymes or cytokines
  in which the host body was              Liver stones accumulate in the
  deficient, or they could be              bile duct. Nanorobots can be
  programmed to selectively                introduced into the bile duct and
  absorb and break down poisons            used to break up the liver stones
  and toxins. An artificial                as well. By continuing on up the
  mechanical cell called a                 bile duct into the liver, they can
  respirocyte, could be used to            clear away accumulated deposits
  keep a patient's tissues safely          of unwanted minerals and other
  oxygenated for up to about four          substances as well. This of
  hours if their heart has stopped         course, is true for the kidneys as
  beating.                                 well.

 Medical nanodevices could               Gout occurs when the breakdown
  augment the immune system by             products of various fats cannot
  finding and disabling unwanted           be removed from the
  bacteria and viruses. When an            bloodstream by the kidneys.
  invader is identified, it can be         When a nanorobot is in the
  punctured, letting its contents          bloodstream, it can locate these
  spill out and ending its                 deposits by means of a
  effectiveness. If the contents           combination of chemical sensors
  were known to be hazardous by            and external tracking, and can
  themselves, then the immune              break up the crystals, allowing
  machine could hold on to it long         the bloodstream to carry them
  enough to dismantle it more              away which will alleviate the
  completely.                              symptoms for a time.

                                          The nanorobots can be used to
                                           clean wounds and burns. They
                                           can be used to do a more



                                                                                 8
   complete and less traumatic job             including bacteria, viruses or
   than conventional techniques.               fungi.

 The nanorobots can also be used           More sophisticated medical
  to attack other life forms in the          nanorobots will be able to
  body. In essence, this would be            intervene at the cellular level,
  creating artificial antibodies, and        performing surgery within cells.
  while this is the logical
  extrapolation of the technology,          Using cytosurgical nanorobots,
  it will not happen for some time.          corrected genes could be
                                             installed in every one of the 10
 Removing or breaking down tar,             trillion tissue cells in our bodies.
  etc in lungs can be done by                We would then no longer
  removing particles of tar and              naturally age, and our bodies
  other pollutants from the surface          would again repair themselves as
  of the alveoli, and placing them           well as they did when we were
  where the natural processes of             children.
  the body can dispose of them.
  Alternatively, the unwanted
  substances could be vaporized or
  otherwise reduced to their
  component elements.                   8. Conclusion
 Removal of blood clots. They
  cause damage when they travel            As can be seen from the above, most
  to the bloodstream to a point         or all of the engineering technologies to
  where they can block the flow of      create a series of practical and effective
  blood to a vital area of the body.    nanorobots already exist. Rather than
  This can result in damage to vital    keep our eyes fixed on the far future, let
  organs in very short order. In        us start now by creating some actual
  many if not most cases, these         working devices that will allow us to
  blood clots are only detected         cure some of the most deadly ailments
  when they cause a blockage and        known, as well as advance our
  damage the organ in question,         capabilities directly, rather than as the
  often but not always the brain.       side effects of other technologies. A
  By using a nanorobot in the body      concerted development effort could have
  to break up such clots into           a working model of the nanorobot ready
  smaller pieces before they have a     within a year or two, and this would
  chance to break free and move on      certainly advance the development of
  their own, the chances of ensuing     nanotechnology.
  damage are reduced greatly.

 Nanorobotic phagocytes called
  microbivores could patrol the
  bloodstream, seeking out and
  digesting unwanted pathogens




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9. References


   1. Nanorobotics control design: A
      practical approach tutorial.
      Adiano Cavalcanti, Robert A Jr ,
      Luiz C. Koetly.
   2. REF08. Feynman, R.P. (1960)
      There's plenty of room at the
      bottom, Caltech's Engineering
      and Science, February 1960,
      pages 22-36.
   3. A Practical Nanorobot for
      treatment of various medical
      problems-Leslie Rubin Stein.
   4. Robots in the blood stream: The
      promise of nanomedicine –
      Robert Freilas.
   5. Nanorobots: Medicine of the
      future- Amit Bhargava.
   6. A.J.Menezer,V.J.Kapoor,V.K.Go
      el B.D.Cameron and J.Y.Lu
      “Within a nanometer of your
      life”,mechanical engineering
      magazine, August 2001.




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