Like primitive engineers faced with advanced technology, medicine must ‘catch up' with the technology level of the human body before it can become really effective. Since the human body is basically an extremely complex system of interacting molecules (i.e., a molecular machine), the technology required to truly understand and repair the body is molecular machine technology. A natural consequence of  this level of technology will be the ability to analyze and repair the human body as completely and effectively as we can repair any conventional machine today

                NanotechnologyisResearch and technology development at the atomic, molecular and macromolecular levels in the length scale of approximately 1 -100 nanometer range, to provide a fundamental understanding of phenomena and materials at the nanoscale and to create and use structures, devices and systems that have novel properties and functions because of their small and/or intermediate size.”                                      

This paper will describe a micro/nano scale medical robot that is within the range of current engineering technology. It is intended for the treatment and/or elimination                 of medical problems where accumulation of undesired organic substances interferes with normal bodily function.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         NANOMEDICNE: 

     It is the application of nanotechnology (engineering of tiny machines) to the prevention and treatment of disease in the human bodys. More specifically, it is the use of engineered nanodevices and nanostructuresto monitor, repair, construct and control the human biological system on a molecular level. The most elementary of nanomedical devices will be used in the diagnosis of illnesses. A more advanced use of nanotechnology might involve implanted devices to dispense drugs or hormones as needed in people with chronic imbalance or deficiency states. Lastly, the most advanced nanomedicine involves the use of Nanorobots as miniature surgeons. Such machines might repair damaged cells, or get inside cells and replace or assist damaged intracellular structures. At the extreme, nanomachines might replicate themselves, or correct genetic deficiencies by altering or replacing DNA (deoxyribonucleic acid) molecules.

Introduce the device into the body:

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 have already made the decision to gain access via the circulatory system.

The first is that the size of the nanomachine determines the minimum size of the blood vessel that it can traverse. We want to avoid damaging the walls of whatever blood vessel the device is in, we also do not want to block it much, which would either cause a clot to form, or just slow or stop the blood flow. What this means is that 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 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 we have to get it into the body without being too destructive in the first place. This requires that we gain access to a large diameter artery that can be traversed easily to gain access to most areasof the body in minimal time. The obvious candidate is the femoral artery in the leg. This is in fact the normal access point to the circulatory system for operations that require access to the bloodstream for catheters, dye injections, etc., so it will suit our purposes.

Move the device around the body:

We start with a basic assumption: that we will use the circulatory system to allow our device to move about. We must then consider two possibilities: (a) carried to the site of operations,(b) to  be propelled

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 . 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. In the case of tumors, there is very often damage to the circulatory system that would prevent our device from passively navigating to the site. In the case of blood clots, of course, the flow of bloodis dammed and thus our device would not be carried to the site without the capability for active movement. Another problem with this method is that it would be difficult to remain at the site without some means of maintaining position, either by means of an anchoring technique, or by actively moving against the current.

There are a number of means available for active propulsion of our device.


An  electric motor that fit within a cube 1/64th of an inch on a side is used  . This is probably smaller than we would need for our preliminary microrobot. One or several of these motors could be used to power propellers that would push (or pull) the microrobot through the bloodstream. We would want to use a shrouded blade design so as to avoid damage to the surrounding tissues (and to the propellers) during the inevitable collisions


 we are using some sort of vibrating cilia

similar to those of a paramecium) to propel the device. A variation of this method would be to use a fin-shaped appendage. While this may have its attractions at the molecular level of operation,

3.Crawl along surface:

Rather than have the device float in the blood, or in various fluids, the device could move along the walls of the circulatory system by means of appendages with specially designed tips, allowing for a firm grip without excessive damage to the tissue. It must be able to do this despite surges in the flow of blood caused by the beating of the heart, and do it without tearing through a blood vessel or constantly being torn free and swept away.

       along the wall of vessel

For any of these techniques to be practical, they must each meet certain requirements:

The device must be able to move at a practical speed against the flow of blood.

The device must be able to move when blood is pooling rather than flowing steadily.

The device must be able to move in surges, so as to be able to get through the heart without being stuck, in the case ofemergencies.

The device must either be able to react to changes in blood flow rate so as to maintain position, or somehow anchor itself to the body so as to remain unmoving while operating.

Movement of  the device :

The next problem to consider is exactly how to detect the problem tissue that must be treated. We need two types of sensors. Long-range sensors will be used to allow us to navigate to the site of the unwanted tissue. We must be able to locate a tumor, blood clot or deposit of arterial plaque closely enough so that the use of short-range sensors is practical. These would be used during actual operations, to allow the device to distinguish between healthy and

unwanted tissue.. Another important use for sensors is to be able to locate the position of the microrobot in the body. First we will examine the various possibilities for external sensors. These will be at least partially external to the microrobot, and their major purpose will be twofold. The first is to determine the location of the operations site; that is, the location of the clot, tumor or whatever is the unwanted tissue. The second purpose is to gain a rough idea of where the microrobot is in relation to that tissue. This information will be used to navigate close enough to the operations site that short-range sensors will be useful


This technique can be used in either the active or the passive mode. In the active mode, an ultrasonic signal is beamed into the body, and either reflected back, received on the other side of the body, or a combination of both. The received signal is processed to obtain information about the material through which it has passed.

 In the passive mode, an ultrasonic signal of a very specific pattern is generated by the microrobot. By means of signal processing techniques, this signal can be tracked with great accuracy through the body, giving the precise location of the microrobot at any time. The signal can either be continuous or pulsed to save power, with the pulse rate increasing or being switched to continuous if necessary for more detailed position information.


This technique involves the application of a powerful magnetic field to the body, and subsequent analysis of the way in which atoms within the body react to the field It usually requires a prolonged period to obtain useful results, often several hours, and thus is not suited to real-time applications. While the performance can be increased greatly, the resolution is inherently low due to the difficulty of switching large magnetic fields quickly, and thus, while it may be suited in some cases to the original diagnosis, it is of only very limited use to us at present.


X-rays as a technique have their good points and bad points. On the plus side, they are powerful enough to be able to pass through tissue, and show density changes in that tissue. This makes them very useful for locating cracks and breaks in hard, dense tissue such as bones and teeth. On the other hand, they go through soft tissue so much


bile Xray

more easily that an X-ray scan designed to show breaks in bone goes right through soft tissue without showing much detail. On the other hand, a scan designed for soft tissue can’t get through if there is any bone blocking the path of the x-rays.

Control the device:

 we consider the case of internal sensors. When we say internal sensors, we mean sensors that are an integral part of the microrobot and are used by it to make the final approach to the operation site and analyze the results of its operations. These sensors will be of two types. The first type will be used to do the final navigation. When the device is within a short distance of the operation site, these sensors will be used to help it find the rest of the path, beyond what the external sensors can do. The second type of sensor will be used during the actual operation, to guide the microrobot to the tissue that should be removed and away from tissue that should not be removed.


Chemical sensors can be used to detect trace chemicals in the bloodstream and use the relative concentrations of those chemicals to determine the path to take to reach the unwanted tissue. This would require several sensors so as to be able to establish a chemical gradient, the alternative would be to try every path, and retrace a path when the blood chemicals diminish. While it is not difficult to create a solid-state sensor for a given chemical, the difficulty increases greatly when the number of chemicals that must be analyzed increases. Consequently, we would probably need a series of microrobots, one for each chemical, or at least a set of replaceable sensor modules


This would involve taking continuous small samples of the surrounding tissue and analyzing them for the appropriate chemicals. This could be done either with a high-powered laser diode or by means of an electrical arc to vaporize small amounts of tissue. The laser diode is more practical due to the difficulty of striking an arc in a liquid medium and also due to the side effects possible when sampling near nerve tissue. The diode could be pulsed at regular intervals, with an internal capacitor charging constantly so as to provide more power to the laser diode than the steady output of our power source.

(3).TV camera:

This method involves us having a TV camera in the device and transmitting its picture outside the body to a remote control station, allowing the people operating the device to steer it. One disadvantage of this technique is the relatively high complexity of the sensors. On the other hand, solid-state television sensors are an extremely well developed technology, and it should not be difficult to further develop it to the level needed. This could be combined with the laser diode at low power

Means of treatment:

The treatment for each of the medical problems is the same in general; we must remove the tissue or substance from the body. This can be done in one of several ways. We can break up the clump of substance and rely on the body’s normal processes to eliminate it. Alternately, we can destroy the substance before allowing the body to eliminate the results. We can use the microrobot to physically remove the unwanted tissue. We can also use the microrobot to enhance other efforts being performed, and increase their effectiveness.

(1).Physical removal:

This method can be effective in the treatment of arteriosclerosis. In this case, a blade, probe or edge of some sort can be used to physically separate deposits of plaque from the artery walls. The bloodstream would carry these deposits away, to be eliminated by the normal mechanisms of the body.

In the case of blood clots, it is possible that the action of physically attacking the clot could cause it to break away in large chunks, some of which could subsequently cause blockages in the blood flow.. We can set up some mechanism to catch these blood clots and further break them up,

In the case of tumors, the problem is more serious. The act of physically shredding or even just breaking loose clumps of cells can result in the cancer metastasizing throughout the body. One possible solution is to filter the cancerous cells out of the blood immediately downstream of the tumor. Even if it is possible to distinguish cancerous cells from normal cells by filtering, this would not prevent the spread of tumor causing chemicals released by the ruptured cells.

(2).Physical trauma:

Another way of dealing with the unwanted tissues is by destroying them in situ. This would avoid damaging the cancerous cells and releasing chemicals into the bloodstream. In order to do this effectively, we need a means of destroying the cell without rupturing the cell wall until after it is safe. We shall consider a number of methods

(a)Resonant microwaves/Ultrasonics:

Rather than merely apply microwave/infrared or ultrasonic energy at random frequencies, the frequency of the energy could be applied at the specific frequencies needed to disrupt specific chemical bonds. This would allow us to make sure that the tumor producing chemicals created by cancerous cells wouldbe largely destroyed, with the remaining amounts, if any, disposed of by the body’s natural defenses.


The use of heat to destroy cancerous tumors would seem to be a reasonable approach to take. There are a number of ways in which we can apply heat, each with advantages and disadvantages of their own. While the general technique is to apply relatively low levels of heat for prolonged periods of time, we can apply much higher levels for shorter periods of time to get the same effect.

( c )Microwave:

Microwave radiation is directed at the cancerous cells, raising their temperature for a period of time, causing the death of the cells in question. This is normally done by raising the temperature of the cells to just enough above body temperature to kill them after many minutes of exposure.


 An ultrasonic signal, which can be generated by a piezoelectric membrane or any other rapidly vibrating object, is directed at, and absorbed by, the cells being treated. This energy is converted to heat, raising the temperature of the cells and killing.

(e)Power from the bloodstream:

There are three possibilities for this scenario. In the first case, the microrobot would have electrodes mounted on its outer casing that would combine with the electrolytes in the blood to form a battery. This would result in a low voltage, but it would last until the electrodes were used up. The disadvantage of this method is that in the case of a clot or arteriosclerosis, there might not be enough blood flow to sustain the required

Power to NanoRobot:

In this case, the power would be transmitted to the microrobot from outside the body. This can be done in a number of different ways, but it boils down to two possibilities. The first is to transmit the power by means of a physical connection, and the second, of course, is to transmit it without a physical connection.

(a)Physical connection

In the first case, we would need some sort of wire or cable to carry power between the microrobot and the outside power source. Problems faced are the first, of course, is that the wire needs to be able to reach inside the body to where the microrobot is. This means that it must be thin enough to fit down every blood vessel that the microrobot can enter.

(b)No physical connection:

we are transmitting power to the microrobot without the use of wires or any sort of physical means to transfer the power.


2.Induced magnetic

Means of recovery from the body:

Given sufficiently accurate control of the nanomachine, or a tether, this is not a problem; 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 nanomachine out of the bloodstream. This will reduce the possibilities for difficulties, and also cause less wear and tear on the nanomachine. Of course, either scenario is a possibility, depending on where the actual operation site is. Another possibility is to have the nanomachine anchor itself to a blood vessel that is easily accessible from outside, and perform a small surgical operation to remove it.

Application of nanorobots :


We must be able to treat tumors; that is to say, cells grouped in a clumped mass. While the technique may eventually be used to treat small numbers of cells in                                    lung tumor

the bloodstream,,. The specified goal is to be able to destroy tumorous tissue in such a way as to minimize the risk of causing or allowing a recurrence of the growth in the body. The technique is intended to be able to treat tumors that cannot be accessed via conventional surgery, such as deep brain tumors.


 This is caused by fatty deposits on the walls of arteries. The device should be able to remove these deposits from the   artery walls. This will allow for both improving the flexibility of the walls of the arteries and improving the blood flow through them. In view of the years it takes to accumulate these deposits, simply removing them from the artery walls and leaving them in the bloodstream should allow the body’s natural processes to remove the overwhelming preponderance of material.

3.Blood clots:

 The cause damage when they travel to the bloodstream to a point where they can block the flow of blood to a vital area of the body. This can result in damage to vital organs in very short order. In many if not most cases, these

              Blood clot

blood clots are only detected when they cause a blockage and damage the organ in question, often but not always the brain. By using a microrobot in the body to break up such clots into smaller pieces before they have a chance to break free and move on their own

 4.Kidney stones

By introducing a microrobot into the urethra in a manner similar to that of inserting a catheter, direct access to the kidney stones can be obtained, and they can be broken up directly. This can be done either by means of ultrasonics directly applied, or by the use of a laser or other means of applying intense local heat to cause the stones to break up.

5.Liver stones

Liver stones accumulate in the bile duct. Microrobots of the above type can be introduced into the bile duct and used to

tones Inside Liver Bile Ducts

 break up the liver stones as well. By continuing on up the bile duct into the liver, they can clear away accumulated deposits of unwanted minerals and other substances as well.

6.Burn and wound debriding:

The microrobots can also be used to clean wounds and burns. Their size allows them to be very useful for removing dirt and foreign particles from incised and punctured wounds, as well as from burns. They can be used to do a more complete and less traumatic job than conventional techniques. 

7.Remove or break down tar, etc in lungs:

They could be very useful for the treatment of dirty lungs. This could be done by removing particles of tar and other pollutants from the surface of the alveoli, and placing them where the natural processes of the body can dispose of them. This would require a microrobot capable of moving within the lungs, on alveolar surfaces as well as

        ver the mucus layer and over the cilia within the lungs.


1.Speed of Medical Treatment:Doctors may be surprised by the incredible quickness of nanorobotic action when compared to the speeds available from fibroblasts or leukocytes. Biological cilia beat at ~30 Hz while mechanical nanocilia may cycle up to ~20 MHz, though practical power restrictions and other considerations may limit them to the ~10 KHz range for most of the time.

2. Non-degradation of Treatment Agents:

Diagnostic and therapeutic agents constructed of biomaterials generally are biodegradable in vivo. However, suitably designed nanorobotic agents constructed of nonbiological materials are not biodegradable.

3.Control of Nanomedical Treatment:A digital biocomputer, which is possible in theory, has slower clock cycles, less capacious memory per unit volume, and longer data access time and poorer control

4.Faster and More Precise Diagnosis: The analytic function of medical diagnosis requires rapid communication between the injected devices and the attending physician. Nanomachines, with their more diverse set of input-output mechanisms, can out message the results of in vivo reconnaissance or testing literally in seconds

5. Verification of Progress and Treatment: Using a variety of communication modalities, nanorobots can report back to the attending physician, with digital precision, a summary of diagnostically- or therapeutically-relevant data describing exactly what was found, and what was done, and what problems were encountered, in every cell visited

6.Minimum Side Effects: Mechanical nanorobots may be targeted with virtually 100% accuracy to specific organs, tissues, or even individual cellular addresses within the human body . Such nanorobots should have few if any side effects, and will remain safe even in large dosages because their actions can be digitally self-regulated using rigorous control protocols.



Nanomedicine will eliminate virtually all common diseases of the 20th century, virtually all medical pain and suffering, and allow the extension of human capabilitiesemdashmost especially our mental abilities.

A nanostructured data storage device about the size of a human liver cell implanted in the brain could store a large amount of data and provides extremely rapid access to this information. But perhaps the most important long-term benefit to human society as a whole could be the dawning of a new era of peace. We could hope that people who are independently well fed, well-clothed, well-housed, smart, well educated, healthy and happy will have little motivation to make war. Human beings who have a reasonable prospect of living many "normal" lifetimes will learn patience from experience, and will be extremely unlikely to risk those "many lifetimes" for any but the most compelling of reasons.

                           Finally, and perhaps most importantly, no actual working nanorobot has yet been built. Many theoretical designs have been proposed that look good on paper, but these preliminary designs could change significantly after the necessary research, development and testing has been completed.








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Wed, 11/05/2011 - 14:58