Hi friends...In this blog i would like to post some of my paper presentations which i presented in some of the engineering colleges.....I am doing this with the hope that this would be useful for some of u ....

Medical nanorobot..........
-Replacing a surgeon



Teams around the world are working on creating the first practical medical nanorobot. Robots ranging from a millimeter in diameter to a relatively hefty two centimeters long already exist, though they are all still in the testing phase of development and haven't been used on people. We're probably several years away from seeing nanorobots enter the medical market. Today's microrobots are just prototypes that lack the ability to perform medical tasks.
In the future, nanorobots could revolutionize medicine. Doctors could treat everything from heart disease to cancer using tiny robots the size of bacteria, a scale much smaller than today's robots. Robots might work alone or in teams to eradicate disease and treat other conditions. Some believe that semiautonomous nanorobots are right around the corner -- doctors would implant robots able to patrol a human's body, reacting to any problems that pop up. Unlike acute treatment, these robots would stay in the patient's body forever.
Another potential future application of nanorobot technology is to re-engineer our bodies to become resistant to disease, increase our strength or even improve our intelligence.
Once they are created, scientists believe tiny nanorobots will be the answer to many serious conditions and diseases. Small enough to slip into the blood stream, nanorobots will treat and find disease, and restore lost tissue at the cellular level.
Nanorobotics is the technology of creating machines or robots at or close to the microscopic scale of a nanometres (10-9 metres). More specifically, nanorobotics refers to the still largely hypothetical nanotechnology engineering discipline of designing and building nanorobots. Nanorobots (nanobots, nanoids or nanites) would be typically devices ranging in size from 0.1-10 micrometers and constructed of nanoscale or molecular components. As no artificial non-biological nanorobots have so far been created, they remain a hypothetical concept at this time.
In this article we will take an in-depth look at how nanorobots work in human body, their navigation, locomotion, powering and different areas of applications.
In this we have also dealt with some interesting aspects like involvement of nanorobots in operations, treatment of deadly diseases like cancer, heart stroke.
Introduction
Just as computers revolutionized the latter half of the 20th century, the field of robotics has the potential to equally alter how we live in the 21st century. We've already seen how robots have changed the manufacturing of cars and other consumer goods by streamlining and speeding up the assembly line. We even have robotic lawn mowers and robotic pets. And robots have enabled us to see places that humans are not yet able to visit, such as other planets and the depths of the ocean.
In the coming decades, we will see robots that have artificial intelligence, coming to resemble the humans that create them. They will eventually become self-aware and conscious, and be able to do anything that a human can.
Nanorobotics is the technology of creating machines or robots at or close to the microscopic scale of a nanometres (10-9 metres).
The objective would be the rapid elimination of disease and quick, painless recovery from physical trauma. Medical nanorobots might also make possible the correction of genetic defects, and help us to live much longer, healthier lives. Somewhat more controversially, medical nanorobots could also be used to augment natural human capabilities, aiding in memory, sight, etc. Also, the safety and effectiveness of medical nanorobots will depend upon their ability to coexist within the body.
How nanorobots work?

Fig: Structure of nanorobot
Imagine going to the doctor to get treatment for a persistent fever. Instead of giving you a pill or a shot, the doctor refers you to a special medical team which implants a tiny robot into your bloodstream. The robot detects the cause of your fever, travels to the appropriate system and provides a dose of medication directly to the infected area.
Here are a few of the items you might find in a nanorobot's toolkit:
· Medicine cavity -- a hollow section inside the nanorobot might hold small doses of medicine or chemicals. The robot could release medication directly to the site of injury or infection. Nanorobots could also carry the chemicals used in chemotherapy to treat cancer directly at the site. Although the amount of medication is relatively miniscule, applying it directly to the cancerous tissue may be more effective than traditional chemotherapy, which relies on the body's circulatory system to carry the chemicals throughout the patient's body.
· Probes, knives and chisels -- to remove blockages and plaque, a nanorobot will need something to grab and break down material. They might also need a device to crush clots into very small pieces. If a partial clot breaks free and enters the bloodstream, it may cause more problems further down the circulatory system.
· Microwave emitters and ultrasonic signal generators -- to destroy cancerous cells, doctors need methods that will kill a cell without rupturing it. A ruptured cancer cell might release chemicals that could cause the cancer to spread further. By using fine-tuned microwaves or ultrasonic signals, a nanorobot could break the chemical bonds in the cancerous cell, killing it without breaking the cell wall. Alternatively, the robot could emit microwaves or ultrasonic signals in order to heat the cancerous cell enough to destroy it.
· Electrodes -- two electrodes protruding from the nanorobot could kill cancer cells by generating an electric current, heating the cell up until it dies.
· Lasers -- tiny, powerful lasers could burn away harmful material like arterial plaque, cancerous cells or blood clots. The lasers would literally vaporize the tissue.


Fig 1

Fig 2
Fig1 shows a nano-robot flowing inside a blood vessel and finds an infected cell. Fig2 shows a nano-robot which is attached on the infected cell and projects a drug to inject or destroy the cell. There are three main considerations scientists need to focus on when looking at nanorobots moving through the body -- navigation, power and how the nanorobot will move through blood vessels.
Nanorobot navigation
Navigation techniques can be divided into one of two categories: external systems and onboard systems.
External navigation systems might use a variety of different methods to pilot the nanorobot to the right location. One of these methods is to use ultrasonic signals to detect the nanorobot's location and direct it to the right destination. Doctors would beam ultrasonic signals into the patient's body. The signals would either pass through the body, reflect back to the source of the signals, or both. The nanorobot could emit pulses of ultrasonic signals, which doctors could detect using special equipment with ultrasonic sensors. Doctors could keep track of the nanorobot's location and maneuver it to the right part of the patient's body.
The second one is, using a Magnetic Resonance Imaging (MRI) device, doctors could locate and track a nanorobot by detecting its magnetic field. Because many hospitals have MRI machines, this might become the industry standard -- hospitals won't have to invest in expensive, unproven technologies.
Other methods of detecting the nanorobot include using X-rays, radio waves, microwaves or heat. Right now, our technology using these methods on nano-sized objects is limited, so it's much more likely that future systems will rely more on other methods.
Onboard systems, or internal sensors, might also play a large role in navigation. A nanorobot with chemical sensors could detect and follow the trail of specific chemicals to reach the right location. A spectroscopic sensor would allow the nanorobot to take samples of surrounding tissue, analyze them and follow a path of the right combination of chemicals.
Hard as it may be to imagine, nanorobots might include a miniature television camera. An operator at a console will be able to steer the device while watching a live video feed, navigating it through the body manually. Camera systems are fairly complex, so it might be a few years before nanotechnologists can create a reliable system that can fit inside a tiny robot.
Powering the nano-robot
A viable nanorobot has to be small and agile enough to navigate through the human circulatory system, an incredibly complex network of veins and arteries. The robot must also have the capacity to carry medication or miniature tools. Assuming the nanorobot isn't meant to stay in the patient forever, it also has to be able to make its way out of the host.
Nanorobots could get power directly from the bloodstream. A nanorobot with mounted electrodes could form a battery using the electrolytes found in blood. Another option is to create chemical reactions with blood to burn it for energy. The nanorobot would hold a small supply of chemicals that would become a fuel source when combined with blood.
A nanorobot could use the patient's body heat to create power, but there would need to be a gradient of temperatures to manage it. Power generation would be a result of the Seebeck effect. The Seebeck effect occurs when two conductors made of different metals are joined at two points that are kept at two different temperatures. The metal conductors become a thermocouple, meaning that they generate voltage when the junctures are at different temperatures. Since it's difficult to rely on temperature gradients within the body, it's unlikely we'll see many nanorobots use body heat for power.
While it might be possible to create batteries small enough to fit inside a nanorobot, they aren't generally seen as a viable power source. The problem is that batteries supply a relatively small amount of power related to their size and weight, so a very small battery would only provide a fraction of the power a nanorobot would need. A more likely candidate is a capacitor, which has a slightly better power-to-weight ratio.
Another possibility for nanorobot power is to use a nuclear power source. The thought of a tiny robot powered by nuclear energy gives some people the willies, but keep in mind the amount of material is small and, according to some experts, easy to shield [source: Rubinstein]. Still, public opinions regarding nuclear power make this possibility unlikely at best.
External power sources include systems where the nanorobot is either tethered to the outside world or is controlled without a physical tether. Tethered systems would need a wire between the nanorobot and the power source. The wire would need to be strong, but it would also need to move effortlessly through the human body without causing damage. A physical tether could supply power either by electricity or optically. Optical systems use light through fiber optics, which would then need to be converted into electricity on board the robot.
Nanorobot Locomotion
A viable nanorobot has to be small and agile enough to navigate through the human circulatory system, an incredibly complex network of veins and arteries. The robot must also have the capacity to carry medication or miniature tools. Assuming the nanorobot isn't meant to stay in the patient forever, it also has to be able to make its way out of the host.
Assuming the nanorobot isn't tethered or designed to float passively through the bloodstream, it will need a means of propulsion to get around the body. Because it may have to travel against the flow of blood, the propulsion system has to be relatively strong for its size. Another important consideration is the safety of the patient -- the system must be able to move the nanorobot around without causing damage to the host.
Some scientists are looking at the world of microscopic organisms for inspiration.
A robot only a few millimeters in length, which uses small appendages to grip and crawl through blood vessels. The scientists manipulate the arms by creating magnetic fields outside the patient's body. The magnetic fields cause the robot's arms to vibrate, pushing it further through the blood vessels. The scientists point out that because all of the energy for the nanorobot comes from an external source, there's no need for an internal power source. They hope the relatively simple design will make it easy to build even smaller robots.
Another potential way nanorobots could move around is by using a vibrating membrane. By alternately tightening and relaxing tension on a membrane, a nanorobot could generate small amounts of thrust. On the nanoscale, this thrust could be significant enough to act as a viable source of motion.
Robotic surgeons

In today's operating rooms, you'll find two or three surgeons, an anesthesiologist and several nurses, all needed for even the simplest of surgeries. Most surgeries require nearly a dozen people in the room. As with all automation, surgical robots will eventually eliminate the need for some of that personnel. Taking a glimpse into the future, surgery may require only one surgeon, an anesthesiologist and one or two nurses. In this nearly empty operating room, the doctor will sit at a computer console, either in or outside the operating room, using the surgical robot to accomplish what it once took a crowd of people to perform.
The first generation of surgical robots are already being installed in a number of operating rooms around the world. These aren't true autonomous robots that can perform surgical tasks on their own, but they are lending a mechanical helping hand to surgeons. These machines still require a human surgeon to operate them and input instructions. Remote control and voice activation are the methods by which these surgical robots are controlled.
Here are three surgical robots that have been recently developed:
· da Vinci Surgical System
· ZEUS Robotic Surgical System
· AESOP Robotic System
On July 11, 2000, the U.S. Food and Drug Administration (FDA) approved the da Vinci Surgical System, making it the first robotic system allowed to be used in American operating rooms.
In using da Vinci for gallbladder surgery, three incisions -- no larger than the diameter of a pencil -- are made in the patient's abdomen, which allows for three stainless-steel rods to be inserted. The rods are held in place by three robotic arms. One of the rods is equipped with a camera, while the other two are fitted with surgical instruments that are able to dissect and suture the tissue of the gallbladder. Unlike in conventional surgery, these instruments are not directly touched by the doctor's hands.

Fig:Da vinci surgical system

Fig: Instruments of Da vinci

ZEUS has a computer workstation, a video display, and hand controls that are used to move the table-mounted surgical instruments. While the ZEUS system has not yet been cleared for American use beyond clinical trials, German doctors have already used the system to perform coronary bypass surgery.
The ZEUS system employs the assistance of the Automated Endoscopic System for Optimal Positioning (AESOP) Robotic System. It's basically just one mechanical arm, used by the physician to position the endoscope -- a surgical camera inserted into the patient. Foot pedals or voice-activated software allow the physician to position the camera, leaving his or her hands free to continue operating on the patient.
Applications
The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery. It allows doctors the ability to operate on a patient long-distance could lower the cost of health care. In addition to cost efficiency, robotic surgery has several other advantages over conventional surgery, including enhanced precision and reduced trauma to the patient. For instance, heart bypass surgery now requires that the patient's chest be "cracked" open by way of a 1-foot (30.48-cm) long incision. However, with the da Vinci or ZEUS systems, it is possible to operate on the heart by making three small incisions in the chest, each only about 1 centimeter in diameter. Because the surgeon would make these smaller incisions instead of one long one down the length of the chest, the patient would experience less pain and less bleeding, which means a faster recovery.



Some of the most likely uses include:
· Treating arteriosclerosis: Arteriosclerosis refers to a condition where plaque builds along the walls of arteries. Nanorobots could conceivably treat the condition by cutting away the plaque, which would then enter the bloodstream.



Nanorobots may treat conditions like arteriosclerosis by physically chipping away the plaque along artery walls.
· Breaking up blood clots: Blood clots can cause complications ranging from muscle death to a stroke. Nanorobots could travel to a clot and break it up. This application is one of the most dangerous uses for nanorobots -- the robot must be able to remove the blockage without losing small pieces in the bloodstream, which could then travel elsewhere in the body and cause more problems. The robot must also be small enough so that it doesn't block the flow of blood itself.
· Fighting cancer: Doctors hope to use nanorobots to treat cancer patients. The robots could either attack tumors directly using lasers, microwaves or ultrasonic signals or they could be part of a chemotherapy treatment, delivering medication directly to the cancer site. Doctors believe that by delivering small but precise doses of medication to the patient, side effects will be minimized without a loss in the medication's effectiveness.
· Helping the body clot: One particular kind of nanorobot is the clottocyte, or artificial platelet. The clottocyte carries a small mesh net that dissolves into a sticky membrane upon contact with blood plasma. Clotting could be up to 1,000 times faster than the body's natural clotting mechanism. Doctors could use clottocytes to treat hemophiliacs or patients with serious open wounds.
· Parasite Removal: Nanorobots could wage micro-war on bacteria and small parasitic organisms inside a patient. It might take several nanorobots working together to destroy all the parasites.
· Gout: Gout is a condition where the kidneys lose the ability to remove waste from the breakdown of fats from the bloodstream. This waste sometimes crystallizes at points near joints like the knees and ankles. People who suffer from gout experience intense pain at these joints. A nanorobot could break up the crystalline structures at the joints, providing relief from the symptoms, though it wouldn't be able to reverse the condition permanently.
· Breaking up kidney stones: Kidney stones can be intensely painful -- the larger the stone the more difficult it is to pass. Doctors break up large kidney stones using ultrasonic frequencies, but it's not always effective. A nanorobot could break up a kidney stones using a small laser.
Nanorobots might carry small ultrasonic signal generators to deliver frequencies directly to kidney stones.
· Cleaning wounds: Nanorobots could help remove debris from wounds, decreasing the likelihood of infection. They would be particularly useful in cases of puncture wounds, where it might be difficult to treat using more conventional methods.

Nanorobots can also replace damaged cell.


Conclusion
Medical Nanorobots, when fully developed, will radically change the scope of what is possible in medical science. Medical Nanorobots have the potential to quickly eliminate toxins or cancer cells, repair damaged biological structures, and restore and maintain the body in a state of youthful health. It is likely that the first medical nanorobots may be buildable 10-20 years from today using an advanced molecular manufacturing technology. Medical nanorobots will have posess onboard sensors, molecular pumps and valves, computers, energy supplies, and components for communication, manipulation, and navigation.