NANOROBOTS A FUTURE DEVICE FOR DIAGNOSIS AND TREATMENT

This article focusses on the application of the nanorobots in diagnosis and treatment of some of the diseases like cancer, heart diseases, diabetes, gout etc. Nanorobots are controllable machines at the nanometer or molecular scale that are composed of nano scale components. With the modern scientific capabilities, it has become possible to attempt the creation of nanorobotic devices and interface them with the macro world for control. These devices are also a helpful tool in the drug delivery, which is a very important aspect of medical treatment. Nanorobots are capable of performing task like actuating, sensing, signalling, information processing and intelligence at the nanoscale. The most recent application of these devices are, the brain targeted delivery of drugs, glucose monitoring in diabetes patients, bone reconstruction, cancer treatment, removal of blood clots, nerve regeneration and protein and peptide drug delivery system. Thus they play a vital role in the field of biomedicine especially in the treatment of cancer, cerebral aneurysm, kidney stones removal and some other treatments that have greatest aid to save human lives. This review guides to the recent research on nanorobots in the bio medical applications.

the operator"s perception by approaching more or less a state of "full immersion" or "telepresence". Fabrication and controls of the nanorobots are the main challenges in the development of nanorobots or nano machine components. Such devices will operate in microenvironments whose physical properties differ from those encountered by conventional parts. Nanorobotics is a field which calls for collaborative efforts between physicists, chemists, biologists, computer scientists, engineers and other specialists to work towards this common objective. Currently this field is still evolving, but several substantial steps have been taken by great researchers all over the world and are contributing to this ever challenging and exciting field. [7] Ideal characteristics of nanorobots  Nanorobots must have size in between 0.5 to 3 microns large with 1-100 nm parts.
 Nanorobots of larger size than the above will block capillary flow.
 It will prevent itself, from being attacked by the immune system by having a passive, diamond exterior.
 It will communicate with the doctor by encoding messages to acoustic signals at carrier wave frequencies of 1-100 MHz.
 It might produce multiple copies of it to replace worn-out units, a process called selfreplication. [6] Types of nanorobots Some researchers classify nanorobots in drug delivery and therapeutics according to the their applications, which are described below, 1) Pharmacyte: It is a medical nanorobot having a size of 1-2 μm able to carrying up 1 μm3 a given drug in the tanks. They are controlled using mechanical systems for sorting pumps. They are provided with a molecular markers or chemotactic sensors that guarantee full targeting accuracy. Glucose and oxygen extracted from the local environments such as blood, intestinal fluid and cytosol are the on board power supply.
After the nanorobot completing tasks they can be removed or recovered by centrifuge nanapheresis. 2) Diagnosis and Imaging: They have microchips that are overlaid with human molecules.
The chip is projected to send an electrical signal when the molecules detect a disease.
Gives an example of special sensor nanobots that can be introduced into the blood under the skin where they verify blood contents and notify of any possible diseases. They can also be used to monitor the sugar level in the blood. Advantages are the low price to produce and easily to manipulate. [9] Fig: Nanorobots in blood vessel for Diagnosis and Imaging.

3) Respirocyte:
It is an Artificial Oxygen Carrier nanorobot which is about an artificial red blood cell. The power is obtained by endogenous serum glucose. This artificial cell is able to give 236 times more oxygen to the tissues per unit volume than RBCs (Red blood cells) and to administer acidity. [10] Figure: Respirocytes.

5) Clottocytes:
This is a type of nanorobot, with a unique biological capability: "instant" hemostasis using clottocytes, or artificial mechanical platelets. It is known that platelets are roughly spheroidal nucleus-free blood cells measuring approximately 2 μm in diameter. Platelets join at a place of bleeding. There they are activated, becoming tacky and lumping together to form a tampon that aid stamp the blood vessel and stop the bleeding. They also delivery substances that help promote coagulating. [10] 6) Chromallocyte: The Chromallocyte would replace entire chromosomes in individual cells thus reversing the effects of genetic disease and other accumulated damage to our genes, preventing aging. Inside a cell, repair machine will first size up the situation by examining the cell's contents and activity, and then take action by working along molecule-by-molecule and structure-by structure; repair machines will be able to repair the whole cell.

Advantages of nanorobots
 Use of nanorobot drug delivery systems with increased bioavailability;  Targeted therapy such as only malignant cells treated;  Reach remote areas in human anatomy not operatable at the surgeon"s operating table;  As drug molecules are carried by nanorobots and released where needed the advantages of large interfacial area during mass transfer can be realized;  Non-invasive technique;  Computer controlled operation with nobs to fine tune the amount, frequency, time of release;  Better accuracy;  Drug inactive in areas where therapy not needed minimizing undesired side effects. [13]  Small size-The upper limit of the size of nanorobot is 3 micron so that it can easily flow in the body without blocking the capillary flow.
 Cost effective (if mass produced) -Manufacturing by batch processing reduces the cost even if the initial cost of development is high.
 Less post treatment care -As it is minimally invasive technique, therefore less post treatment care is required. [11] Structure and design of nanorobots  Probes, knives and chisels: These are used to remove plaque and blockages these probes, knives and chisels are used. These parts help Nanorobot to grab and break down the material. Also they might 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.  Power supply for nanorobots: The major requirement for the nanorobot is, of course, power. The nanorobots require power to allow it to perform all of its required operations.
There are two possible ways.
o The first is to obtain the power from a source within the body, either by having a selfcontained power supply, or by getting power from the bloodstream.
o The second possibility is to have power supplied from a source external to the body. Properly configured dentifrobots can identify and destroy pathogenic bacteria that exist in the plaque and elsewhere. These invisibly small dentifrobots are purely mechanical devices that safely deactivate themselves when swallowed. [1] Fig: Dentifrobots.

Nanoanesthesia:
Oral anaesthesia is the most common procedures in dental practice, for that dental professionals will instil a colloidal suspension containing millions of active analgesic micron-sized dental nanorobot 'particles' on the patient's gingiva. After contacting the surface of the crown or mucosa, the ambulating nanorobots reach the dentin by migrating into the gingival sulcus and passing painlessly through the lamina propria or the 1 to 3-micron thick layer of loose tissue at the cement identinal junction.
On reaching dentin, the nanorobots enter dentinal tubules holes that are 1 to 4 microns in diameter and proceed toward the pulp, guided by a combination of chemical gradients, complications. [15] Some other applications in the dentistry are tooth repair; Tooth repositioning, Dentin hypersensitivity etc.

Application of nano robots in cancer treatment
The patient will have more chances for treating from cancer if it diagnosed earlier. Considering the properties of nanorobots to navigate as blood borne devices, they can help on such extremely important aspects of cancer therapy. Nanorobots with embedded chemical biosensors can be used to perform detection of tumour cells in early stages of development inside the patient"s body. Integrated nano sensors can be utilized for such a task in order to find intensity of Ecadherin signals. Therefore a hardware architecture based on nano bioelectronics is described for the application of nanorobots for cancer therapy. [10] The scientists have genetically modified salmonella bacteria that are drawn to tumors by chemicals secreted by cancers cells. The bacteria carry microscopic robots, about 3 micrometers in size that automatically release capsules filled with drugs when the bacteria reach the tumor. By delivering drugs directly to the tumor, the nanorobot, which the team named bacteriobot, attacks the tumor while leaving healthy cells alone, sparing the patient from the side effects of chemotherapy. [6,9] www.wjpr.net

An Artificial Oxygen Carrier Nanorobot
"Respirocyte" is the artificial mechanical red cell, an imaginary nanorobot which floats along in the blood stream. It is essentially a small pressure tank that can be pumped full of oxygen (O 2 ) and carbon dioxide (CO 2 ) molecules. Later on, these gases can be released from the small tank in a controlled manner. These atoms are mostly carbon atoms arranged as diamond in a porous lattice structure inside the spherical shell.
Outside of each device there are gas concentration sensors. When the nanorobot passes through the lung capillaries, O 2 partial pressure is high and CO 2 partial pressure is low, so the onboard computer tells the sorting rotors to load the tanks with oxygen and to dump the CO 2 .
When CO 2 partial pressure is relatively high and O 2 partial pressure relatively low the onboard computer commands the sorting rotors to release O 2 and to absorb CO 2 . Respirocytes simulate the action of the natural hemoglobin-filled red blood cells, but they can deliver 236 times more oxygen per unit volume than a natural red cell.

As Artificial Phagocyte (Microbivore)
Microbivore is an artificial mechanical phagocyte of microscopic size whose primary function is to destroy microbiological pathogens found in the human bloodstream, using the "digest and discharge" protocol. The chief function of microbivore is to wipe out microbiological pathogens found in the human bloodstream, using the "digest and discharge" procedure. Microbivores upon given intravenously (I.V) would achieve complete clearance of the most severe septicemic infections in hours or less, far better than the weeks or months needed for antibiotic-assisted natural phagocytic defenses. [6] Heart-attack prevention Nanorobots can also be used to prevent heart-attacks. Heart-attacks are caused by fat deposits blocking the blood vessels. Nanorobots can be made for removing these fat deposits. The nanorobots remove the yellow fat deposits on the inner side of blood vessels. This will allow for both improving the flexibility of the walls of the arteries and improving the blood flow through them. [18] From this hypothesis, such technology will help for delivery of drugs like lipid lowering substances such as lovastatin, simvastatin etc. These drug molecules will enter with nanorobots and give delivery at the site of action. [2,8] www.wjpr.net

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. [14]

Nanorobots in Kidney disease
Nanorobots are used to break the kidney stones with the help of ultrasonic shocks. Kidney stones are painful and a large stone does not pass out in urine. Sometimes doctor break this stones by ultrasonic frequency but, these are not effective in always. Nanorobots break up these kidney stones by using small laser and these smaller pieces are passing out in urine outside the body. [2] CONCLUSION Considering the severe side effects of the existing therapies like radiation and chemotherapy the nanorobots from the field of nanomedicine can be an innovative, supportive and optimistic machine technology for patients in the treatment and diagnosis of life threatening diseases. In future, the main emphasis in medicine will shift from medical science to medical engineering, where nanorobotic technology will be the revolution. Nanorobots applied to medicine hold a wealth of promise from eradicating disease to reversing the aging process (wrinkles, loss of bone mass and age-related conditions are all treatable at the cellular level); nanorobots are also candidates for industrial applications. They will provide personalised treatments with improved efficacy and reduced side effects that are not available today.