23-07-2012, 04:47 PM
Nano robots in medical applied fields
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Abstract
Nano robots, nanomachines, and other nanosystems discussed in this paper are objects with overall sizes on the order of a few micrometers or less in all three spatial directions, and which are assemblies of nanoscopic components with individual dimensions 1– 100 nm. Medical nanodevices travelling in the human body for therapeutic purposes have captured the public’s imagination at least since the times of the movie Fantastic Voyage (Twentieth Century Fox, winner of the 1966 Oscar for best visual effects). Nan robotics is the study of robotics at the nanometer scale, and includes robots that are nanoscale in size and large robots capable of manipulating objects that have dimensions in the nanoscale range with nanometer resolution. Nan robotic manipulation is an enabling technology for NEMS (NanoElectroMechanical Systems) and promising for nanorobots. NEMS with novel nanoscale materials and structures will enable many new nanosensors and nanoactuators. The joint use of nanoelectronics, photolithography, and new biomaterials, have enabled the required manufacturing technology towards nanorobots for common medical applications, such as surgical instrumentation, diagnosis and drug delivery. Nan robots have various usages and plays a different role depending on their applications.
REVIEW OF LITERATURE
Nanorobotics encompasses the design, fabrication, and programming of robots with overall dimensions below a few micrometers, and the programmable assembly of nanoscale objects. Nanorobots are quintessential nanoelectromechanical systems (NEMS) and raise all theimportant issues that must be addressed in NEMS design: sensing, actuation, control, communications, power, and interfacing across spatial scales and between the organic/inorganic and biotic/abiotic realms. Nanorobots are expected to have revolutionary applications in such areas as environmental monitoring and health care.
KEY TECHNIQUES FOR NANOROBOTS
Nanorobotics is a multidiscipline consists of
nanotechnology, biology and robotics, it focus on the
construction, assembly, control of the nanorobot and
operation of molecular scale objects and its most
prospective and application is in nanomedicine.
Nanomedicine-oriented nanorobot works in human body
environment, so there are additional requirements in size,
reliability, efficiency, security and biocompatibility,
accesses capillary vessel and cells.
ACTUATORS
A set of fullerene structures were presented for
nanoactuators. The use of Carbon Nanotubes (CNTs) as
conductive structures permits electrostatically driven
motions providing forces necessary for nanomanipulation.
For a medical nanorobot, the use of CMOS as an actuator
based on biological patterns and CNTs is adopted in our
architecture as a natural choice. Ion channels can interface
electrochemical signals using sodium for the energy
generation which is necessary for mechanical actuators
operation [31]. Embedded actuators are programmed to
perform different manipulations, enabling the nanorobot a
direct active interaction with the bloodstream patterns and
the molecular parameters inside the body.
PROPULSION
Swimming or flying in fluids seems more attractive than walking or crawling on a surface, since most objects likely to be encountered on a surface are large and difficult to superate by a nanoscale walking or crawling machine. Bacteria are good models for nanorobots because they have sizes on the order of a few micrometers, which are likely to be comparable to those of future nanorobots, and move in fluids. In nature, objects with dimensions on the order of a few nanometers, such as the molecules used for chemical signaling, are not self-propelled and rely on diffusion. In fact, it appears that there are no self-propelled organisms with sizes below 600 nm. Attempting to propel and steer a smaller organism is ineffective because of the numerous collisions that will change its course unpredictably.
COMMUNICATION
Communication among nanorobots by means of waves, be they acoustic, electrical, or optical, is likely to be difficult because of the small antenna sizes. If we look at what nature does, we find that bees communicate directly by dancing; ants communicate by releasing chemicals (pheromones) that change the environment (this is called stigmergy in the robotics field); and bacteria also release chemicals, for example, to assess the number of similar bacteria near them. This bacterial behavior is called quorum sensing and uses a very simple strategy. If each bacterium releases a fixed amount of a given chemical, it suffices to measure the concentration of the chemical to find how many bacteria are in a neighborhood. The vast majority of the communications between small objects such as cells and subcellular structures is done chemically, by using molecular recognition. As we noted above, in Section II-B, chemical signaling requires contact and poses interesting challenges for the design of robotic.
NANOROBOT IN TISSUE REPAIR AND REPLACEMENT
Nanorobot offers sensing technologies that provide more accurate and timely medical information for diagnosing disease, and miniature devices that can administer treatment automatically if’ required. Complementary microprocessors and miniature devices can be incorporated with sensors to diagnose disease, transmit information and administer treatment automatically if required. For example, a class of drug delivery systems based on nanotechnology is in the area of nanorobots that carry drugs to their destination sites (cells and tissues) and also have functional properties. Certain nanostructures can be controlled to link with a drug, a targeting molecule, and an imaging agent, then attract specific cells and release their payload when required.Another type of drug delivery systems is materials (liposomes and polymers) that encapsulate drugs to protect them during transit in the body. The materials form capsules around the drugs and permit timed drug release to occur as the drug diffuses through the encapsulation material.
CONCLUSION
These are some of the few applications of nanorobotics in the field of medicine. All these developments in the field of nanomedicine aims towards a future which brings about simplicity, quick and accurate diagnosis of diseases. Further improvements can be made in this domain to such an extent that diagnosis of simple illnesses is not painful. Nanotechnology as a diagnostic and treatment tool for patients with cancer and diabetes showed how actual developments in new manufacturing technologies are enabling innovative works which may help in constructing and employing nanorobots most effectively for biomedical problems. 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.