Nanorobotics is an emerging field that deals with the controlled manipulation of objects with nanometer-scale dimensions. Typically, an atom has a power of few Armstrong (1A=0.1nm=10-10m), a molecule’s size is a few nm, and clusters or nanoplastics formed by hundreds or thousands of atoms have sizes of tens of nm. Therefore, Nanorobotics is concerned with interactions with atomic- and molecular-sized objects- and is sometimes called Molecular Robotics.
Molecular Robotics falls within the purview of Nanotechnology, which is the study of phenomena and structures with characteristic dimensions in the nanometer range. The birth of nanotechnology is usually associated with a talk by Nobel-prize winner Richard Feynman entitled “There is plenty of room at the bottom”. Nanotechnology has the potential for major scientific and practical breakthroughs.
There are two main approaches for building useful devices from nanoscale components. The first is based on self-assembly, and is a natural evolution of traditional chemistry and bulk processing. The other is based on controlled positioning of nanoscale objects, direct application of forces, electric fields, and so on. The self –assembly approach is being pursued at many laboratories. Despite all the current activity, self-assembly have several limitations because the structures produced tend to be highly symmetric, and the most versatile self assembled systems are organic and therefore generally lack robustness. The second approach involves Nan manipulation, and is being studied by a small number of researchers, who are focusing on techniques based on Scanning Probe Microscopy.
As science and engineering evolve over time we, as a human race, begin to see that the separation between science fiction and science dwindles into an unclear, barely noticeable barrier. It is believed by many that science fiction can no longer be classified as an improbable world because technology allows us to create what once was thought to be fantasy. An example of this leap from dreams to reality is the leap humanity took from Frankenstein to Dolly. Science took a monster from Mary Shelley’s imagination and engineered an animal capable of everything a naturally bred sheep can do.
To continue this process of almost unimaginable feasts, humanity now has its sights set on controlling outcomes on the sub-molecular level. Creating nanobots, nanoids, nanites, or nanonites to detect early stages of cancer prior to any detection of typical symptoms is only the beginning stages of these possibilities. Further development can lead our imagination to the creation of nano-scaled devices that can easily detect radiation without having to endanger human lives. Furthermore, if science and engineering prove to be able to perfectly control Nanorobotics then perhaps all humans will one day exist with nanobots existing within.
Prior to explaining the possibilities and the direction of this technology we must first understand what nanotechnology is and the difficulty that arises in this field. First off, nanotechnology is described as the “field that deals with the controlled manipulation of objects with nanometer-scale dimensions”. To put things into perspective an atom is about an Armstrong in diameter (1x10-10m) while the components of a nanobots only have diameters of 1x10-9m.
Nanotechnology can best be defined as a description of activities at the level of atoms and molecules that have applications in the real world. A nanometer is a billionth of a meter, that is, about 1/80,000 of the diameter of a human hair, or 10 times the diameter of a hydrogen atom. The size-related challenge is the ability to measure, manipulate, and assemble matter with features on the scale of 1 to 100 nm. In order to achieve cost-effectiveness in nanotechnology it will be necessary to automate molecular manufacturing. The engineering of molecular products needs to be carried out by robotic devices, which have been termed as nanorobots. A nanorobot is essentially a controllable machine at the nanometer or molecular scale that is composed of nanoscale components. The field of Nanorobotics studies the design, manufacturing, programming, and control of the nanoscale robots.
A few generations from now someone diagnosed with cancer might be offered a new alternative to chemotherapy, the traditional treatment of radiation that kills not just cancer cells but healthy human cells as well, causing hair loss, fatigue, nausea, depression, and a host of other symptoms. A doctor practicing nanomedicine would offer the patient an injection of a special type of nanorobot that would seek out cancer cells and destroy them, dispelling the disease at the source, leaving healthy cells untouched. The extent of the hardship to the patient would essentially be a prick to the arm. A person undergoing a nanorobotic treatment could expect to have no awareness of the molecular devices working inside them, other than rapid betterment of their health. Nan medicine’s nanorobots are so tiny that they can easily traverse the human body. Scientists report the exterior of a nanorobot will likely be constructed of carbon atoms in a diamondoid structure because of its inert properties and strength. Super-smooth surfaces will lessen the likelihood of triggering the body's immune system, allowing the nanorobots to go about their business unimpeded. Glucose or natural body sugars and oxygen might be a source for propulsion, and the nanorobot will have other biochemical or molecular parts depending on its task. According to current theories, nanorobots will possess at least rudimentary two-way communication; will respond to acoustic signals; and will be able to receive power or even re-programming instructions from an external source via sound waves. A network of special stationary nanorobots might be strategically positioned throughout the body, logging each active nanorobot as it passes, and then reporting those results, allowing an interface to keep track of all of the devices in the body. A doctor could not only monitor a patient's progress but change the instructions of the nanorobots in vivo to progress to another stage of healing. When the task is completed, the nanorobots would be flushed from the body.
Nan medicine offers the prospect of powerful new tools for the treatment of human diseases and the augmentation of human biological systems. Diamondoid-based medical Nanorobotics may offer substantial improvements in capabilities over natural biological systems, exceeding even the improvements possible via tissue engineering and biotechnology. Nanorobots with completely artificial components have not been realized yet. The active area of research in this field is focused on molecular machines, which are thoroughly inspired by the nature’s way of doing things at nano-scale. The scope of this research is confined to nanomedical robots, in which the main objective is to provide a new alternative to chemotherapy treatment as a cure to leukemia. The mechanisms of leukemia, including the signs and symptoms, causes, the various treatments available as well as the sufferings of numerous side effects due to those treatments have to be well understood. Another research that is needed to be done is the concepts behind working principals behind nanorobots. Currently available conceptual nanorobots in the medicine field are used as reference, taking into accounts the assumptions made during the modeling stage. Selection of nonmaterial used in every parts of the nanorobot is essential and it is widely addressed. The key phase of nanorobot development is the navigation of the nanorobot inside the human body, removal of nanorobot from the human body and as well as its power source.
The first generation of nanorobots will likely fulfill very simple tasks, becoming more sophisticated as the science progresses. They will be controlled not only through limited design functionality but also through programming and the aforementioned acoustic signaling, which can be used, notably, to turn the nanorobots off.
Robert A. Freitas Jr., author of Nanomedicine, gives us an example of one type of medical nanorobot he has designed that would act as a red blood cell. It consists of carbon atoms in a diamond pattern to create what is basically a tiny, spherical pressurized tank, with "molecular sorting rotors" covering just over one-third of the surface. To make a rough analogy, these molecules would act like the paddles on a riverboat grabbing oxygen (O2) and carbon dioxide (CO2) molecules, which they would then pass into the inner structure of the nanorobot. The entire nanorobot which Freitas dubbed a respirocyte consists of 18-billion atoms and can hold up to 9-billion O2 and CO2 molecules, or just over 235 times the capacity of a human red blood cell. This increased capacity is made possible because of the diamond structure supports greater pressures than a human cell. Sensors on the nanorobot would trigger the molecular rotors to either release gasses, or collect them, depending on the needs of the surrounding tissues. A healthy dose of these nanorobots injected into a patient in solution, Freitas explains, would allow someone to comfortably sit underwater near the drain of the backyard pool for nearly four hours, or run at full speed for 15 minutes before taking a breath.
Early theories in The Engines of Creation (1986), by "the father of nanotechnology,” Eric Drexler, envisioned nanorobots as self-replicating. This idea is now obsolete but at the time the author offered a worst-case scenario as a cautionary note. Runaway microscopic nanobugs’ exponentially disassembling matter at the cellular level in order to make more copies of themselves - a situation that could rapidly wipe out all life on Earth by changing it into "gray goo." This unlikely but theoretically feasible ecophage triggered a backlash and blockade to funding. The idea of self-replicating nanobugs rapidly became rooted in many popular science fiction themes including Star Trek's nanoalien, the Borg.
Over the years MNT theory continued to evolve eliminating self-replicating nanorobots. This is reflected in Drexler's later work, Nan systems (1992). The need for more control over the process and position of nanomachines has led to a more mechanical approach, leaving little chance for runaway biological processes to occur.
Nanorobots are nanodevices that may be of about 3 to 5 micrometers in size. The individual parts used to make these nanorobots may be of 1 to 100 nm in size. These nanorobots are mainly made up of carbon, and may be given a coating of diamond. The diamond coat is given because diamond is the most inert and tough material ever known. These nanorobots can be used for a variety of purposes. To treat heart blocks we use three kinds of nanorobots. Nanorobots with nanosensors are used to locate the block. These robots will need four kinds of nanosensors
1. Pressure sensors
2. Acoustic sensors
3. Chemo sensors
4. Smart sensors
Nanorobots equipped with nanolasers to sever the block after confirmation.
Nanorobots that have the ability to fill the burnt gaps with fresh flawless cells synthesized by the robots themselves in order to prevent the recurrence of the block. This process is known as ‘molecular syntheses.
The three types of nanorobots needed for the process, are suspended in a liquid matrix and injected into blood vessels of the patient. Immediately the acoustic sensors in the sensor robots get activated and begin navigating the army of robots through the blood stream to the pericardium. Simultaneously, the smart sensors present in the sensor robots, get activated and form a closed ad-hoc network connecting all the robots. This is very essential in order to guide all the nanorobots to the desired location. The sensor robots perform the most sophisticated type of diagnosis known, i.e. diagnosis from the inside of the human body. These sensors, on reaching the periphery of the heart, scan the pericardial vessels, for blocks and locate the spot exactly. The pressure sensors mounted on the sensor robots, scan the blood vessels for variations in the blood pressure. This will act as the first confirmation. This scanning for pressure variations is necessary, as in the region of the block, there will be a constriction of the blood vessel and hence a rise in the blood pressure compared to that existing in the Size of nanorobots when compared to that of the red blood cells nearby areas. These sensors will generate a report of the potential areas of heart block, based on the pressure mapping of the blood vessels. The second confirmation comes from the chemo sensors. These sensors scan the region they traverse, for the chemical composition of the cholesterols. That is, these sensors differentiate the cholesterol compounds accumulated on the walls of the blood vessels, from the actual composition of the tissues of the blood vessels. In this way, the block can be identified accurately. All these information are transmitted through the ad- hoc network formed by all the smart sensors and can be constantly viewed by the doctors monitoring the entire process. After successful location of the block, the second type of nanorobots, those equipped with nanolasers, come into picture. These lasers, like the robots themselves, can be powered by the body itself, by means of the kinetic energy of the flowing blood, pressure of the blood flow, etc. thus, these lasers can be powered by the most ingenious ways imaginable. These laser robots on activation based on the information flow through the network, effectively burn down the block. Since the operation is held on a nanoscale, the outcome is highly accurate. Moreover, there is literally zero damage to the surrounding healthy tissues. The final leg of the operation is the responsibility of the molecular synthesizers. These nanorobots, take the required biochemical substances from the blood or the surrounding tissues, and synthesis the cells of the blood vessels in order to seal the area of the block. These cells are placed in the affected region and as a result, we have a whole new region of the blood vessel that is completely free from the threat of another block. Sensor robots then navigate the other robots through the blood stream.