There are many fraudulent websites, scaremongering articles, and conspiracy theories out on the internet about nanotechnology and nano-robots. If we put nanotechnology in the search bar of some famous search engines, a few of the most popular searches are “injectable nano-machines in humans”, “brain controlling nano-robots”, “nanotechnology spying” or simply “nanobots”. Most people ask questions like “does the COVID-19 vaccine contain nanobots?”, and so on. But if we put all these things aside and step into reality, we find that nanotechnology is something completely different.
Nanotechnology is the area of science that deals with the manipulation of materials on an atomic level, where phenomena take place on the nanometer scale. Nanotechnology is an emerging field of science that is being used now a day in a wide variety of fields like animal husbandry, medicine, agriculture, pharmaceutical science, and so on.
Nowadays nanobots are a very famous concept in current sci-fi movies and novels. A few decades ago nanobots were only a figment of imagination but nowadays they are revolutionizing fields of medicine and engineering. Although the nanobots shown in these movies and novels are a longshot from reality it’s not too far off. Today nanobots are expected to revolutionize the fields of medical diagnosis and drug delivery.
A robot is a machine capable of carrying out a complex series of actions automatically, especially one programmable by a computer. A nanobot is a robot scaled down to a few billionths of a meter. The field of nanorobotics brings together many different fields of science like nanofabrication which is used in the process of manufacturing devices such as nanomotors, nano actuators, nanosensors, and physical modeling at the dimensions of a few nanoscales.
Nanobot manufacturing follows two conventions top-down or bottom-up. The top-down way of manufacturing a nanobot mainly focuses on scaling down an existing machine to the size of a few nanometers. Whereas the bottom-up way of manufacturing refers to building a nanobot one atom at a time. Theoretically, specialized nanobots are known as ‘assemblers’ would be used to create these nanobots. These assemblers would use the bottom-up method and would stack atoms on top of each other much like a 3D printer to create the desired.
Researchers nowadays refer to molecules with unique properties that make them programmable to carry out specific tasks as nanobots. These nanobots are mostly self-propelled nano-motors and other bio-chemical substances composed of bio-nano components which are used to execute specific tasks in certain parts of the body or to carry drugs or other chemical substances to parts of the body that are otherwise inaccessible by any other methods.
For example, nanobots can be programmed to remove the blockage in arteries and veins in parts of the body where operating possesses a significant risk to the patient’s life.
Nanobots can be produced using a biochemical inorganic material such as metals or diamonds and organic materials such as polynucleotides and proteins. Metals can have many uses in the field of nanotechnology like silver has both the purpose of being used as the base of a nanobot and also as an antibiotic.
The surface properties of a nono robot are a key deciding factor for determining the solubility and interactions with other macromolecule and cells of the body. The dimensions of a nanobot affect directly their motion, reactivity, and cell membrane permeability. Depending on the type of fuel used for the creation of the nanobot, the propulsion mechanism can be bio-compatible that is, whether it can be used in the human body or not.
Detecting problems inside the body has always been a huge challenge for doctors and medical researchers, therefore researchers started working on super-small robots with optical cameras that could be sent inside the human body and capture pictures of the target location and provide an accurate view to the doctors. But the previous attempts at developing such robots were sub-par at best. The cameras used recorded unclear blurry distorted images. These cameras also had a limed field of view and couldn’t be easily controlled to get to the target area precisely.
But the researchers at Princeton University along with the University of Washington have overcome these obstacles and developed a super ultra-compact camera as published in a paper in Natural Communications. The size of the camera is comparable to the size of a coarse grain of salt. This newly developed camera can produce crisp, full-color images that are on par with the conventional cameras that are almost half a million times larger in size.
This camera could be fitted to a medical robot and perform minimally invasive endoscopy to diagnose various diseases and sometimes perform some minor treatment. An array of thousands of such cameras could turn any surface into a camera and help in getting full-scene sensing. This camera mainly relies on a technology called a ‘metasurface’, which is similar to a computer chip. Each metasurface is fitted with almost 1.6 million posts that are cylindrical in shape.
These posts are roughly around the size of 120 nanometers. Each post has a unique shape and dimension and functions much like an optical camera. These posts interact with light and produce various wavefronts. Machine learning-based algorithms are used to combine these wavefronts to produce a crisp full-sized image.
Sensors can be regarded as the eyes and ears of a nanobot and are arguably the most important component of the nanobot. Sensors can be of many different types for example biochemical sensors, mechanical sensors, optical sensors, and so on. Any sensor that uses any phenomenon at the nanoscale is regarded as a nanosensor. A biochemical nanosensor uses a biological or chemical reaction to detect target analytes and also for the treatment of various diseases.
An example of such a sensor in the medical field is the use of nano cantilevers as a Nano Electro-Mechanical System (NEMS). Sensors are mainly used for two purposes, the first being the use of sensors in detecting a target molecule, and the second is to find out the amount of damage that has been done to the body.
Sensors are very popular in today’s world due to their fast and efficient detection of the target molecules or survey a certain area inside the body with high accuracy. Cantilevers are highly sensitive and can produce a good atomic resolution for any surface, therefore they are widely used in Atomic Force Microscopy (AFM).
The main advantage of these sensors in nanobots is real-time detection and diagnosis. These nanobots have various functions like measuring cell mass, nucleic acids, and other biomolecules, they can also be used to detect specific molecules and can also be used to place nano-objects like drugs and other chemicals in a predetermined arrangement.
Controlling the movement of molecules in the nanometer scale is very difficult and poses a great challenge for researchers. Viscosity and the Brownian movement are a few of the reasons for such difficulty. Brownian movement refers to the random movement of particles caused by the collision between the molecules of the solvent.
Therefore, the main challenge faced by the researchers is how to make the nanobot such that it can overcome such properties of the fluid in the nanoscale and can achieve independent movement. Thus nanomotors were created. The main purpose of these nanomotors is to provide propulsion to the nanobots so as to achieve movement. The energy for propulsion is achieved by chemical reactions or electricity.
Nanobot propulsion is of two types external and internal. In the external approach, superconducting magnets were used in the early ’80s to facilitate the movement of nanobots. Nowadays MRI machines are used to achieve such results. This type of external propulsion has many advantages, for example, it provides superior control of the nanobot, i.e., the speed and direction of the nanobot can be controlled precisely, thus reducing the risk considerably.
The MRI can also be used to get real-time data from the nanobot and the effects it has on the body. Also, all movement of the nanobot is achieved with the help of an external machine thus there is no need for complicated nanomotors which consume a lot of power.
But in the case of internal propulsion, the best nanomotors are already present in nature itself for example cell division DNA transcription, synthesis of proteins, and so on. These are only a few of the numerous cases where chemical energy is responsible for movement.
How Nanobots work?
Most nanobots developed to date function by responding to certain external stimuli. These external stimuli can be a specific chemical reaction, change in temperature, or by exposing them to radio waves. There are many forms of nanobots that are currently available, some of them are stated below
As the name suggests, a nanorobotic switch functions the same as a normal switch, i.e., the nanobot may start a reaction by conformational changes (change in shape due to external stimuli) to the machine, like how we can open a book. These conformational changes are bought about by external stimuli. Scientists use external stimuli like temperature change, ultraviolet or infrared light, or certain chemical reactions to force the nanorobotics switches into specific positions to accomplish a specific task.
After acquiring correct stimuli, the nanomotor or motors are the ones with a comparatively complex structure that facilitates the physical movement of the nanobot by providing energy through chemical reactions or conformational changes.
A nanorobotics shuttle is a device much like a cargo truck, it can transport substances to various places. These shuttles can be used to transport specific drugs or chemicals to a determined place. These shuttles can be paired with nanomotors to achieve a higher degree of control over the nanobot for the precise delivery of substances.
A nanorobotic car is the most cutting-edge nanodevice developed in the field of nanorobotics so far. This device looks just like a car with four wheels. These cars can move independently with the help of light or chemical reactions. The main problem arises in controlling the nanodevice once it starts moving; scientists are still in the process of researching ways to control the movement of these nanomotors but no significant achievement has been made so far. Scientists have only figured out the method of using light to control the movement of these particles to a very small degree.
Applications of Nanobots
In spite of being a newer technology, the same has shown various mixed-type of reactions. However, the amount of applications shown is far more than the last expected issue. Among them, some of them are categorized below”-
Nowadays the main focus of researchers in the medical field is to develop minimally invasive techniques for the diagnosis and treatment of various diseases.
Nanorobotics Application in the field of Hematology
The research of nanorobotics application in the field of hematology is developing through leaps and bounds. The research ranges from developing nanobots with the same function as different cells of the body and carrying out their tasks with even higher speed and efficiency.
For example, Respirocytes are hypothetical nanobots that have the same function as red blood cells. These theoretical nanobots would be able to supply 200 times more respiratory gases like oxygen and carbon dioxide than a natural red blood cell. The use of such nanobots is enormous in case of emergencies where the patient has stopped breathing, these nanobots can be injected into the bloodstream to carry oxygen to vital organs of the body like the brain.
Clottocytes are another type of nanobot that could mimic platelets. These nanobots could gather at the sight of an injury and form a mesh-like structure to trap blood cells in order to stop bleeding. The efficiency of these colonocytes is said to be 10000 times that of normal platelets of the same volume.
Nanorobotics Application for Cancer Detection and Therapy
Cancer is one of the most dreadful diseases in the world. Cancer was deemed incurable a few years ago but advancement in medical research has led to early-stage cancer patients being cured. But even then people with late-stage cancer are still deemed incurable. Therefore, the detection of cancer in its earlier stages has become very important because the survival rates improve significantly with early detection.
Nanobots with enhanced chemical sensors in the body can be used to detect tumor cells in the body. These nanobots can also be used for treatment. Through specific programming, the nanobots can provide treatment in both the primary and metastatic phases of cancer. The major advantage of using nanobots for treatment is that they can provide targeted treatment. The conventional method of treatment of cancer has severe side effects that are caused by healthy cells of the body. The nanobots can be used to destroy the cancer cells without affecting the surrounding healthy cells.
Nanobots are no longer a figment of imagination or the words of a creative author. They are also no longer a theoretical concept or an idea just on paper. They are being continuously developed and improved. Researchers are still in the research and experimental phase. They are constantly researching in order to improve the various components of nanobots.
The main focus of this research is on nano-motors in order to achieve independent movement for the nanobot. Chemically, magnetic and acoustic-driven nanomotors have been developed, but for medical purposes, fuel-free and biocompatible nanobots should be developed. There is a lot of research that has been completed in the field of nanorobotics and a lot of research that still needs to be done in order to produce an independently functional nanobot. However, the rapid advancement in various fields like nanotechnology, biotechnology, microbiology, and computer science will surely lead to the creation of nanobots.