NANOROBOTICS: MEDICINE OF THE FUTURE · Nanorobotics is an emerging, advanced and multidisciplinary field that calls for scientific and technical expertise of medical, pharmaceutical,

www.wjpps.com Vol 7, Issue 8, 2018.

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Kad et al. World Journal of Pharmacy and Pharmaceutical Sciences

NANOROBOTICS: MEDICINE OF THE FUTURE

Dhanashree Kad*, Sachin Hodgar and Kiran Thorat

Assistant Professor, Department of Pharmaceutical Chemistry, Kasturi College of Pharmacy,

Shikrapur, 412208 Pune.

ABSTRACT

Nanorobotics is the technology of creating machines or robots at or

close to the microscopic scale of a nanometer (10−9 meters). More

specifically, nanorobotics refers to the still largely hypothetical

nanotechnology engineering discipline of designing and building

nanorobots, devices ranging in size from 0.1-10 micrometers and

constructed of nanoscale or molecular components. As no artificial

non-biological nanorobots have yet been created, they remain a

hypothetical concept. The names nanobots, nanoids, nanites or

nanomites have also been used to describe these hypothetical devices.

Nanorobotics is an emerging, advanced and multidisciplinary field that

calls for scientific and technical expertise of medical, pharmaceutical,

bio-medical, engineering as well as other applied and basic scientists.

Nanorobots differ from macro-world robots, specifically in their nano sized constructs.

Assembly and realization of nanorobots depend on the principles of molecular

nanotechnology and mechano-synthetic chemistry. Practically, these systems are nano-

electromechanical devices that are capable to carry out pre-programmed functions in a

reliable and accurate manner with the help of energy provided by a preinstalled nanomotor or

nano-machine. Due to their small size and wide functional properties, nanorobots have

created exceptional prospects in medical, biomedical and pharmaceutical applications.

Although, no technology is available to construct artificial nanorobots, it is now possible to

create nanorobots by using biological means. The review presents a brief discussion on basic

nano-robotics and its possible applications in medical, biomedical and pharmaceutical

research.

WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES

SJIF Impact Factor 7.421

Volume 7, Issue 8, 1393-1416 Review Article ISSN 2278 – 4357

Article Received on

21 June 2018,

Revised on 10 July 2018,

Accepted on 31 July 2018

DOI: 10.20959/wjpps20188-12191

*Corresponding Author

Ms. Dhanashree Kad

Assistant Professor,

Department of

Pharmaceutical Chemistry,

Kasturi College of

Pharmacy, Shikrapur,

412208 Pune.


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KEYWORDS: Nanotechnology, Nanomedicine, Nanomachines, Nanomotors,

Bionanorobots.

INTRODUCTION

The need for targeted drug delivery systems is increasing as today‘s biomedical technologies

request new, innovative systems to replace difficult procedures. By developing a micro-scale

delivery system we hope to replace the need for traditional methods and

instruments. Biomedical micro-robots are one possible solution to this and various other

medical challenges. Nanomedicine offers the prospect of powerful new tools for the

treatment of human diseases and the improvement of human biological systems by

engineering nano/micro-scale robots that travel throughout the human body we can

implement new technologies that re-define conventional processes.

―Nanomedicine‖ is the process of diagnosing, treating, and preventing disease and traumatic

injury, of relieving pain, and of preserving and improving human health, using molecular

tools and molecular knowledge of the human body. Nanorobots would constitute

any ―smart‖ structure capable of actuation, sensing, signaling, information processing,

intelligence, manipulation and swarm behavior at nano scale (10-9m).[1,2]

Bio Nanorobots are Nanorobots designed (and inspired) by harnessing properties of

biological materials (peptides, DNAs), their designs and functionalities. These are inspired

not only by nature but machines too. Nanorobots could propose solutions at most of the

nanomedicine problems. Nanomedicine mainly refers to application of nanotechnology in

medicine. Nanotechnology refers to the science and engineering activities at the level of

atoms and molecules. 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 hydrogen atom. Nanorobots can offer a

number of advantages over current methods such as.[3]

i. Use of nanorobot drug delivery systems with increased bioavailability.

ii. Targeted therapy such as only malignant cells treated;

iii. Fewer mistakes on account of computer control and automation;

iv. Reach remote areas in human anatomy not operatable at the surgeon‘s operating table;

v. As drug molecules are carried by nanorobots and released where needed the advantages

of large interfacial area during mass transfer can be realized;

vi. Non-invasive technique;


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vii. Computer controlled operation with nobs to fine tune the amount, frequency, time of

release;

viii. Better accuracy;

The word "nanobot" (also "nanite", "nanogene", or "nanoant") is often used to indicate this

fictional context and is an informal or even pejorative term to refer to the engineering

concept of nanorobots. The word nanorobot is the correct technical term in the nonfictional

context of serious engineering studies. Some proponents of nanorobotics, in reaction to the

grey goo scare scenarios that they earlier helped to propagate, hold the view that nanorobots

capable of replication outside of a restricted factory environment do not form a necessary

part of a purported productive nanotechnology, and that the process of self-replication, if it

were ever to be developed, could be made inherently safe . They further assert that free-

foraging replicators are in fact absent from their current plans for developing and using

molecular manufacturing.

History of Nanorobots

1980‘s by Nobel Prize laureate Richard Smalley. Smalley has extended his vision to carbon

nanotubes, discovered by Sumio Iijima, which he envisions as the next super interconnection

for ultra small electronics. The term nanotechnology has evolved to mean the manipulation of

the elements to create unique and hopefully useful structures.[4]

December 29, 1959: Richard Feynman gives the famous ―There‘s Plenty of Room at the

Bottom‖ talk. First use of the concepts of nanotechnology. Describes an individual atoms

and molecules can be manipulated.

1974: Professor Norio Taniguchi defines nanotechnology as ―the processing of,

separation, consolidation, and deformation of materials by atom / molecule.‖

1980‘s: Dr. Eric Drexler publishes several scientific articles promoting nanoscale

phenomena and devices.

1986: The book Engines of Creation: The Coming Era of Nanotechnology by Dr. Eric

Drexler is published. He envisioned nanorobots as self replicating. A first book on

nanotechnology.

Recently, researched chemical and biomedical engineering have used carbon nano tubes as a

vessel for delivering drugs into the body.


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Components of Nanorobot

The various components in nanorobot include power supply, fuel buffer tank, sensors,

motors, manipulators, onboard computers, pumps, pressure tanks and structural support. The

substructures in a nanorobot include.

1. Payload: This void section holds a small dose of drug/medicine. The nanorobots could

transverse in the blood and release the drug to the site of infection/injury.

2. Micro camera: The nanorobot may include a miniature camera. The operator can steer the

nanorobot when navigating through the body manually.[5,6]

3. Electrodes: The electrode mounted on the nanorobot could form the battery using the

electrolytes in the blood. These protruding electrodes could also kill the cancer cells by

generating an electric current, and heating the cells up to death.

4. Lasers: These lasers could burn the harmful material like arterial plaque, blood clots or

cancer cells.[5]

5. Ultra sonic signal generators: These generators are used when the nanorobot are used to

target and destroy kidney stones.

6. Swimming tail: The nanorobot will require a means of propulsion to get into the body as

they travel against the flow of blood in the body.

The nanorobot will have motors for movement and manipulator arms or mechanical leg for

mobility. The two main approaches followed in construction of Nanorobots are Positional

assembly and Self assembly. In self assembly, the arm of a miniature robot or a microscopic

set is used to pick the molecules and assemble manually. In positional assembly, the

investigators will put billions of molecules together and let them automatically assemble

based on their natural affinities into the desired configuration.[6, 7, and 8]

Nanorobot Control

Design is the software developed for simulating nanorobots in environment with fluids which

is dominated by Brownian motion.[8]

The nanorobots have chemical sensors which can detect

the target molecules.

The nanorobots are provided with swarm intelligence for decentralization activity. Swarm

intelligence techniques are the algorithms designed for artificial intelligence of the nanorobot.

The swarm intelligence technique is been inspired by the behavior of social animals such as

ants, bees and termites which work collaboratively without a centralized control. The three

main types of swarm intelligence techniques deigned are ant colony optimization (ACO),

artificial bee colony (ABC) and particle swarm optimization (PSO).[10]


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Types of Nanorobot

The types of nanorobots designed by Robert A. Freitas Jr as artificial blood are.

i. Respirocytes: Respirocytes are the nanorobots designed as artificial mechanical red blood

cells which are blood borne spherical 1 µm diameter size. The outer shell is made of

diamonded 1000 atm pressure vessel with reversible molecule-selective pumps.[11, 12]

Respirocytes carry oxygen and carbon dioxide molecules throughout the body. The

Respirocytes is constructed of 18 billion atoms which are precisely arranged in a diamondoid

pressure tanks that can store up to 3 billion oxygen and carbon dioxide molecules.[11]

The

respirocyte would deliver 236 times more oxygen to the body tissues when compared to

natural red blood cells. The respirocyte could manage the carbonic acidity which will be

controlled by gas concentration sensors and an onboard nanocomputer.[12]

The stored gases

are released from the tank in a controlled manner through molecular pumps. The respirocytes

exchange gases via molecular rotors. The rotors have special tips for particular type of

molecule.[13]

Each respirocyte consists of 3 types of rotors. One rotor releases the stored

oxygen while travelling through the body. The second type of rotor captures all the carbon

dioxide in the blood stream and release at the lungs while the third rotor takes in the glucose

from blood stream as fuel source.[14,13]

There are 12 identical pumps which are laid around

the equator; oxygen rotors on the left, water rotors in the middle and carbon dioxide rotors in

the left. There are gas concentration sensors on the surface of respirocyte.

When the respirocyte passes through the lung capillaries, O2 partial pressure will be high and

CO2 partial pressure will be low, therefore the onboard nanocomputer commands the sorting

rotors to load in oxygen and release the carbon dioxide molecules.[6]

The water ballast

chambers aid in maintaining buoyancy. The respirocytes can be programmed to scavenge

carbon monoxide and other poisonous gases from the body.

The respirocyte works as an artificial erythrocyte by mimicking the oxygen and carbon

dioxide transport functions. A 5 cc therapeutic dose of 50% respirocyte saline suspension

containing 5 trillion nanorobots would exactly replace the gas carrying capacity of the

patient‘s entire 5.4 liters of blood. Once the therapeutic purpose is served, the respirocyte

may be extracted from circulation, requiring respirocyte activating protocol. During this

protocol called nanapheresis, the blood to be cleared would be passed from the patient to a

specialized centrifugation apparatus where the ultrasonic transmitters command the

respirocyte to maintain neutral buoyancy. There are no other solid blood components that can


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maintain neutral buoyancy; hence those components are precipitate outwards during

centrifugation. The blood components are added back to filtered plasma. The filtered plasma

is recombined with centrifuged solid blood components and then returned undamaged to the

patient‘s body.[11]

An artificial red cell—the respirocyte designed by Robert A.Freitas Jr is

given in fig. 1.

Fig 1: An artificial red cell—the respirocyte designed by Robert A.Freitas Jr.

ii. Microbivores: Microbivores are the nanorobot which functions as artificial white blood

cell and also known as nanorobotic phagocytes. The microbivore is a spheroid device made

up of diamond and sapphire which measures 3.4 µm in diameter along its major axis and 2.0

µm diameter along minor axis and consists of 610 billion precisely arranged structural atoms.

It traps in the pathogens present in the blood stream and break down to smaller molecules.

The main function of microbivore is to absorb and digest the pathogens in the blood stream

by the process of phagocytosis. The microbivore consist of 4 fundamental components.

An array of reversible binding sites.

An array of telescoping grapples.

A morcellation chamber.

Digestion chamber[15]

During the cycle of operation, the target bacterium binds to the microbivore surface via

species-specific reversible binding site. A collision between the bacterium and the

microbivore brings in the surface into intimate contact, allowing the reversible binding site to

recognize and weakly bind to the bacterium. A set of 9 different antigenic markers should be

specific and confirm the positive binding event confirming the presence target microbe.

There would be 20,000 copies of the 9 marker sets distributed in 275 disk shaped regions

across microbivore. When the bacterium is bound to the binding site, the telescopic robotic

grapples rise up from the surface and attach to the trapped bacterium thereby establishing a


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secure anchorage. The grapple‘s handoff motion can transport the bacterium from binding

site to the ingestion port. Further the bacterium is internalized into the morcellation chamber

where in the bacterium is minced into nanoscale pie. The remains are pistoned into the

digestion chamber which consists of a pre-programmed set of digestive enzymes. :

Mechanism of phagocytosis by microbivore is given in fig 2.

.

Fig. 2: Mechanism of phagocytosis by microbivore.

These enzymes are injected and extracted 6 times during a single digestion cycle, where in

the morcellate is progressively reduced into amino acids, mononucleotides, free fatty acid and

simple sugars. These small molecules are then discharged into the blood stream through the

exhaust port. After the destruction of pathogens the microbivores exits the body through the

kidneys and are then excreted in urine.An entire cycle of phagocytosis by microbivore will be

completed in 30 seconds. There are no chances of septic shock or sepsis as the bacterial

components are internalized and digested into non-antigenic biomolecules.[14]

The

microbivore is 1000 times faster acting than antibiotic aided white blood cells and the

pathogen stand no chance of multiple drug resistance. They can also be used to clear

respiratory, cerebrospinal bacterial infection or infections in urinary fluids and synovial

fluids.

iii. Clottocytes: Hemostasis is the process of blood clotting when there is damage to the

endothelium cells of blood vessels by platelets. These platelets can be activated by collision

of exposed collagen from damaged blood vessels to the platelets. The whole process of

natural blood clotting can take 2-5 minutes. The nanotechnology has shown the capabilities

of reducing the clotting time and reducing the blood loss. In certain patients, the blood clots

are found to occur irregularly. This abnormality is treated using drugs such corticosteroids.


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The treatment with corticosteroids is associated with side effects such as hormonal secretions;

blood/platelet could damage lungs and allergic reactions.[16]

Blood clotting mechanism of

clottocytes is gien in fig 3.

Fig. 3: Blood clotting mechanism of clottocytes.

The theoretically designed clottocyte describes artificial mechanical platelet or clottocyte that

would complete hemostasis in approximately 1 sec. It is spherical nanorobot powered by

serum-oxyglucose approximately 2 µm in diameter containing a fiber mesh that is compactly

folded onboard. The response time of clottocyte is 100-1000 times faster than the natural

hemostatic system.[15]

The fiber mesh would be biodegradable and upon release, a soluble

film coating of the mesh would dissolve in contact with the plasma to expose sticky mesh.[17]

Reliable communication protocols would be required to control the coordinated mesh release

from neighboring clottocytes and also to regulate multi-device-activation radius within the

local clottocyte population. As clottocyte-rich blood enters the injured blood vessel, the

onboard sensors of clottocyte rapidly detects the change in partial pressure, often indicating

that it is bled out of body. If the first clottocyte is 75 µm away from air-serum interface,

oxygen molecules from the air diffuse through serum at human body temperature. This

detection would be broadcasted rapidly to the neighboring clottocytes through acoustic

pulses. This allows rapid propagation of a carefully controlled device-enablement cascade.

The stickiness in the fiber mesh would be blood group specific to trap blood cells by binding

to the antigens present on blood cells. Each mesh would overlap on the neighboring mesh and

attract the red blood cells to immediately stop bleeding.[15]

The clotting function by clottocyte is essentially equivalent to that of natural platelets at about

1/10,000th the concentration in the blood stream i.e. 20 clottocytes per cubic milimeter of

blood.[18]

The major risk associated with the clottocytes is that the additional activity of the


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mechanical platelets could trigger the disseminated intravascular coagulation resulting in

multiple micro thrombi.

Onboard Computers of Nanorobot

Functions that are controlled by the onboard computer include.

1. Pumping: Molecular pumps would be a primary system in nanorobots like respirocyte

and pharmacyte. Single-molecule recognition, sorting and pumping via molecular sorting

rotors to allow molecule-by-molecule exchange with in the environment.

2. Sensing: Chemical, pressure, temperature sensors, electromagnetic, magnetic, optical

sensors, gravity, position/orientation sensors, molecular recognition sites. The nanorobot

of approximately 1 micron diameter could employ approximately 104-10

5 sensors of

various kinds for controlling the device.

3. Configuration: Control of device shape; gas-driven extensible bumpers to maintain

physical contact among adjacent device, control of internal ballasting for nanapheresis

and control of chemical ligands for hull displays, for controlled adhesion regulation of

external surfaces.

4. Energy: Control of onboard power generation or power receiver systems including

thermal, mechanical, acoustic, chemical, electrical, photonic, or nuclear sources;

management of onboard energy storage; controlling the transduction, conditioning, and

conversion of tethered energy sources; and control of internal power distribution and load

balancing throughout a nanorobotic device.

5. Communication: Control of communications hardware including receivers and

transmitters, whether chemical, acoustic, electromagnetic, or other modality;

interpretation of received signals as new commands from the physician; replacement of

existing operating parameters with new ones and out messaging, coordination of

nanorobot populations to accurately transfer information directly to or from the patient.

6. Navigation: Establishing absolute or relative physical position across many regimes

including bloodstream, tissues, organs, and cells; positional navigation by dead

reckoning, cartotaxis, macro/micro transponder networks.

7. Manipulation: Deployment and actuation of manipulators including ciliary, pneumatic,

or telescoping systems; stowage, retrieval, selection, installation, use, and detachment of

tooltips and other end-effectors; management of tool and manipulator garages;

management of coordinated manipulator arrays; and control of onboard disposal or


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disassembly systems including morcellation, grinding, sonication, thermal or chemical

decomposition systems.

8. Locomotion: Control of specific in vivo locomotion systems including ciliary or grapple

systems, surface deformation, inclined planes/screws, volume displacement, and viscous

anchoring systems; control of locomotion across cell-coated tissue surfaces, amoeboid

motion or inchworm locomotion.[15]

Some scientists are looking at the world of

microscopic organisms for inspiration. Paramecium move through their environment

using tiny tail-like limbs called cilia. By vibrating the cilia, the paramecium can swim in

any direction. Similar to cilia are flagella, which are longer tail structures. Organisms

whip flagella around in different ways to move around. Locomotion of Nanorobots is

given in fig 4.

Fig 4: Locomotion of Nanorobots.

Elements of Nanorobots

Carbon will likely be the principal element comprising the bulk of a medical nanorobot,

probably in the form of diamond or diamondoid/fullerene nanocomposites. Many other light

elements such as hydrogen, sulfur, oxygen, nitrogen, fluorine, silicon, etc. will be used for

special purposes in nanoscale gears and other components. The chemical inertness of

diamond is proved by several experimental studies. One such experiment conducted on

mouse peritoneal macrophages cultured on DLC showed no significant excess release of

lactate dehydrogenase or of the lysosomal enzyme beta N-acetyl-Dglucosaminidase (an

enzyme known to be released from macrophages during inflammation). Morphological

examination revealed no physical damage to either fibroblasts or macrophages, and human

osteoblast like cells confirming the biochemical indication that there was no toxicity and that


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no inflammatory reaction was elicited in vitro. The smoother and more flawless the diamond

surface, the lesser is the leukocyte activity and fibrinogen adsorption. An experiment by Tang

et al. showed that CVD diamond wafers implanted intraperitoneally in live mice for 1 week

revealed minimal inflammatory response. Interestingly, on the rougher ―polished‖ surface, a

small number of spread and fused macrophages were present, indicating that some activation

had occurred. The exterior surface with near-nanometer smoothness results in very low

bioactivity. Due to the extremely high surface energy of the passivated diamond surface and

the strong hydrophobicity of the diamond surface, the diamond exterior is almost completely

chemically inert. The typical size of a blood born medical nanorobot will be 0.5-3

micrometers as it is the maximum size that can be permitted due to capillary passage

requirement. These nanorobots would be fabricated in desktop nanofactories specialized for

this purpose. The capacity to design, build, and deploy large numbers of medical nanorobots

into the human body would, make possible the rapid elimination of disease and the effective

and relatively painless recovery from physical trauma. Medical nanorobots can be of great

importance in easy and accurate correction of genetic defects, and help to ensure a greatly

expanded health span.

Nanorobots: What Are They?

Nanorobots are theoretical microscopic devices measured on the scale of nanometers (1nm

equals one millionth of 1 millimeter). When fully realized from the hypothetical stage, they

would work at the atomic, molecular and cellular level to perform tasks in both the medical

and industrial fields that have heretofore been the stuff of science fiction. Nanomedicine'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.

Nanomachines are largely in the research and- development phase, but some primitive

molecular machines have been tested. An example is a sensor having a switch approximately

1.5 nanometers across, capable of counting specific molecules in a chemical sample. The first

useful applications of nanomachines, if such are ever built, might be in medical technology,

where they might be used to identify cancer cells and destroy them. Another potential

application is the detection of toxic chemicals, and the measurement of their concentrations,


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in the environment. Recently, Rice University has demonstrated a single-molecule car which

is developed by a chemical process and includes buckyballs for wheels. It is actuated by

controlling the environmental temperature and by positioning a scanning tunneling

microscope tip.[19]

Approaches of Nanorobots

Biochip: The joint use of nanoelectronics, photolithography, and new biomaterials, can be

considered as a possible way to enable the required manufacturing technology towards

nanorobots for common medical applications, such as for surgical instrumentation,

diagnosis and drug delivery. Indeed, this feasible approach towards manufacturing on

nanotechnology is a practice currently in use from the electronics industry.So, practical

nanorobots should be integrated as nanoelectronics devices, which will allow tele-

operation and advanced capabilities for medical instrumentation.[20]

Nubots: Nubot is an abbreviation for "nucleic acid robots." Nubots are synthetic robotics

devices at the nanoscale. Representative nubots include the several DNA walkers reported

by Ned Seeman's group at NYU, Niles Pierce's group at Caltech, John Reif's group at

Duke University, Chengde Mao's group at Purdue, and Andrew Turberfield's group at the

University of Oxford.

Positional nanoassembly: Nanofactory Collaboration[6]

, founded by Robert Freitas and

Ralph Merkle in 2000, is a focused ongoing effort involving 23 researchers from 10

organizations and 4 countries that is developing a practical research agenda specifically

aimed at developing positionally-controlled diamond mechanosynthesis and a

diamondoid nanofactory that would be capable of building diamondoid medical

nanorobots.[21]

Bacteria based: This approach proposes the use biological microorganisms, like

Escherichia coli bacteria. Hence, the model uses a flagellum for propulsion purposes. The

use of electromagnetic fields are normally applied to control the motion of this kind of

biological integrated device, although his limited applications.

Open Technology: A document with a proposal on nanobiotech development using open

technology approaches has been addressed to the United Nations General Assembly.

According to the document sent to UN, in the same way Linux and Open Source has in

recent years accelerated the development of computer systems, a similar approach should

benefit the society at large and accelerate nanorobotics development.[22]


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The use of nanobiotechnology should be established as a human heritage for the coming

generations, and developed as an open technology based on ethical practices for peaceful

purposes.

Making Nanorobots

Research and design of drug-carrying nanorobots is not new. Scientists have already created

nanobot prototypes by using advanced molecular design software to create nanostructures

that can store various molecular cargo.

Using a method known as ‗DNA origami‘, pioneered in 2006 by scientist Paul Rothemund

from Caltech University in the U.S., scientists have been able to manipulate DNA material

into specific shapes and even program the 3-D DNA structures to carry out very basic robotic

tasks, such as fusing to other cells and operating within other DNA material.

However, the DNA nanorobots created so far have faced challenges in movement, activation

and targeting of drug release. Although DNA nanorobots have already been programmed to

carry cargo and work in conjunction with other nanorobots, this new study is the first time

that structural techniques have been exploited by advanced computing functions to securely

deliver treatment to specific diseased cells.

How It Works

Instead of building a single complex molecule to identify multiple features of a cell surface,

Dr. Stojanovic and his colleagues at Columbia used a different, and potentially easier,

approach based on multiple simple molecules, which together form a robot (or automaton, as

the authors prefer calling it).

To identify a cell possessing three specific surface proteins, Dr. Stojanovic first constructed

three different components for molecular robots. Each component consisted of a piece of

double-stranded DNA attached to an antibody specific to one of the surface proteins. When

these components are added to a collection of cells, the antibody portions of the robot bind to

their respective proteins (in the figure, CD45, CD3, and CD8) and work in concert.

On cells where all three components are attached, a robot is functional and a fourth

component (labeled 0 below) initiates a chain reaction among the DNA strands. Each

component swaps a strand of DNA with another, until the end of the swap, when the last

antibody obtains a strand of DNA that is fluorescently labeled. At the end of the chain


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reaction- which takes less than 15 minutes in a sample of human blood-only cells with the

three surface proteins are labeled with the fluorescent marker.

"We have demonstrated our concept with blood cells because their surface proteins are well

known, but in principle our molecules could be deployed anywhere in the body," Dr.

Stojanovic said. In addition, the system can be expanded to identify four, five, or even more

surface proteins.

Nanotechnology is the creation of fully mechanical machine with its physical or its

components size very close to the nanometre range. Nanorobots are programmable

assemblies of nanometer scale components constructed by manipulating macro/micro devices

or by self assembly on pre-programmed templates or scaffolds . Nanorobots are essentially

nanoelectromechanical devices (NEMS). These nanorobotic devices are comparable to

biological cells and organelles in size. The technology of design, fabrication, and

programming of these nanorobotsis known as Nanorobotics. It is a multidisciplinary field

requiring advanced level input from different areas of science and technology including,

physics, chemistry, biology, medicine, pharmaceutical sciences, engineering, biotechnology

and other biomedical sciences.

Nanorobotics is the technology of creating machines or robots at or close to the scale of a

nanometre (10-9 metres). More specifically, nanorobotics refers to the still largely theoretical

nanotechnology engineering discipline of designing and building nanorobots. Nanorobots

(nanobots or nanoids) are typically devices ranging in size from 0.1- 10 micrometres 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. Another definition

sometimes used is a robot which allows precision interactions with nanoscale objects, or can

manipulate with nanoscale resolution.

Following this definition even a large apparatus such as an atomic force microscope can be

considered a nanorobotic instrument when configured to perform nanomanipulation. Also,

macroscale robots or microrobots which can move with nanoscale precision can also be

considered nanorobots2. Initial uses of nanorobots to health care are likely to emerge within

the next ten years with potentially broad biomedical applications. The ongoing developments

of molecular-scale electronics, sensors and motors are expected to enable microscopic robots

with dimensions comparable to bacteria. Recent developments on the field of biomolecular


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computing has demonstrated positively the feasibility of processing logic tasks by bio-

computers, which is a promising first step to enable future nano processors with increasingly

complexity. Studies in the sense of building biosensors and nano-kinetic devices, which is

required to enable nanorobots operation and locomotion, has been advanced recently too.[4]

Fields of Application

Some possible applications using nanorobots are as follows:

1. To cure skin diseases, a cream containing nanorobots may be used. It could remove the

right amount of dead skin, remove excess oils, add missing oils, apply the right amounts of

natural moisturising compounds, and even achieve the elusive goal of 'deep pore cleaning' by

actually reaching down into pores and cleaning them out. The cream could be a smart

material with smooth-on, peeloff convenience.

2. A mouthwash full of smart nanomachines could identify and destroy pathogenic bacteria

while allowing the harmless flora of the mouth to flourish in a healthy ecosystem. Further,

the devices would identify particles of food, plaque, or tartar, and lift them from teeth to be

rinsed away. Being suspended in liquid and able to swim about, devices would be able to

reach surfaces beyond reach of toothbrush bristles or the fibres of floss. As short-lifetime

medical nanodevices, they could be built to last only a few minutes in the body before falling

apart into materials of the sort found in foods (such as fibre).

3. Medical nanodevices could augment the immune system by finding and disabling

unwanted bacteria and viruses. When an invader is identified, it can be punctured, letting its

contents spill out and ending its effectiveness. If the contents were known to be hazardous by

themselves, then the immune machine could hold on to it long enough to dismantle it more

completely.

4. Devices working in the bloodstream could nibble away at arteriosclerotic deposits,

widening the affected blood vessels. Cell herding devices could restore artery walls and

artery linings to health, by ensuring that the right cells and supporting structures are in the

right places. This would prevent most heart attacks.

Nanorobotics in Dentistry

The growing interest in the future of dental applications of nanotechnology is leading to the

emergence of a new field called Nanodentistry. Nanorobots induce oral analgesia,

Desensitize tooth, manipulate the tissue to re-align and straighten irregular set of teeth and to


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improve durability of teeth. Further it is explained that how nanorobots are used to do

preventive, restorative, curative procedures.

Major tooth repair: Nanodental techniques involve many tissue engineering procedures for

major tooth repair. Mainly nanorobotics manufacture and installation of a biologically

autologous whole replacement tooth that includes both mineral and cellular components

which leads to complete dentition replacement therapy.

Tooth Durability and Appearance: Nanodentistry has given material that is nanostructured

composite material, sapphire which increases tooth durability and appearance. Upper enamel

layers are replaced by covalently bonded artificial material such as sapphire. This material

has 100 to 200 times the hardness and failure strength than ceramic. Like enamel, sapphire is

a somewhat susceptible to acid corrosion. Sapphire has best standard whitening sealant,

cosmetic alternative. New restorative nano material to increase tooth durability is

Nanocomposites. This is manufactured by nanoagglomerated discrete nanoparticles that are

homogeneously distributed in resins or coatings to produce nanocomposites. The nanofiller

include an aluminosilicate powder having a mean particle size of about 80nm and a 1:4ratio

of alumina to silica. The nanofiller has a refractive index of 1.503, it has superior hardness,

modulous of elasticity, translucency, esthetic appeal, excellent color density, high polish and

50% reduction in filling shrinkage. They are superior to conventional composites and blend

with a natural tooth structure much better.

Nano Impression: Impression material is available with nanotechnology application.

Nanofiller are integrated in the vinylpolysiloxanes, producing a unique addition siloxane

impression material. The main advantage of material is it has better flow, improved

hydrophilic properties hence fewer voids at margin and better model pouring, enhanced detail

precision.

Nanomedicine

Potential applications for nanorobotics in medicine include early diagnosis and targeted drug

delivery for cancer biomedical instrumentation, surgery, pharmacokinetics, monitoring of

diabetes, and health care.[9]

In such plans, future medical nanotechnology is expected to

employ nanorobots injected into the patient to perform treatment on a cellular level. Such

nanorobots intended for use in medicine should be non-replicating, as replication would

needlessly increase device complexity, reduce reliability, and interfere with the medical


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mission. Instead, medical nanorobots are posited to be manufactured in hypothetical,

carefully controlled nanofactories in which nanoscale machines would be solidly integrated

into a supposed desktop-scale machine that would build macroscopic products.[4]

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 blood stream. Nanorobots may treat conditions like arteriosclerosis is given in

fig 5.

Fig 5: Nanorobots may treat conditions like arteriosclerosis.

Nanorobots in Cancer Detection and Treatment

Cancer can be successfully treated with current stages of medical technologies and therapy

tools. However, a decisive factor to determine the chances for a patient with cancer to survive

is: how earlier it was diagnosed; what means, if possible, a cancer should be detected at least

before the metastasis has began. Another important aspect to achieve a successful treatment

for patients, is the development of efficient targeted drug delivery to decrease the side effects

from chemotherapy. Phagocytosis process by Nanorobots is given in fig 6.

Fig 6: Phagocytosis process by Nanorobots.


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Considering the properties of nanorobots to navigat as bloodborne devices, they can help on

such extremely important aspects of cancer therapy. Nanorobots with embedded chemical

biosensors can be used to perform detection of tumor cells in early stages of development

inside the patient's body. Integrated nanosensors can be utilized for such a task in order to

find intensity of E-cadherin signals.Therefore a hardware architecture based on

nanobioelectronics is described for the application of nanorobots for cancer therapy. Analyses

and conclusions for the proposed model is obtained through real time 3D simulation.[23]

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 kidney stones using a small laser. Breaking up kidney

stones mechanism by Nanorobots is given in fig 7.

Fig 7: Breaking up kidney stones mechanism by Nanorobots.

Nanorobots in the Diagnosis and Treatment of Diabetes

Glucose carried through the blood stream is important to maintain the human metabolism

working healthfully, and its correct level is a key issue in the diagnosis and treatment of

diabetes. Intrinsically related to the glucose molecules, the protein hSGLT3 has an important

influence in maintaining proper gastrointestinal cholinergic nerve and skeletal muscle

function activities, regulating extracellular glucose concentration. The hSGLT3 molecule can

serve to define the glucose levels for diabetes patients. The most interesting aspect of this

protein is the fact that it serves as a sensor to identify glucose.[24]

The simulated nanorobot prototype model has embedded Complementary Metal Oxide

semiconductor (CMOS) nanobioelectronics. It features a size of ~2 micronmeter, which


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permits it to operate freely inside the body. Whether the nanorobot is invisible or visible for

the immune reactions, it has no interference for detecting glucose levels in blood stream.

Even with the immune system reaction inside the body, the nanorobot is not attacked by the

white blood cells due biocompatibility. For the glucose monitoring the nanorobot uses

embedded chemosensor that involves the modulation of hSGLT3 protein glucosensor

activity. Through its onboard chemical sensor, the nanorobot can thus effectively determine if

the patient needs to inject insulin or take any further action, such as any medication clinically

prescribed. The image of the NCD simulator workspace shows the inside view of a venule

blood vessel with grid texture, red blood cells (RBCs) and nanorobots. They flow with the

RBCs through the bloodstream detecting the glucose levels. At a typical glucose

concentration, the nanorobots try to keep the glucose levels ranging around 130 mg/dl as a

target for the Blood Glucose Levels (BGLs). A variation of 30mg/dl can be adopted as a

displacement range, though this can be changed based on medical prescriptions. In the

medical nanorobot architecture, the significant measured data can be then transferred

automatically through the RF signals to the mobile phone carried by the patient. At any time,

if the glucose achieves critical levels, the nanorobot emits an alarm through the mobile

phone.

Nanorobots in Surgery

Surgical nanorobots could be introduced into the body through the vascular system or at the

ends of catheters into various vessels and other cavities in the human body. A surgical

nanorobot, programmed or guided by a human surgeon, could act as an semiautonomous on-

site surgeon inside the human body. Such a device could perform various functions such as

searching for pathology and then diagnosing and correcting lesions by nanomanipulation,

coordinated by an on-board computer while maintaining contact with the supervising surgeon

via coded ultrasound signals. The earliest forms of cellular nanosurgery are already being

explored today. For example, a rapidly vibrating (100 Hz) micropipette with a <1 micron tip

diameter has been used to completely cut dendrites from single neurons without damaging

cell viability. Axotomy of roundworm neurons was performed by femtosecond laser surgery,

after which the axons functionally regenerated. A femtolaser acts like a pair of ―nano-

scissors‖ by vaporizing tissue locally while leaving adjacent tissue unharmed.[25]


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Nanorobots in Gene Therapy

Medical nanorobots can readily treat genetic diseases by comparing the molecular structures

of both DNA and proteins found in the cell to known or desired reference structures. Any

irregularities can then be corrected, or desired modifications can be edited in place. In some

cases, chromosomal replacement therapy is more efficient than in cytorepair. Floating inside

the nucleus of a human cell, an assembler-built repair vessel performs some genetic

maintenance. Stretching a supercoil of DNA between its lower pair of robot arms, the

nanomachine gently pulls the unwound strand through an opening in its prow for analysis.[26]

Upper arms, meanwhile, detach regulatory proteins from the chain and place them in an

intake port. The molecular structures of both DNA and proteins are compared to information

stored in the database of a larger nanocomputer positioned outside the nucleus and connected

to the cell-repair ship by a communications link. Irregularities found in either structure are

corrected and the proteins reattached to the DNA chain, which re-coils into its original form.

With a diameter of only 50 nanometers, the repair vessel would be smaller than most bacteria

and viruses, yet capable of therapies and cures well beyond the reach of present-day

physicians. With trillions of these machines coursing through a patient's bloodstream,

"internal medicine" would take on new significance. Disease would be attacked at the

molecular level, and such maladies as cancer, viral infections and arteriosclerosis could be

wiped out.

Diagnosis and Testing

Medical nanorobots can perform a vast array of diagnostic, testing and monitoring functions,

both in tissues and in the bloodstream. These devices could continuously record and report all

vital signs including temperature, pressure, chemical composition, and immune system

activity, from all different parts of the body. Nanorobots swallowed by a patient for

diagnostic purposes approach the surface of the stomach lining to begin their search for signs

of infection.[4]

Cryostasis

The extraordinary medical prospects ahead of us have renewed interest in a proposal made

long ago: that the dying patient could be frozen, then stored at the temperature of liquid

nitrogen for decades or even centuries until the necessary medical technology to restore

health is developed. Called cryonics, this service is now available from several companies.

Because final proof that this will work must wait until after we have developed a medical


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technology based on the foundation of a mature nanotechnology, the procedure is

experimental. We cannot prove today that medical technology will (or will not) be able to

reverse freezing injury 100 years from now. But given the wonderful advances that we see

coming, it seems likely that we should be able to reverse freezing injury - especially when

that injury is minimized by the rapid introduction through the vascular system of

cryoprotectants and other chemicals to cushion the tissues against further injury.[4]

Disadvantages[3]

The initial design cost is very high.

The design of the nanorobot is a very complicated one.

Electrical systems can create stray fields which may activate bioelectric-based molecular

recognition systems in biology.

Electrical nanorobots are susceptible to electrical interference from external sources such

as rf or electric fields, EMP pulses, and stray fields from other in vivo electrical devices.

Hard to Interface, Customize and Design, Complex

Nanorobots can cause a brutal risk in the field of terrorism. The terrorism and anti-groups

can make use of nanorobots as a new form of torturing the communities as

nanotechnology also has the capability of destructing the human body at the molecular

level.

Privacy is the other potential risk involved with Nanorobots. As Nanorobots deals with

the designing of compact and minute devices, there are chances for more.[1]

Future footsteps of nanorobotics

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. Dr. Richard

Thompson, a former professor of ethics, has written about the ethical implications of

nanotechnology. He says the most important tool is communication, and that it's pivotal for

communities, medical organizations and the government to talk about nanotechnology now,


1414


while the industry is still in its infancy. Will we one day have thousands of microscopic

robots rushing around in our veins, making corrections and healing our cuts, bruises and

illnesses? With nanotechnology, it seems like anything is possible.

CONCLUSION

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.The nanorobots used in medicine are predicted to provide a wealth of

promise. When the severe side effects of the existing therapies are been considered, the

nanorobots are found to be more innovative, supportive to the treatment and diagnosis of vital

diseases. The respirocytes would be 236 times quicker when compared to normal red blood

cells. The nanorobotics are found to exhibit strong potential to diagnose and treat various

medical conditions like cancer, heart attack, diabetes, arteriosclerosis, kidney stones etc. The

nanorobot can allow us a personalized treatment, hence achieving high efficacy against many

diseases.

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NANOROBOTICS: MEDICINE OF THE FUTURE · Nanorobotics is an emerging, advanced and multidisciplinary field that calls for scientific and technical expertise of medical, pharmaceutical,

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