Usage of nano technology for comm.

USAGE OF Nano-Technology FOR COMMUNICATION : 

USAGE OF Nano-Technology FOR COMMUNICATION

Contents: 

Contents Nanotechnology Introduction Nano-machine Nano-network Approaches for Nano-machines Development Top-Down Approach Bottom-Up Approach Bio-hybrid Approach Nano-machines Nano-machines Architecture Features of Nano-machines Roadmap Communication Among Nano-machines Dry Techniques Nano-wired Communication Wireless Optical Communication Wet Techniques Molecular Communication Applications Open issues in nano-network conclusion references

Nanotechnology: 

Nanotechnology Nanotechnology deals with creation of materials, structures, devices, systems, and architectures of any size by controlling matter at nanometer scale. Properties of materials (physical, chemical, electrical, magnetic, optical, mechanical, etc.) change when going from bulk to nano-scale . Therefore, it is not just about size alone but more about how to harness the change in properties and produce useful functionalities.

Introduction: 

Introduction Nanotechnology can best be defined as the development and practical applications of technological structures and devices on a nanometer scale, usually ranging from 0.1 to 100 nanometers. The prefix “nano-” means one billionth (10−9) of something, so nano-technology refers most generally to technology on the scale of a billionth of a meter.

History: 

History In his famous talk "There’s Plenty of Room at the Bottom” in 1959, novel physicist Richard Feynman pointed out first concepts in nanotechnology. In that speech, he proposed the "Top-Down” strategy for building complex nano-machinery. In 1981, K. E. Drexler descried a new ”Bottom-Up” approach involving molecular manipulation and molecular engineering in the context of building molecular machines and molecular devices with atomic precision. Research and advances in nanotechnology have been accelerated since the early 21st century.

Nano-machine : 

Nano-machine Nano-machines are biological or artificial created nano-scale devices or components that are capable of performing only very simple tasks of computation, sensing, or actuation in its very close environment. Molecular biological systems are themselves nano-machines; for instance, molecular motors are proteins or protein complexes that transform chemical energy. Nano-machines can be used as building blocks to perform more complex systems, such as nano-robots and nano-computing devices. Because of its small size, a single nano-machine generates a rather small force in the order of a few pico-Newton.

Nano-network : 

Nano-network Nano-networks will provide the infrastructure and mechanism to enable the communication between multiple nano-machines. Networked nano-machines may also cover larger areas, ranging from meters to kilometers, and expand the limited workspace of a single nano-machine which can only perform nano-scale objectives. This interaction between nano-machines can be carried out throughout several means: Nano-mechanical, Acoustic, Electromagnetic, and Chemical or Molecular.

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Nano-mechanical communication is not suitable in many scenarios because of the contact requirement between transmitter and receiver, and the need of a precise navigation system for their correct alignment. In acoustic communication the message is encoded in ultrasonic waves, while, in electromagnetic communication, information is transmitted through modulated electromagnetic waves. The main drawback for both of them is the size and current complexity of the transducer needed to establish that communication,, The output power of the nano-transceiver would not be enough to guarantee bidirectional communication. Consequently, it could be used to transmit information from micro-devices to nano-devices, but not on the opposite direction or between nano-machines. Molecular transceivers are able to react to specific molecules, and to release others in response to an internal command.

Approaches for Nano-machines Development : 

Approaches for Nano-machines Development Three different approaches for nano-machines development have been defined: Bottom- up approach method: That is, arranging smaller components into more complex assemblies. Top-down approach method: That is, creating smaller devices by using large ones to direct their assembly. Bio-hybrid Approach: That is, use of biomimetics to study the nature's way of performing different tasks.

Top-Down Approach : 

Top-Down Approach It is focused on the development of nano-scale machines by means of downscaling current existing devices at micro-scale. To build a nano-machine, the operator first directs a macro-scale machine to fabricate an exact copy of itself but four times smaller in size. After verification of its proper work, this reduced-scale machine would be used to build a copy of itself, another factor of four smaller but a factor of 16 tinier than the original one. This process of fabricating progressively smaller machines proceeds until a machine capable of manipulations at nano-scale is produced.

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The top-down approach is subject to drastic limitations, including a severe cost escalation when the components approach the nanometer dimension. As we go down in size, a number of problems arise which include scaling in proportion as well as materials stick together by the molecular attractions (Van Der Waals). Recently, progress is being made on top-down approach in a relatively new field known as Micro-Electro-Mechanical Systems (MEMS). Nano-machines as nano-electromechanical systems (NEMS) components are being developed using this approach, although manufacturing processes in this approach are still in an early stage.

Bottom-Up Approach : 

Bottom-Up Approach This approach starts from nano- or sub-nano-scale objects (namely atoms or molecules) to build up larger structures, using the chemical and physical forces that operate at nano-scale. A theoretical nano-machine build up atom-by-atom.

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The idea of an atom-by-atom bottom-up approach to nanotechnology is considered unrealistic for at least three well-grounded reasons: The fingers of a hypothetical manipulator arm should themselves be made out of atoms, which imply that they would be too fat to have control of the chemistry in the nanometer region. Such fingers would be also too sticky -the atoms of the manipulator hands would adhere to the atom that is being moved, so that it would be impossible to place it in the desired position. The continual shaking to which every nano-scale structure is subject because of collisions with the surrounding molecules would prevent precise nano-engineering.

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Later on, the idea that molecules could be much more convenient building blocks than atoms to construct nano-scale devices and machines arose. This idea was based on the following points: Molecules are stable species, whereas atoms are difficult to handle. Nature uses molecules (not atoms) to construct the great number and variety of nano-devices and nano-machines that sustain life. Most laboratory chemical processes deal with molecules (not atoms). Molecules are structures that already exhibit distinct shapes and carry device-related properties. Molecules can self-assemble or can be connected to make larger structures.

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A molecular device can be defined as an assembly of a discrete number of molecular components designed to achieve a specific function. Each molecular component performs a single act, while the entire supramolar assembly performs a more complex function. A molecular machine is a particular type of molecular device in which the component parts can display changes in their relative positions as a result of some external stimulus. The energy needed for the operation of a molecular device or molecular machine can be supplied in the form of – A chemical reagent, An absorbed photon, or Addition or subtraction of an electron. So far, many nano-machines, such as molecular differential gears and pumps, have been theoretically designed using individual molecules as building blocks. However, manufacturing technologies able to assemble nano-machines molecule-by-molecule do not exist yet.

Bio-hybrid Approach : 

Bio-hybrid Approach Several biological structures found in living organisms can be considered nano-machines. Biomimetics deals with the understanding, conceptualization and mimicking nature’s way of handling various problems and situations. In nano-scale, two levels in biomimetics are considered: Machine-nano-mimetic: It consists in the creation of artificial nano-machine components inspired by the equivalent machine components at nano-scale. Bio-nano-mimetic: Principle where biological entities, such as proteins and DNA, are used to create the nano-machine components.

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There are many complexities that are associated with using bio-components, but the advantages of using them are also quite considerable. These bio-components offer immense variety and functionality at a scale where creating a man made material with such capabilities would be extremely difficult. These bio-components have been perfected by nature through millions of years of evolution and hence they are very accurate and efficient. For instance, F1-ATPase is known to work at efficiencies which are close to 100%. Another significant advantage in protein-based bio-nano-components is the development and refinement over the last 30 years of tools and techniques enabling researchers to mutate proteins in almost any way imaginable. An excellent example of this approach is the use of zinc to control F1-ATPase, which is able to rotate a nano-propeller in the presence of ATP.

Nano-machines Architecture : 

Nano-machines Architecture Functional architecture mapping between nano machines of a nano robot, and nano machines found in cells.

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Control Unit: It is aimed at executing the instructions to perform the intended tasks controlling all the other nano machine’s components. It could include a storage unit, in which the information of the nano machine is saved. Communication Unit: It consists of a transceiver able to transmit and receive messages (molecules) at nano-level. Reproduction Unit: The function of this unit is to fabricate each component of the nano-machine using external elements, and then assemble them to replicate it. This unit is provided with all the instructions needed to realize this task. Power Unit: This unit is aimed at powering all the components of the nano-machine by getting energy from external sources such as light or temperature, and stores it for a later distribution and consumption. Sensors and Actuators: These components act as an interface between the environment and the nano-machine. Several sensors and/or actuators can be included in a nano-machine, e.g., temperature sensors, chemical sensors, clamps, pumps, motor or locomotion mechanisms

Features of Nano-machines : 

Features of Nano-machines Self-content: Nano-machines will have a set of instructions to realize specific tasks, embedded in their molecular structure. Self-assembly and self-replication enable assemblage at nano-scale and nano-maintenance, without external intervention. Locomotion enables nano-machines to move. Communication between nano machines is required to realize more complex tasks in a cooperative manner, and enable decentralization and distributive intelligence. “Nano” to “macro” world interface architecture providing instant access to nano-machines, its control and maintenance.

Nano-machine vs Cells: 

Nano-machine vs Cells Multitasking: A cell can be doing several different actions at the same time. On the one hand, it can take nutrients; convert them into energy, reproduce, breath, etc. On the other, while doing these vital functions, it can be sampling the environment or signaling other cells in the nearby. Thus nano-machines, as well as cells, should be understood as complex and complete systems. multiple-interface devices: Cells have hundreds, or even thousands, of receivers. A single cell is able to communicate using different channel access techniques: gap junctions, ligand-receptors, molecular motors. Specific and highly sensitive signal transducing mechanisms: The receptors bind the signal molecule, amplify the signal, integrate it with input from other receptors, and transmit it into the cell. If the signal persists, receptor desensitization reduces or ends the response.

Continue………..: 

Continue……….. Four features of signal-transducing systems: (a) Specificity, (b) Amplification, (c) Desensitization, and (d) Integration

Roadmap: 

Roadmap The roadmap for the Development of bio-nano Robotic systems for Future applications

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The roadmap progresses through the following main steps: The first research area is in determining the structure, behavior and properties of basic bio-nano-components. The next step is combining these components into complex assemblies. By the beginning of this phase a “library of bio-nano-components” will be developed, which will include actuation, energy source, sensory, signaling etc. With the individual bio-nano-robots capable of basic functions, concepts of co-operative behavior and distributed intelligence need to be developed, to enable them to collaborate with one another. Again, it is planed to follow nature’s path, mimicking the various colonies of insects and animals, and transforming principles learned to our domain. The next step in nano-robotic designing would see the emergence of automatic fabrication methodologies.

Communication among Nano-machines : 

Communication among Nano-machines Multiple nano-machines can be interconnected to work collaboratively and in a distributed manner to perform complex tasks such as sensing, computation, or actuation. The interconnection and communication of functional components at nano-scale (nano-network) take place by the means of following two techniques: Dry techniques. Wet techniques.

Dry Techniques : 

Dry Techniques Dry techniques refer to all of the nanotechnologies that deal with the study of fabrication of structures in carbon, silicon and other inorganic materials. It is usually aimed at building nano-scale structures, by scaling down the current micro scale technology, that then need to be assembled on a chip. Nano-wires and nano-tubes are good examples of such techniques. Nano-wired communications. Wireless optical communications.

Nano-wired Communication : 

Nano-wired Communication A nano-wire is a structure that has a diameter constrained to tens of nanometers or less and an unconstrained length. Typical nano-wires exhibit aspect ratios (length-to-width ratio) grater than 1000. A variety of organic (e.g. DNA) and inorganic wires (e.g. silicon nano-wires and carbon nano-tubes) have been fabricated. Nano-wires could be used to link tiny components into extremely small circuits. The size scale of nano-scale metallic, semiconducting wires with high aspect ratio, as compared with fabricated (CMOS) structure sizes.

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Nano-wire and carbon nano-tube networks have several advantages in comparison with other structures, such as thin films : Conductance: The conductivity of the wires is large; the larger the nano-wire conductivity, the better the network conductance. Transparency: A network of highly one dimensional wire has very elevated transparency (approaching 100% for truly one dimensional wire). Flexibility: A random network of wires has significantly higher flexibility that a film of comparable surface coverage. Fault Tolerance: Breaking a conducting path leaves many others open. The electron pathways will be rearranged. The Individual Components: The ability to make highly perfect wires with quality superior than that of thin films is retained in the random nano-nets. Due to their small size, nano-tubes can reach deep into their environment without affecting their natural behavior. Individual nano-tubes can be used to construct a network of sensing elements with a greater depth and coverage than today’s sensor networks. Unfortunately, networking such a collection of sensors using current techniques negates the advantages of CNT size.

Wireless Optical Communication: 

Wireless Optical Communication The communication is achieved through the emission of photons from a properly excited molecule, which are captured by a predisposed receiver. Such kind of communication is suggested by plasmonics , which studies the properties of collective electronic excitations in thin films ( surface plasmons ). A Plasmon is a quasi-particle resulting from the quantization of plasma oscillations, just as photons and phonons are quantization of light and sound waves, respectively. One can think of a plasmon as a sphere comprised of many discrete, evenly-spaced positive charges that can be approximated as a positive charge distribution, which at the same time is surrounded by a negative charge distribution consisting of a free electron cloud hovering just on top of the positive charge distribution, but not in contact. They are basically vibrational modes of the electron gas density, oscillating about the metallic ion cores, often at optical frequencies.

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Surface plasmons capture specific wavelengths of light and convert an amount of electrical energy back into light that is reflected away. In other words, plasmons couple with a photon to create a third quasi-particle called a plasma polariton. This polariton propagates along the surface of the metal until it decays.

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Surface Plasmon can be excited by both electrons and photons. If light frequency is lower than the plasma’s, light is reflected, because the electrons in the metal screen the electric field of the light. Whereas if, light frequency is higher than that of plasma; light is transmitted, because the electrons cannot respond fast enough to screen it. Plasmons have been considered as a means of transmitting information on computer chips, since they can support much higher frequencies (100 THz range). Surface plasmons can be described by Maxwell’s equations if only if the electron mean free path in the metal is much shorter than the plasmons wavelength, which is usually fulfilled at optical frequencies. The main drawback in optical molecular communication is that classical mechanic laws do usually fail, due to quantum effects.

Wet Techniques: Molecular Communication: 

Wet Techniques: Molecular Communication Wet techniques refer to the study of biological systems that usually operate in aqueous environment, such as DNA-based systems, etc. (molecular communication). Molecular communication is a new communication paradigm. It does not use electromagnetic waves but uses molecules to transmit the information. Molecular communication process

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Key components of above communication system include a transmitter, a receiver, and a propagation system to perform followings: Encoding: The transmitter encodes information onto molecules (called information molecules ). Transmission: The transmitter inserts the message into the medium by releasing the encoded information molecules to the environment or by attaching them to molecular carriers. Propagation: Information molecules propagate from the transmitter to the receiver. Reception: Information molecules are detected or unloaded from the carriers at a receiver. Decoding/Reaction: Upon receiving the information molecules, the receiver decodes the molecular message into useful information such as biochemical reaction, data storing, actuation commands... Molecular communication provides means for biological and artificially-created nano-machines to communicate over short and long distances where short-range is understood as the communication process that takes place in the range from nm to few mm, whereas long-range refer to the communication process that take place in the range from mm up to km.

Short-Range Communication: 

Short-Range Communication Molecular motors are proteins or protein complexes that transform chemical energy into mechanical work at a nano-scale. These protein motors can transport a data packet (molecule) from the transmitter to the receiver. On the transmitter side, the information molecules are loaded on molecular motors, which transport the information along the microtubules to the receiver. The packets can be encapsulated in vesicles, which have a twofold objective: It allows enhancing the compatibility between the information molecule and the molecular motor, enabling the use of diverse types of molecules as information packets. The encapsulation protects the information molecules avoiding them to react with antagonistic receptors present in the medium. Using Molecular Motors:

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The propagation of molecular motors along a microtubule is unidirectional. The polarity of the microtubule indicates the movement direction of specific molecular motors. The concept of bio-inspired communication through molecular motors can be summarized as follows: For a given network topology, there exists rail molecules (micro-tubules) establishing connections among several nano-machines. When a cell needs to transmit a specific molecule (or even a vesicle), it releases it onto a molecular motor. Moving along a pre-established path, the molecular motor will reach the destination. The molecule (or vesicle) will either bind to the receiver or be absorbed through a gap junction. System components in molecular motors communication systems .

Using Molecular Signals:: 

Using Molecular Signals: In molecular signaling based communications, the information is transmitted by varying a given concentration of molecules (signals) according to the information that needs to be propagated, Thus molecule concentration level is considered as the carrier. This carrier may be modulated either: In frequency: by changing the rate of the molecule concentration (calcium signaling) In amplitude: by changing the number of molecules per unit volume. Propagation of information can be performed either by Indirect Access, or Direct Access.

Signal propagation in calcium signaling communication systems by (a) gap junctions signal forwarding and (b) by diffusion.: 

Signal propagation in calcium signaling communication systems by (a) gap junctions signal forwarding and (b) by diffusion.

Indirect Access:: 

Indirect Access: Here cells or nano-machines are deployed separately without any physical contact; the bio-inspired approach of the communication scheme can be described as: Nano-machines and particles suspended in a liquid or gaseous medium, move randomly according to Brownian dynamics. When a cell or a nano-machine has to transmit some information it releases a specific type of molecules, which may range in the order of hundreds or even thousands, into the medium. At that moment, the concentration of molecules around the cell increases abruptly. Due to molecular diffusion, these molecules will travel through the medium dispersing themselves randomly. During this propagation phase, other particles in the medium following Brownian dynamics can collide, or even block the movement of these molecules due to noise and interference coming from other molecules being released at the same time. These molecules may finally reach the receptors, which can be also in the order of hundreds or even thousands per cell or nano-machine, located in the cell membrane. These molecules may or may not bind to the receptors, with different affinities. The reaction of a cell will depend on the type of molecule received and different stimulus. Before a cell can transmit again the same molecule, there is an implicit waiting time related to the detaching phase of the molecules from the receivers.

Direct Access:: 

Direct Access: When cells or nano-machines are physically located in direct contact, then molecular signals propagate through gap junctions. A gap junction is a specialized intercellular connection which directly connects the cytoplasm of two cells, allowing various molecules and ions to pass freely between cells. Two different phases within the communication process can be identified: Approximation phase: Here a cell/nano-machine physically reaches its target Transmission phase: Here following communication process starts: Two or more cells (nano-machines), being in physical contact, exchange molecules using gap junctions. One cell can be in contact with different cells and have different gap junctions open simultaneously. While being in contact, ions or molecules will propagate from one cell to another, by following the principles of molecular diffusion resulting from the difference of concentration of a specific molecule type.

Long-Range Communication using Pheromones: : 

Long-Range Communication using Pheromones: Pheromones are encoded molecular messages that are released into the medium and may only be detected by selective nano-machines according to receptor-binding mechanisms. The communication process can be briefly summarized as follows: When a cell or a nano-machine has to transmit some information it releases a specific type of pheromones, into either an aqueous or a gaseous medium. At that moment, the concentration of molecules around the cell increases abruptly. Due to molecular diffusion, pheromones will travel through the medium dispersing them randomly. During this propagation phase, other particles in the medium following Brownian dynamics can collide, or even block the movement of these molecules due to noise and interference. In this scenario physical obstacles should be also taken into account. Moreover, propagation of the information can also be affected by several other factors such as medium flow, temperature, and dispersion, which can also be considered as sources of noise. Pheromones may finally reach the receptors which can be located up to several kilometers from the source nano-machines. Also in this case, pheromones may or may not bind to the receptors and with different affinities. The reaction of a cell will depend on the type of molecule received and different stimulus.

Conceptual diagram of a pheromonal communication. Biological models provide a useful example of molecular communication scalability: 

Conceptual diagram of a pheromonal communication. Biological models provide a useful example of molecular communication scalability Nano-networks based on pheromonal communication offers a unique opportunity to combine the advantages of nano-scale and long range communication ( “nano” and “macro” world), since information is encoded at nano-scale, although transmitter and receiver nano-machines can be considered as macro-systems.

Differences with traditional communication networks : 

Differences with traditional communication networks 1. While in traditional communication networks, the information is encoded in electromagnetic, acoustic or optical signals; in nano-networks molecules (molecular communication) and bio-polymers are used to represent the information/message. Coding techniques: (a) Concentration encoding; (b) Molecular encoding. For simplicity, both are binary communication; (c) DNA-encoding.

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2. The propagation speed of signals used in traditional communication networks is much faster than the propagation of molecular messages. 3. In traditional communication networks, noise is described as an undesired signal overlapped with the signals transporting the information. In nano-networks, according to the coding techniques, two different types of noise can affect the messages. First, as occurs in traditional communication systems, noise can be overlapped with molecular signals such as concentration level of other molecules. At the same time, in nano-networks, noise can also be understood as an undesired reaction occurring between information molecules and other molecules present in the environment, which can modify the structure of the information molecules. 4. Text, voice and video are usually transmitted over traditional communication networks. By contrast, in nano-networks the transmitted information is more related to phenomena, chemical states and processes. 5. In nano-networks, most of the processes are chemically driven resulting in low power consumption. In traditional communication networks the communication processes consume electrical power that is obtained from batteries or from external sources such as electromagnetic induction.

Open issues in nano-network: 

Open issues in nano-network Most of the existing communication networks knowledge is not suitable for nano-networks due to their particular features. Nano-networks require innovative networking solutions according to the characteristics of the network components and the molecular communication processes. There is still a lot of work to do in order to develop efficient molecular communication techniques, such as Determining the average speed of different bio-inspired molecular motors in different aqueous media, Obtain a propagation model and a channel capacity expression for each type of molecular communications, Characterizing and identifying different types of pheromones, etc.

Conclusion : 

Conclusion A Continuum of Opportunity for Nanotechnology in the Life Sciences. Nanotechnology is a cutting edge investigation area that has come out with new and unlimited applications. The recent explosion of research in this field, combined with important discoveries in molecular biology have created a new interest in bio-nano-robotic communication.

This presentation…….: 

This presentation……. This presentation provides a general theoretical understanding of nano-networks and their multiple possibilities. It describes some basic concepts of architectures that compose nanotechnology topologies, as well as possible designs for the tiny nano-network components, the nano-machines. Molecular communication applied to nano-networks presents indeed extremely appealing features in terms of energy consumption, reliability and robustness. Nevertheless, it remains to understand the impact of the extremely slow propagation of molecules and the highly variable environments. Anyhow, innovative results are expected in terms of novel communications and networking strategies for networked nano-scale systems.

References: 

References “Modeling the Molecular Communication Nano-networks” by Neus Roca Lacasa (January 13, 2009). Nano-networks: A new frontier in communication by Ian F. Alkyldiz , Josep Miquel Jornet & Massimiliano Pierobon (November, 2011). www.ece.gatech.edu/research/labs/bwn/monaco/index.html www.ece.gatech.edu/research/labs/bwn/monaco/projectdescription.html