10-09-2012, 07:02 PM
(This post was last modified: 10-09-2012, 07:25 PM by Administrator.)
DNA nanotechnology is broadly divided into two branches - Structural and Dynamic DNA nanotechnology.
What is Nanotechnology?
Nanotechnology is the field of science and technology which is concerned with studies of substances and systems at the atomic and molecular level which is generally 100 nanometers or smaller. It is a rapidly developing field, the societal implications of which are already evident. And DNA nanotechnology is branch which aims to create novel, controllable nanostructures out of DNA by using its unique molecular recognition properties and to achieve molecular self-assembly through the manipulation of DNA. It is a technology in which molecular components spontaneously organize into stable structures; this form of structures is induced by the physical and chemical properties of the components selected by the designers. These components have strands of nucleic acids such as DNA, which are constructed in nanoscale as a nucleic acid double helix has a diameter of 2 nm and a helical repeat length of 3.5 nm. The most important property of nucleic acids is that the binding between two nucleic acid strands depends on simple base pairing rule which helps in assembly of nucleic acid structures easy to control through nucleic acid design. This technology is used in manufacturing of various nanomedicine which is used for various treatments of various diseases. It is helping scientists and researchers in creating synthetic vaccines that could one day help treat and prevent many potentially fatal diseases like cancer, AIDS, Hepatitis, influenza, etc.
DNA nanotechnology has two broadly divided branches-
One is Structural DNA nanotechnology (SDN) which focuses on synthesizing and characterizing nucleic acid complexes and materials that assemble into a static, equilibrium end state. It uses unusual DNA motifs to build target shapes and arrangements and these are generated by reciprocal exchange of DNA backbones, leading to branched systems with many strands and multiple helical domains. The motifs may be combined by sticky ended cohesion, involving hydrogen bonding or covalent interactions and other forms of cohesion involves edge-sharing or paranemic interactions of double helices. Some of these motifs are simple branched junctions, but other motifs represent more complex strand topologies, with greater structural integrity. Other than this double crossover (DX), triple crossover (TX), paranemic crossover (PX) and parallelogram motifs are of great use. The sequences of these unusual motifs are designed by an algorithm that attempts to minimize sequence symmetry. A core goal of DNA nanotechnology is the self-assembly of periodic arrays. Micron-sized 2-dimensional DNA arrays from DX, TX and parallelogram motifs can be constructed. Patterns can be changed by changing and modifying the components after assembly. DNA molecules have been used successfully in DNA-based computation as molecular representations of Wang tiles, who’s self-assembly can be programmed to perform a calculation.
The other is Dynamic DNA nanotechnology which focuses on creating nucleic acid systems with designed dynamic functionalities related to their overall structures, such as computation and mechanical motion. Some complexes have a combination of both the subfields such as nucleic acid nanomechanical devices. DNA complexes change their structure with change in some stimulus, making them one form of nanorobotics which is designed to have a dynamic reconfiguration after the initial assembly. Various devices like circuits, catalytic amplifiers, autonomous molecular motors and reconfigurable nanostructures have been designed to use DNA strand-displacement reactions where two strands with partial or full complementarity hybridized by displacing one or more pre-hybridized strands. This mechanism allows for the kinetic control of reaction pathways and buffer is required. Some systems can change with the change in control strands thus forming multiple devices which independently operate in buffer solution. Cascades of strand displacement reactions can be used for either computational or structural purposes and are energetically favorable through the formation of new base pairs, and the entropy gain from disassembly reactions. These cascades are conducted under isothermal conditions for the assembly or computational process. They can also support catalytic functionality of the initiator species, where less than one equivalent of the initiator can cause the reaction to go to completion. These strand displacement complexes are used to form molecular logic gates capable of complex computation and these molecular computers use the concentrations of specific chemical species as signals. In nucleic acid strand displacement circuits the signal is the presence of nucleic acid strands that are released or consumed by binding and unbinding events to other strands in displacement complexes.
What is Nanotechnology?
Nanotechnology is the field of science and technology which is concerned with studies of substances and systems at the atomic and molecular level which is generally 100 nanometers or smaller. It is a rapidly developing field, the societal implications of which are already evident. And DNA nanotechnology is branch which aims to create novel, controllable nanostructures out of DNA by using its unique molecular recognition properties and to achieve molecular self-assembly through the manipulation of DNA. It is a technology in which molecular components spontaneously organize into stable structures; this form of structures is induced by the physical and chemical properties of the components selected by the designers. These components have strands of nucleic acids such as DNA, which are constructed in nanoscale as a nucleic acid double helix has a diameter of 2 nm and a helical repeat length of 3.5 nm. The most important property of nucleic acids is that the binding between two nucleic acid strands depends on simple base pairing rule which helps in assembly of nucleic acid structures easy to control through nucleic acid design. This technology is used in manufacturing of various nanomedicine which is used for various treatments of various diseases. It is helping scientists and researchers in creating synthetic vaccines that could one day help treat and prevent many potentially fatal diseases like cancer, AIDS, Hepatitis, influenza, etc.
DNA nanotechnology has two broadly divided branches-
One is Structural DNA nanotechnology (SDN) which focuses on synthesizing and characterizing nucleic acid complexes and materials that assemble into a static, equilibrium end state. It uses unusual DNA motifs to build target shapes and arrangements and these are generated by reciprocal exchange of DNA backbones, leading to branched systems with many strands and multiple helical domains. The motifs may be combined by sticky ended cohesion, involving hydrogen bonding or covalent interactions and other forms of cohesion involves edge-sharing or paranemic interactions of double helices. Some of these motifs are simple branched junctions, but other motifs represent more complex strand topologies, with greater structural integrity. Other than this double crossover (DX), triple crossover (TX), paranemic crossover (PX) and parallelogram motifs are of great use. The sequences of these unusual motifs are designed by an algorithm that attempts to minimize sequence symmetry. A core goal of DNA nanotechnology is the self-assembly of periodic arrays. Micron-sized 2-dimensional DNA arrays from DX, TX and parallelogram motifs can be constructed. Patterns can be changed by changing and modifying the components after assembly. DNA molecules have been used successfully in DNA-based computation as molecular representations of Wang tiles, who’s self-assembly can be programmed to perform a calculation.
The other is Dynamic DNA nanotechnology which focuses on creating nucleic acid systems with designed dynamic functionalities related to their overall structures, such as computation and mechanical motion. Some complexes have a combination of both the subfields such as nucleic acid nanomechanical devices. DNA complexes change their structure with change in some stimulus, making them one form of nanorobotics which is designed to have a dynamic reconfiguration after the initial assembly. Various devices like circuits, catalytic amplifiers, autonomous molecular motors and reconfigurable nanostructures have been designed to use DNA strand-displacement reactions where two strands with partial or full complementarity hybridized by displacing one or more pre-hybridized strands. This mechanism allows for the kinetic control of reaction pathways and buffer is required. Some systems can change with the change in control strands thus forming multiple devices which independently operate in buffer solution. Cascades of strand displacement reactions can be used for either computational or structural purposes and are energetically favorable through the formation of new base pairs, and the entropy gain from disassembly reactions. These cascades are conducted under isothermal conditions for the assembly or computational process. They can also support catalytic functionality of the initiator species, where less than one equivalent of the initiator can cause the reaction to go to completion. These strand displacement complexes are used to form molecular logic gates capable of complex computation and these molecular computers use the concentrations of specific chemical species as signals. In nucleic acid strand displacement circuits the signal is the presence of nucleic acid strands that are released or consumed by binding and unbinding events to other strands in displacement complexes.
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