Molecular Self Assembly

Molecular self-assembly is a concept of nanofabrication that involves designing molecules and supramolecular entities so that shape-complementarily causes them to aggregate into desired structures.

Instances of self assembly occur in biology , and in chemistry (such as the formation of more loosely bound supramolecular structures from groups of molecules). This may all seem like science fiction. In fact, brilliant theoretical physicist and Nobel laureate, Richard Feynman pointed the way to the science of nanotechnology with a talk in 1959 entitled "There's Plenty of Room at the Bottom," in which he suggested the possibility of controlling and assembling individual atoms and molecules on a one-by-one basis. { The Feynman Lectures on Physics: Feynman on Fundamentals: Energy and Motion }

Feynman's overall concept was that when engineers begin to precisely manipulate matter at the atomic level, we would finally achieve what alchemists sought in the Dark Ages — we would be able to take whatever raw atoms were available and rearrange their base components...electrons, neutrons, protons into a desired product.

Engines of Creation : The Coming Era of Nanotechnology Nanotechnology, or molecular technology, involves the manipulation of
individual atoms and molecules, something the human body already does.
In Engines of Creation , Drexler attempts to predict, justify, quantify,
and caution us about this important new field in engineering. His book
could have been the first and foremost discussion of this fascinating
subject

Technology and the Future

Complexity: The Emerging Science at the edge and order - Chaos

Hyper-Structured Molecules 3

Molecular Devices and Machines : A Journey into the Nanoworld

During his 1959 talk, Feynman went on to offer a $1,000 prize for the first electric motor small enough to be contained inside a 1/64 inch cube....the Foresight Institute has continued this tradition with an annual "Feynman Prize in Nanotechnology ($5,000) and the Feynman Grand Prize ($250,000).

Self-assembly has a number of advantages as a strategy:

Conceivably, it carries out many of the most difficult steps in nanofabrication--those involving atomic-level modification of structure--using the very highly developed techniques of synthetic chemistry.
It draws from the enormous wealth of examples in biology for inspiration: self-assembly is one of the most important strategies used in biology for the development of complex, functional structures.
It can incorporate biological structures directly as components in the fin Because it requires that the target structures be the thermodynamically most stable ones open to the system, it tends to produce structures that are relatively defect-free and self-healing." (George C. Whitesides - Dept of Chemistry at Harvard )

Folding and Self-Assembly of Biological Macromolecules

Self-Assembly in Supramolecular Systems

Self-Assembly Monolayer Structures of Lipids and Macromolecules at Interfaces

Modern Industrial Manufacturing manually produces products from their base components ...manually assembling theses components in the arrangements necessary to arrive at a finished product. This requires an intricate knowledge of the precise structure needed to arrive at a desired outcome/product... the ability to create the components within the required parameters ,the ability to place each component in a precise location so as not to jeopardize the final outcome.

Molecular self-assembly, {a/k/a programmable self-assembly} offers a theoretically more advanced and sound approach to producing products from base components.
While self-assembly theoretically can create a wide range of products , it has some inherent difficulties. Molecular Self-Assembly: Organic Versus Inorganic Approaches The exact set of components and interactions that will construct a given product can be difficult, if not impossible to determine

The statistical exploration of different possibilities provides the power of self-assembly, but can also make it difficult to settle on a single final structure, or to resist continual environmental aberrations/factors once assembled. The assembly process can become mired down in seemingly minuscule unconsidered/unrealized factors .

Proteins, the building blocks of DNA, have been harnessed with atomic level precision with the help of gene copying machines used by genome researchers. These mainly one-dimensional structures can be accurately grown in repetitive patterns according to rules designed into to their "seeds" IBM got into the nano-genome-protein action when it used the "lock and key" molecular recognition mechanism built into protein molecules, in an early biological application of nanotechnology. A MEMS "comb" had each tooth pretreated with a specific molecular "key," making it deflect in the presence of a single type of molecule. By measuring the deflection, IBM was able to detect DNA strands with only a single missing bond on a long protein chain, a feat impossible in real-time using conventional equipment.

Biology's creations are far smaller and vastly more complex than anything human engineering can produce . Recent biotech/nanotech advances have given us the tools necessary to consider engineering on the molecular level.

Research in DNA computation, launched by Len Adleman, has blazed a trail for experimental study of programmable biochemical reactions. This talk will focus on a single biochemical mechanism, the self-assembly of DNA structures, that is theoretically sufficient for Turing-universal computation. [ Biomedical Functions and Biotechnology of Natural and Artificial Polymers: Self-Assemblies, Hybrid Complexes and Biological Conjugates . ]

Polymers

Several different research groups have demonstrated that Brownian motion { random "mixing" of molecules in a liquid or gas} can exhibit auto-assembly if the parts are pretreated using IBM's lock-and-key application.

Green, Brown, & Probability and Brownian Motion on the Line Sandia National Labs has demonstrated that small molecules with the edges pretreated so that they can only bond together with the correct other parts, auto-assemble into atomically precise molecular building blocks

Researchers at the Fritz-Haber-Institut (Berlin) have created a new observational technique that can view surface catalytic reactions at the atomic scale

Researchers at the University of California at Santa Barbara, Tulane University New Orleans and Texas A&M University have found a means of creating defect-free, self-organized structures using the Langmuir-Blodgett technique [ An Introduction to Ultrathin Organic Films : From Langmuir--Blodgett to Self--Assembly . ]

ELECTRONICS
See also Carbon Nanotubes}

The most prominent Gains foreseeable via nanotech in electronics are enormous gains in device density -Reduced power consumption per transistor equivalent.

Self-assembly is a key element in the power consumption per transistor equivalent factor. Conventional semiconductor technology follows the " top-down" principle . Miniaturization, and productivity/efficiency primarily coming from improved lithography techniques, The molecular electronics approach is a "bottom-up" principle, starting from single molecular entities on a nanometer-scale to build information processing networks. That means, ultimate miniaturization of circuits will be reached if single molecules or atoms can be assembled into active devices that can switch, store and retrieve information. But all these devices would require wires {of fullerene nature ? } to link the components within an electronic device, theoretically realizable only with techniques envisioned in self-assembly.

Forked nanotubes - Another area of interest is "forked nanotubes" research has shown that Y shaped nanotubes amplify current, a necessary property for transistors. These nanotubes also allow current to flow in only one direction, meaning they could be used to convert alternating current to direct current. Transistors- the basic building blocks of most modern electronic devices including computers, have three points of contact. The forked nanotubes naturally have three terminals or points of contact.