In 2007, productive nanosystems were defined as functional

nanoscale Nanotechnology is the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). At this scale, commonly known as the nanoscale, surface area and quantum mechanical effects become important in describing propertie ...

system A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...

s that make

atom Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished fr ...

ically-specified

structures A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

and

devices A device is usually a constructed tool. Device may also refer to: Technology Computing, electronics, mechanisms and telecommunication * Appliance, a device for a particular task * Computer, a computing device * Device file, an interface of a pe ...

under programmatic control, i.e., performing atomically precise manufacturing. As of 2015, such devices were only hypothetical, and productive nanosystems represented a more advanced approach among several to perform Atomically Precise Manufacturing. A workshop on Integrated Nanosystems for Atomically Precise Manufacturing was held by the

Department of Energy A ministry of energy or department of energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-rela ...

in 2015. Present-day technologies are limited in various ways. Large atomically precise structures (that is, virtually defect-free) do not exist.

Complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

3D nanoscale structures exist in the form of folded linear molecules such as

DNA origami DNA origami is the nanoscale folding of DNA to create arbitrary two- and three-dimensional shapes at the nanoscale. The specificity of the interactions between complementary base pairs make DNA a useful construction material, through design of i ...

and

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

s. As of 2018, it was also possible to build very small atomically precise structures using

scanning probe microscopy Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. SPM was founded in 1981, with the invention of the scanning tunneling microscope, an instrument for imaging ...

to construct molecules such as FeCO and

Triangulene Triangulene (also known as Clar's hydrocarbon) is the smallest triplet-ground-state polybenzenoid. It exists as a biradical with the chemical formula . It was first hypothesized by Czech chemist Erich Clar in 1953. Its first confirmed synthesi ...

, or to perform hydrogen depassivation lithography. But it is not yet possible to combine components in a systematic way to build larger, more complex systems. Principles of physics and examples from nature both suggest that it will be possible to extend atomically precise fabrication to more complex products of larger size, involving a wider range of materials. An example of progress in this direction would be Christian Schafmeister's work on bis-peptides.

Stages of progress in nanotechnology

In 2005,

Mihail Roco Mihail C. Roco is the founding chair of the US National Science and Technology Council subcommittee on Nanoscale Science, Engineering and Technology (NSET), and is Senior Advisor for Science and Engineering, including Nanotechnology, at the Nati ...

, one of the architects of the USA's National Nanotechnology Initiative, proposed four states of nanotechnology that seem to parallel the technical progress of the Industrial Revolution, of which productive nanosystems is the most advanced. 1. Passive nanostructures - nanoparticles and nanotubes that provide added strength, electrical and thermal conductivity, toughness, hydrophilic/phobic and/or other properties that emerge from their nanoscale structure. 2. Active

nanodevice Molecular machines are a class of molecules typically described as an assembly of a discrete number of molecular components intended to produce mechanical movements in response to specific stimuli, mimicking macromolecular devices such as switch ...

s - nanostructures that change states in order to transform energy, information, and/or to perform useful functions. There is some debate about whether or not state-of-the art integrated circuits qualify here, since they operate despite emergent nanoscale properties, not because of them. Therefore, the argument goes, they don't qualify as "novel" nanoscale properties, even though the devices themselves are between one and a hundred nanometers. 3. Complex

nanomachine Molecular machines are a class of molecules typically described as an assembly of a discrete number of molecular components intended to produce mechanical movements in response to specific stimuli, mimicking macromolecular devices such as switch ...

s - the assembly of different nanodevices into a nanosystem to accomplish a complex function. Some would argue that Zettl's machines fit in this category; others argue that modern microprocessors and

FPGA A field-programmable gate array (FPGA) is a type of configurable integrated circuit that can be repeatedly programmed after manufacturing. FPGAs are a subset of logic devices referred to as programmable logic devices (PLDs). They consist of a ...

s also fit. 4. Systems of nanosystems/Productive nanosystems - these will be complex nanosystems that produce atomically precise parts for other nanosystems, not necessarily using novel nanoscale-emergent properties, but well-understood fundamentals of manufacturing. Because of the discrete (i.e. atomic) nature of matter and the possibility of exponential growth, this stage is seen as the basis of another industrial revolution. There are currently many different approaches to building productive nanosystems: including top-down approaches like Patterned

atomic layer epitaxy Atomic layer epitaxy (ALE), more generally known as atomic layer deposition (ALD), is a specialized form of thin film growth (epitaxy) that typically deposit alternating monolayers of two elements onto a substrate. The crystal lattice structure a ...

and

Diamondoid In chemistry, diamondoids are generalizations of the carbon cage molecule known as adamantane (C10H16), the smallest unit cage structure of the diamond crystal lattice. Diamondoids also known as nanodiamonds or condensed adamantanes may include one ...

Mechanosynthesis Mechanosynthesis is a term for hypothetical chemical syntheses in which reaction outcomes are determined by the use of mechanical constraints to direct reactive molecules to specific molecular sites. There are presently no non-biological chemica ...

. There are also bottom-up approaches like

DNA Origami DNA origami is the nanoscale folding of DNA to create arbitrary two- and three-dimensional shapes at the nanoscale. The specificity of the interactions between complementary base pairs make DNA a useful construction material, through design of i ...

and Bis-peptide Synthesis."Molecular lego," Schafmeister, C. E.,

Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it, with more than 150 Nobel Pri ...

, 2007, 296, 76 A fifth step, info/bio/nano convergence, was added later by Roco. This is the convergence of the three most revolutionary technologies, since every living thing is made up of atoms and information.

References

{{reflist Nanotechnology

Stages of progress in nanotechnology

See also

References