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A molecular assembler, as defined by
K. Eric Drexler Kim Eric Drexler (born April 25, 1955) is an American engineer best known for studies of the potential of molecular nanotechnology (MNT), from the 1970s and 1980s. His 1991 doctoral thesis at Massachusetts Institute of Technology was revised and ...
, is a "proposed device able to guide
chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking ...
s by positioning reactive molecules with atomic precision". A molecular assembler is a kind of
molecular machine A molecular machine, nanite, or nanomachine is a molecular component that produces quasi-mechanical movements (output) in response to specific stimuli (input). In cellular biology, macromolecular machines frequently perform tasks essential for l ...
. Some biological molecules such as
ribosome Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to fo ...
s fit this definition. This is because they receive instructions from
messenger RNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein. mRNA is created during the ...
and then assemble specific sequences of
amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
to construct
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
molecules. However, the term "molecular assembler" usually refers to theoretical human-made devices. Beginning in 2007, the British
Engineering and Physical Sciences Research Council The Engineering and Physical Sciences Research Council (EPSRC) is a British Research Council that provides government funding for grants to undertake research and postgraduate degrees in engineering and the physical sciences, mainly to univers ...
has funded development of
ribosome Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to fo ...
-like molecular assemblers. Clearly, molecular assemblers are possible in this limited sense. A technology roadmap project, led by the
Battelle Memorial Institute Battelle Memorial Institute (more widely known as simply Battelle) is a private nonprofit applied science and technology development company headquartered in Columbus, Ohio. Battelle is a charitable trust organized as a nonprofit corporation und ...
and hosted by several U.S. National Laboratories has explored a range of atomically precise fabrication technologies, including both early-generation and longer-term prospects for programmable molecular assembly; the report was released in December, 2007. In 2008, the Engineering and Physical Sciences Research Council provided funding of £1.5 million over six years (£1,942,235.57, $2,693,808.00 in 2021) for research working towards mechanized
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 ...
, in partnership with the Institute for Molecular Manufacturing, amongst others. Likewise, the term "molecular assembler" has been used in
science fiction Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel uni ...
and
popular culture Popular culture (also called mass culture or pop culture) is generally recognized by members of a society as a set of practices, beliefs, artistic output (also known as, popular art or mass art) and objects that are dominant or prevalent in a ...
to refer to a wide range of fantastic atom-manipulating nanomachines. Much of the controversy regarding "molecular assemblers" results from the confusion in the use of the name for both technical concepts and popular fantasies. In 1992, Drexler introduced the related but better-understood term "molecular manufacturing", which he defined as the programmed "
chemical synthesis As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In mod ...
of complex structures by mechanically positioning reactive molecules, not by manipulating individual atoms". This article mostly discusses "molecular assemblers" in the popular sense. These include hypothetical machines that manipulate individual atoms and machines with organism-like
self-replicating Self-replication is any behavior of a dynamical system that yields construction of an identical or similar copy of itself. Biological cells, given suitable environments, reproduce by cell division. During cell division, DNA is replicated and ca ...
abilities, mobility, ability to consume food, and so forth. These are quite different from devices that merely (as defined above) "guide chemical reactions by positioning reactive molecules with atomic precision". Because synthetic molecular assemblers have never been constructed and because of the confusion regarding the meaning of the term, there has been much controversy as to whether "molecular assemblers" are possible or simply science fiction. Confusion and controversy also stem from their classification as
nanotechnology Nanotechnology, also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal ...
, which is an active area of laboratory research which has already been applied to the production of real products; however, there had been, until recently, no research efforts into the actual construction of "molecular assemblers". Nonetheless, a 2013 paper by David Leigh's group, published in the journal ''
Science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence ...
'', details a new method of synthesizing a
peptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. ...
in a sequence-specific manner by using an artificial molecular machine that is guided by a molecular strand. This functions in the same way as a ribosome building proteins by assembling amino acids according to a messenger RNA blueprint. The structure of the machine is based on a rotaxane, which is a molecular ring sliding along a molecular axle. The ring carries a
thiolate In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl grou ...
group, which removes amino acids in sequence from the axle, transferring them to a peptide assembly site. In 2018, the same group published a more advanced version of this concept in which the molecular ring shuttles along a polymeric track to assemble an
oligopeptide An oligopeptide, often just called peptide ('' oligo-'', "a few"), consists of two to twenty amino acids and can include dipeptides, tripeptides, tetrapeptides, and pentapeptides. Some of the major classes of naturally occurring oligopeptides in ...
that can fold into an
α-helix The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ...
that can perform the
enantioselective In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical an ...
epoxidation In organic chemistry, an epoxide is a cyclic ether () with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale ...
of a
chalcone Chalcone is the organic compound C6H5C(O)CH=CHC6H5. It is an α,β-unsaturated ketone. A variety of important biological compounds are known collectively as chalcones or chalconoids. Chemical properties Chalcones have two absorption maxima at ...
derivative (in a way reminiscent to the ribosome assembling an
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
). In another paper published in ''Science'' in March 2015, chemists at the
University of Illinois The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the Uni ...
report a platform that automates the synthesis of 14 classes of
small molecule Within the fields of molecular biology and pharmacology, a small molecule or micromolecule is a low molecular weight (≤ 1000 daltons) organic compound that may regulate a biological process, with a size on the order of 1 nm. Many drugs ...
s, with thousands of compatible building blocks. In 2017, David Leigh's group reported a molecular robot that could be programmed to construct any one of four different
stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...
s of a molecular product by using a nanomechanical robotic arm to move a molecular substrate between different reactive sites of an artificial molecular machine. An accompanying News and Views article, titled ‘A molecular assembler’, outlined the operation of the molecular robot as effectively a prototypical molecular assembler.


Nanofactories

A nanofactory is a proposed system in which
nanomachines A molecular machine, nanite, or nanomachine is a molecular component that produces quasi-mechanical movements (output) in response to specific stimuli (input). In cellular biology, macromolecular machines frequently perform tasks essential for l ...
(resembling molecular assemblers, or industrial robot arms) would combine reactive molecules via
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 ...
to build larger atomically precise parts. These, in turn, would be assembled by positioning mechanisms of assorted sizes to build macroscopic (visible) but still atomically-precise products. A typical nanofactory would fit in a desktop box, in the vision of
K. Eric Drexler Kim Eric Drexler (born April 25, 1955) is an American engineer best known for studies of the potential of molecular nanotechnology (MNT), from the 1970s and 1980s. His 1991 doctoral thesis at Massachusetts Institute of Technology was revised and ...
published in ''Nanosystems: Molecular Machinery, Manufacturing and Computation'' (1992), a notable work of " exploratory engineering". During the 1990s, others have extended the nanofactory concept, including an analysis of nanofactory convergent assembly by Ralph Merkle, a systems design of a replicating nanofactory architecture by J. Storrs Hall, Forrest Bishop's "Universal Assembler", the patented exponential assembly process by Zyvex, and a top-level systems design for a 'primitive nanofactory' by Chris Phoenix (director of research at the Center for Responsible Nanotechnology). All of these nanofactory designs (and more) are summarized in Chapter 4 of ''Kinematic Self-Replicating Machines'' (2004) by
Robert Freitas Robert A. Freitas Jr. (born 1952) is an American nanotechnologist. Career In 1974, Freitas earned a bachelor's degree in both physics and psychology from Harvey Mudd College, and in 1978, he received a Juris Doctor (J.D.) degree from Santa Clara ...
and Ralph Merkle. The Nanofactory Collaboration, founded by Freitas and 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 positionally-controlled
diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, b ...
mechanosynthesis and diamondoid nanofactory development. In 2005, a
computer-animated Computer animation is the process used for digitally generating animations. The more general term computer-generated imagery (CGI) encompasses both static scenes (still images) and dynamic images (moving images), while computer animation refer ...
short film A short film is any motion picture that is short enough in running time not to be considered a feature film. The Academy of Motion Picture Arts and Sciences defines a short film as "an original motion picture that has a running time of 40 minutes ...
of the nanofactory concept was produced by John Burch, in collaboration with Drexler. Such visions have been the subject of much debate, on several intellectual levels. No one has discovered an insurmountable problem with the underlying theories and no one has proved that the theories can be translated into practice. However, the debate continues, with some of it being summarized in the
molecular nanotechnology Molecular nanotechnology (MNT) is a technology based on the ability to build structures to complex, atomic specifications by means of mechanosynthesis. This is distinct from nanoscale materials. Based on Richard Feynman's vision of miniatur ...
article. If nanofactories could be built, severe disruption to the
world economy The world economy or global economy is the economy of all humans of the world, referring to the global economic system, which includes all economic activities which are conducted both within and between nations, including production, consumptio ...
would be one of many possible negative impacts, though it could be argued that this disruption would have little negative effect, if everyone had such nanofactories. Great benefits also would be anticipated. Various works of
science fiction Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel uni ...
have explored these and similar concepts. The potential for such devices was part of the mandate of a major UK study led by
mechanical engineering Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, ...
professor Dame
Ann Dowling Dame Ann Patricia Dowling (born 15 July 1952) is a British mechanical engineer who researches combustion, acoustics and vibration, focusing on efficient, low-emission combustion and reduced road vehicle and aircraft noise. Dowling is a Deputy ...
.


Self-replication

"Molecular assemblers" have been confused with self-replicating machines. To produce a practical quantity of a desired product, the nanoscale size of a typical science fiction universal molecular assembler requires an extremely large number of such devices. However, a single such theoretical molecular assembler might be programmed to self-replicate, constructing many copies of itself. This would allow an exponential rate of production. Then, after sufficient quantities of the molecular assemblers were available, they would then be re-programmed for production of the desired product. However, if self-replication of molecular assemblers were not restrained then it might lead to competition with naturally occurring organisms. This has been called
ecophagy Ecophagy is a term coined by Robert Freitas that means the literal consumption of an ecosystem. It derives from the Greek "οἶκος" (), which refers to a "house" or "household", and the Greek "φαγεῖν" (), "to eat". Freitas used the te ...
or the
grey goo Gray goo (also spelled as grey goo) is a hypothetical global catastrophic scenario involving molecular nanotechnology in which out-of-control self-replicating machines consume all biomass on Earth while building many more of themselves, a sce ...
problem. One method of building molecular assemblers is to mimic evolutionary processes employed by biological systems. Biological evolution proceeds by random variation combined with culling of the less-successful variants and reproduction of the more-successful variants. Production of complex molecular assemblers might be evolved from simpler systems since "A
complex system A complex system is a system composed of many components which may interact with each other. Examples of complex systems are Earth's global climate, organisms, the human brain, infrastructure such as power grid, transportation or communication sy ...
that works is invariably found to have evolved from a simple system that worked. . . . A complex system designed from scratch never works and can not be patched up to make it work. You have to start over, beginning with a system that works." Gall, John, (1986) Systemantics: How Systems Really Work and How They Fail, 2nd ed. Ann Arbor, MI : The General Systemantics Press. However, most published safety guidelines include "recommendations against developing ... replicator designs which permit surviving mutation or undergoing evolution". Most assembler designs keep the "source code" external to the physical assembler. At each step of a manufacturing process, that step is read from an ordinary computer file and "broadcast" to all the assemblers. If any assembler gets out of range of that computer, or when the link between that computer and the assemblers is broken, or when that computer is unplugged, the assemblers stop replicating. Such a "broadcast architecture" is one of the safety features recommended by the "Foresight Guidelines on Molecular Nanotechnology", and a map of the 137-dimensional replicator design space recently published by Freitas and Merkle provides numerous practical methods by which replicators can be safely controlled by good design.


Drexler and Smalley debate

One of the most outspoken critics of some concepts of "molecular assemblers" was Professor Richard Smalley (1943–2005) who won the
Nobel prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...
for his contributions to the field of
nanotechnology Nanotechnology, also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal ...
. Smalley believed that such assemblers were not physically possible and introduced scientific objections to them. His two principal technical objections were termed the "fat fingers problem" and the "sticky fingers problem". He believed these would exclude the possibility of "molecular assemblers" that worked by precision picking and placing of individual atoms. Drexler and coworkers responded to these two issues in a 2001 publication. Smalley also believed that Drexler's speculations about apocalyptic dangers of self-replicating machines that have been equated with "molecular assemblers" would threaten the public support for development of nanotechnology. To address the debate between Drexler and Smalley regarding molecular assemblers ''
Chemical & Engineering News ''Chemical & Engineering News'' (''C&EN'') is a weekly news magazine published by the American Chemical Society, providing professional and technical news and analysis in the fields of chemistry and chemical engineering.


Regulation

Speculation on the power of systems that have been called "molecular assemblers" has sparked a wider political discussion on the implication of nanotechnology. This is in part due to the fact that nanotechnology is a very broad term and could include "molecular assemblers". Discussion of the possible implications of fantastic molecular assemblers has prompted calls for regulation of current and future nanotechnology. There are very real concerns with the potential health and ecological impact of nanotechnology that is being integrated in manufactured products.
Greenpeace Greenpeace is an independent global campaigning network, founded in Canada in 1971 by Irving Stowe and Dorothy Stowe, immigrant environmental activists from the United States. Greenpeace states its goal is to "ensure the ability of the Earth t ...
for instance commissioned a report concerning nanotechnology in which they express concern into the toxicity of nanomaterials that have been introduced in the environment. However, it makes only passing references to "assembler" technology. The UK
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
and
Royal Academy of Engineering The Royal Academy of Engineering (RAEng) is the United Kingdom's national academy of engineering. The Academy was founded in June 1976 as the Fellowship of Engineering with support from Prince Philip, Duke of Edinburgh, who became the first senior ...
also commissioned a report entitled "Nanoscience and nanotechnologies: opportunities and uncertainties" regarding the larger social and ecological implications of nanotechnology. This report does not discuss the threat posed by potential so-called "molecular assemblers".


Formal scientific review

In 2006, the
U.S. National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Natio ...
released the report of a study of molecular manufacturing as part of a longer report, ''A Matter of Size: Triennial Review of the National Nanotechnology Initiative'' The study committee reviewed the technical content of ''Nanosystems'', and in its conclusion states that no current theoretical analysis can be considered definitive regarding several questions of potential system performance, and that optimal paths for implementing high-performance systems cannot be predicted with confidence. It recommends experimental research to advance knowledge in this area: :"Although theoretical calculations can be made today, the eventually attainable range of chemical reaction cycles, error rates, speed of operation, and thermodynamic efficiencies of such bottom-up manufacturing systems cannot be reliably predicted at this time. Thus, the eventually attainable perfection and complexity of manufactured products, while they can be calculated in theory, cannot be predicted with confidence. Finally, the optimum research paths that might lead to systems which greatly exceed the thermodynamic efficiencies and other capabilities of biological systems cannot be reliably predicted at this time. Research funding that is based on the ability of investigators to produce experimental demonstrations that link to abstract models and guide long-term vision is most appropriate to achieve this goal."


Grey goo

One potential scenario that has been envisioned is out-of-control self-replicating molecular assemblers in the form of
grey goo Gray goo (also spelled as grey goo) is a hypothetical global catastrophic scenario involving molecular nanotechnology in which out-of-control self-replicating machines consume all biomass on Earth while building many more of themselves, a sce ...
which consumes carbon to continue its replication. If unchecked, such mechanical replication could potentially consume whole
ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...
s or the whole Earth (
ecophagy Ecophagy is a term coined by Robert Freitas that means the literal consumption of an ecosystem. It derives from the Greek "οἶκος" (), which refers to a "house" or "household", and the Greek "φαγεῖν" (), "to eat". Freitas used the te ...
), or it could simply outcompete natural lifeforms for necessary resources such as
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...
, ATP, or UV light (which some
nanomotor A nanomotor is a molecular or nanoscale device capable of converting energy into movement. It can typically generate forces on the order of piconewtons. While nanoparticles have been utilized by artists for centuries, such as in the famous Lycu ...
examples run on). However, the
ecophagy Ecophagy is a term coined by Robert Freitas that means the literal consumption of an ecosystem. It derives from the Greek "οἶκος" (), which refers to a "house" or "household", and the Greek "φαγεῖν" (), "to eat". Freitas used the te ...
and 'grey goo' scenarios, like synthetic molecular assemblers, are based upon still-hypothetical technologies that have not yet been demonstrated experimentally.


See also

*
Nanotechnology Nanotechnology, also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal ...
*
Molecular machine A molecular machine, nanite, or nanomachine is a molecular component that produces quasi-mechanical movements (output) in response to specific stimuli (input). In cellular biology, macromolecular machines frequently perform tasks essential for l ...
*
Bioethics Bioethics is both a field of study and professional practice, interested in ethical issues related to health (primarily focused on the human, but also increasingly includes animal ethics), including those emerging from advances in biology, me ...
*
Biosafety Biosafety is the prevention of large-scale loss of biological integrity, focusing both on ecology and human health. These prevention mechanisms include conduction of regular reviews of the biosafety in laboratory settings, as well as strict guide ...
*
Biosecurity Biosecurity refers to measures aimed at preventing the introduction and/or spread of harmful organisms (e.g. viruses, bacteria, etc.) to animals and plants in order to minimize the risk of transmission of infectious disease. In agriculture, ...
*
Biotechnology Biotechnology is the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services. The term ''biotechnology'' was first used ...
*
Ecocide Ecocide is human impact on the environment causing mass destruction to that environment. Ten nations have codified ecocide as a crime. Activities that might constitute ecocide in these nations include substantially damaging or destroying ecos ...
*
Ecophagy Ecophagy is a term coined by Robert Freitas that means the literal consumption of an ecosystem. It derives from the Greek "οἶκος" (), which refers to a "house" or "household", and the Greek "φαγεῖν" (), "to eat". Freitas used the te ...
*
Santa Claus machine A Santa Claus machine, named after the folkloric Santa Claus, is a hypothetical machine that is capable of creating any required object or structure out of any given material. It is most often referenced by futurists and science fiction writers wh ...
*
3D printing 3D printing or additive manufacturing is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer co ...
*
Nanotechnology in fiction The use of nanotechnology in fiction has attracted scholarly attention. The first use of the distinguishing concepts of nanotechnology was "There's Plenty of Room at the Bottom", a talk given by physicist Richard Feynman in 1959. K. Eric Drexle ...


References


External links


Molecular Dynamics Studio (2016)
free open-source multi-scale modeling and simulation program for nano-composites with special support for structural DNA nanotechnology (originally Nanoengineer-1 by Nanorex)
Nano-Hive: Nanospace Simulator (2006)
free software for modeling nanotech entities

of molecular manufacturing technologies
Center for Responsible Nanotechnology (2008)Molecular Assembler website (2008)Rage Against the (Green) Machine (2003)
in
Wired ''Wired'' (stylized as ''WIRED'') is a monthly American magazine, published in print and online editions, that focuses on how emerging technologies affect culture, the economy, and politics. Owned by Condé Nast, it is headquartered in San ...

Government launches nano study
UK EducationGuardian, 11 June 2003
Unraveling the Big Debate over Small Machines (2004)
from BetterHumans.com

by Ralph Merkle

— online technical book: first comprehensive survey of molecular assemblers (2004) by Robert Freitas and Ralph Merkle

(2003)

(2006)
Nanofactory technologyIntegrated Nanosystems for Atomically Precise Manufacturing
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United States ...
Workshop – August 5–6, 2015 {{DEFAULTSORT:Molecular Assembler Nanotechnology Molecular machines Self-replication