Nanotechnology

Animated representation of a carbon nanotube.

Nanotechnology is the manipulation of matter on a nanometric scale. The earliest description of nanotechnology refers to the particular technological goal of precisely manipulating atoms and molecules for the manufacture of microscale products, now also referred to as molecular nanotechnology. Subsequently a more general description of nanotechnology was established by the National Nanotechnology Initiative, which defines nanotechnology as the manipulation of matter with at least one dimension of size between 1 and 100 nanometers. This definition reflects the fact that quantum mechanical effects are important at this scale of the quantum domain, and thus the definition changed from a particular technological goal to a category of research including all types of research and technologies involved. with the special properties of matter that occur below a certain size threshold. It is common to use the plural form of "nanotechnologies" as well as "nanoscale technologies" to refer to the wide range of research and applications whose common theme is their size. Due to the variety of potential applications (including industrial and military applications), governments have invested billions of dollars in nanotechnology research. Through its National Nanotechnology Initiative, the United States has invested $3.7 billion. The European Union has invested^{[citation needed]} 1.2 billion and Japan 750 million dollars.

Size-defined nanotechnology is naturally a very broad field, including different disciplines of science as diverse as surface science, organic chemistry, molecular biology, semiconductor physics, microfabrication, etc. Research and Associated applications are equally diverse, ranging from extensions of device physics to entirely new approaches based on molecular self-assembly, from the development of new materials with nanoscale dimensions to the direct control of matter at the atomic scale.

Scientists are currently debating the future implications of nanotechnology. Nanotechnology may be able to create new materials and devices with a vast scope of applications, such as in medicine, electronics, biomaterials, and energy production. On the other hand, nanotechnology raises the same concerns as any new technology, including concerns about the toxicity and environmental impact of nanomaterials, and their potential effects on the global economy, as well as speculation about various doomsday scenarios. These concerns have led to debate among various advocacy groups and governments about whether special regulations are required for nanotechnology.

Difference between nanotechnology and nanoscience

Nanotechnology encompasses the study, design, creation, synthesis, manipulation, and application of materials, devices, and functional systems through the control of matter at the nanoscale, and the exploitation of phenomena and properties of matter at the nanoscale. When matter is manipulated on such a minuscule scale, it exhibits entirely new phenomena and properties. Therefore, scientists use nanotechnology to create novel and inexpensive materials, devices, and systems with unique properties. However, nanoscience is a discipline dedicated to the study of physical, chemical and biological phenomena that occur at the nanometer scale. Currently there are many instruments and devices with nanometric dimensions and precision that facilitate this process.

History

The 1965 Nobel Prize winner in Physics, Richard Feynman, was the first to refer to the possibilities of nanoscience and nanotechnology in a speech he gave at Caltech (California Institute of Technology) on December 29, 1959, entitled There's Plenty of Room at the Bottom (There's Plenty of Room at the Bottom), in which he describes the possibility of synthesis via direct manipulation of atoms. The term "nanotechnology" it was first used by Norio Taniguchi in 1974, although this is not widely known.

Comparisons of the sizes of nanomaterials.

Inspired by Feynman's concepts, K. Eric Drexler independently used the term "nanotechnology" in his 1986 book Engines of Creation: The Coming Era of Nanotechnology, in the who proposed the idea of an "assembler" At the nanoscale it would be able to build a copy of itself and other items of arbitrary complexity with an atomic level of control. Also in 1986, Drexler co-founded The Foresight Institute (in Spanish: El Instituto de Estudios Prospectives), with which he is no longer associated, to help increase public awareness and understanding of the concepts of nanotechnology and its implications.

Thus, the emergence of nanotechnology as a field in the 1980s occurred by the convergence of the theoretical and public work of Drexler, who developed and popularized a conceptual framework for nanotechnology, and the highly visible experimental advances that attracted additional wide-scale attention to the prospects of atomic control of matter.

For example, the invention of the scanning tunneling microscope in 1981 provided unprecedented visualization of individual atoms and bonds, and it was successfully used to manipulate individual atoms in 1989. Microscope developers Gerd Binnig and Heinrich Rohrer of the IBM Zurich Research Laboratory (Spanish: Laboratorio de Investigación Zúrich IBM) received a Nobel Prize in Physics in 1986. Binnig, Quate, and Gerber also invented the analog atomic force microscope that year.

Buckminsterfullereno C₆₀, also known as buckybola, is a representative member of the carbon structures known as fullerenos. The members of the fullerene family are a main subject of research that falls under the interest of nanotechnology.

Fullerenes were discovered in 1985 by Harry Kroto, Richard Smalley, and Robert Curl, who together won the 1996 Nobel Prize in Chemistry. C₆₀ was not initially described as nanotechnology; the term was used in connection with later work on related graphene tubes (called carbon nanotubes and sometimes also bucky tubes) suggesting potential applications for nanoscale electronics and devices.

In the early 2000s, the field garnered increased scientific, political, and commercial interest that led to both controversy and progress. Controversies arose regarding the definitions and potential implications of nanotechnologies, exemplified by the Royal Society report on nanotechnology. Challenges arose from the feasibility of applications envisioned by proponents of molecular nanotechnology, culminating in a public debate between Drexler and Smalley in 2001 and 2003.

Meanwhile, commercialization of products based on advances in nanoscale technologies began to emerge. These products are limited to bulk applications of nanomaterials and do not involve atomic control of matter. Some examples include the Nano Silver platform that uses silver nanoparticles as an antibacterial agent, transparent nanoparticle-based sunscreens, and carbon nanotubes for stain-resistant fabrics.

Governments moved to promote and fund nanotechnology research, beginning with the United States with its National Nanotechnology Initiative, which formalized the definition of nanotechnology based on size and created a research funding fund of the nanoscale.

By the mid-2000s, serious new scientific attention began to flourish. Projects emerged to produce a roadmap for nanotechnology that focused on the precise atomic manipulation of matter and discussed existing and projected capabilities, goals, and applications.

Other people in this area were Rosalind Franklin, James Dewey Watson and Francis Crick who proposed that DNA was the main molecule that played a key role in regulating all the processes of the organism, revealing the importance of molecules as determinants in life processes.

But this knowledge went further, since with this it was possible to modify the structure of the molecules, as is the case of the polymers or plastics that we find in our homes today. But it must be said that these types of molecules can be considered “large”.

Today, medicine is more interested in research in the microscopic world, since it is possible to find the structural alterations that cause diseases, and it goes without saying that the branches of medicine that have benefited the most such as microbiology, immunology, physiology; New sciences such as Genetic Engineering have also emerged, which has generated controversy over the repercussions of processes such as cloning or eugenics.

The development of nanoscience and nanotechnology in Latin America is relatively recent, compared to what has happened globally. Countries such as Mexico, Costa Rica, Argentina, Venezuela, Colombia, Brazil and Chile contribute worldwide with research work in different areas of nanoscience and nanotechnology. In addition, some of these countries also have educational programs at the undergraduate level, master's, postgraduate and specialization in the area.

Fundamental concepts

Nanotechnology is the engineering of functional systems on a molecular scale. This covers both current work and concepts that are more advanced. In its original sense, nanotechnology refers to the projected ability to build elements from the smallest to the largest, using techniques and tools, which are currently being developed, to build complete high-performance products.

A nanometer (nm) is one billionth, or 10⁻⁹, of a meter. For comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the 0.12–0.15 nm and a DNA double helix has a diameter of about 2 nm. The smallest cellular life form, on the other hand, bacteria of the genus Mycoplasma, are around 200 nm long. By convention, nanotechnology is measured in the scale range of 1 to 100 nm according to the definition used by the National Nanotechnology Initiative in the United States. The lower limit is given by the size of the atoms (hydrogen has the smallest atoms, having a radius of about one-twentieth of a nm known as the Bohr radius) since nanotechnology must make its devices out of atoms and molecules.. The upper limit is more or less arbitrary, but lies around the size at which phenomena that cannot be observed in larger structures begin to become apparent and can be used in the nanodevice. These new phenomena make nanotechnology distinct from devices that are merely miniaturized versions of an equivalent macroscopic device; such devices are on a larger scale and fall under the description of microtechnology.

To put the scale in another context, the comparative size of a nanometer to a meter is the same as that of a rock the size of the Earth. Another way of putting it: a nanometer is the amount by which the beard of the average man grows in the time it takes him to raise the razor to his face.

Two approaches to nanotechnology are used. In the 'bottom-up' approach, materials and devices are built from molecular components that chemically assemble themselves by the principles of molecular recognition. In the "top-down" approach, nano-objects are built from larger entities with control at the atomic level.

Areas of physics such as nanoelectronics, nanomechanics, nanophotonics, and nanoionics have evolved over the past few decades to provide a basic scientific foundation for nanotechnology.

From the biggest to the smallest: a perspective from the materials

Image of a reconstruction of a clean Gold surface(100) as can be seen using a tunnel effect microscope. You can see the positions of the individual atoms that make up the surface.

Various phenomena become pronounced as the size of the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the "quantum size effect" where the electronic properties of solids are altered with large reductions in particle size. This effect does not come into play when going from the macro dimensions to the micro dimensions. However, quantum effects can become significant when the nanometer size is reached, usually at distances of 100 nanometers or less, the so-called quantum domain. Additionally, a variety of physical properties (mechanical, electrical, optical, etc.) change when compared to macroscopic systems. An example is the increase in the ratio of surface area to volume by altering the mechanical, thermal and catalytic properties of materials. Diffusion and reactions at the nanoscale level, nanostructure materials and nanodevices with rapid ion transport are generally known as nanoionics. The mechanical properties of nanosystems are of interest in nanomechanics research. The catalytic activity of nanomaterials also opens up potential risks in their interaction with biomaterials.

Materials reduced to the nanoscale can display different properties when compared to those they exhibit at the macroscale, allowing for unique applications. For example, opaque substances can become transparent (copper); stable materials can be turned into fuel (aluminum); insoluble materials can become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a powerful chemical catalyst at nanoscales. Most of the fascination with nanotechnology arises from these quantum and surface phenomena that matter exhibits at the nanoscale.

From the simple to the complex: a molecular perspective

Modern synthetic chemistry has reached the point where it is possible to prepare small molecules for almost any structure. These methods are used today to make a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. This ability raises the question of extending this kind of control to the next larger level, searching for methods to assemble these unique molecules into supramolecular structures or assemblies consisting of many molecules arranged in a well-defined fashion.

These approaches use the concepts of molecular self-assembly and/or supramolecular chemistry to automatically arrange their own structures into some useful ordering through a bottom-up approach. The concept of molecular recognition is especially important: molecules can be designed in such a way that a specific configuration or arrangement is favored due to non-covalent intermolecular forces. The Watson-Crick base pairing rules are a direct result of this, as is the specificity of an enzyme being targeted to a single substrate or the folding of the protein itself. Thus, two or more components can be designed for complementarity and mutual attraction in such a way that they build a more complex and useful whole.

Bottom-up approaches should be capable of producing devices in parallel and be much cheaper than top-down methods, but could potentially be outgrown as the size and complexity of the desired assembly increases. The most successful structures require complex and thermodynamically unlikely arrangements of atoms. However, there are many examples of self-assembly based on molecular recognition in biology, one of the most notable being Watson-Crick base pairing and enzyme-substrate interactions. The challenge for nanotechnology is to discover if these principles can be used to achieve new constructions in addition to the existing natural ones.

Molecular nanotechnology: a long-term view

Molecular nanotechnology, sometimes called molecular manufacturing, describes manufactured nanosystems (nanoscale machines) operating at the molecular scale. Molecular nanotechnology is especially associated with the molecular assembler, a machine that can produce a desired structure or device atom by atom using the principles of mechanosynthesis. Fabrication in the context of productive nanosystems is not related to, and should be clearly distinguished from, conventional technologies used for fabrication of nanomaterials such as nanotubes and carbon nanoparticles.

When the term "nanotechnology" was independently coined and popularized by Eric Drexler (who at the time was unaware of an earlier use by Norio Taniguchi) to refer to a future manufacturing technology based on molecular machine systems. The premise was that molecular-scale biological analogies of traditional machine components demonstrated that molecular machines were possible: there are countless examples in biology, it is known that sophisticated stochastically optimized biological machines can be produced.

It is hoped that developments in nanotechnology will make it possible to build them by some other means, perhaps using principles of biomimicry. However, Drexler and other researchers have proposed that an advanced nanotechnology, though perhaps initially implemented by biomimetic means, could ultimately be based on mechanical engineering principles, that is, a manufacturing technology based on the mechanical functionality of these components. (such as gears, bearings, motors, and structural members) that would allow programmable and positional assembly to atomic specification. The physics and engineering performance of example designs were discussed in Drexler's book Nanosystems.

In general it is very difficult to assemble devices on an atomic scale, since one has to position atoms on top of other atoms of comparable thickness and size. Another view, expressed by Carlo Montemagno, is that future nanosystems will be hybrids of silica technology and biological molecular machines. Richard Smalley argues that mechanosynthesis is impossible due to difficulties in the mechanical manipulation of individual molecules.

This led to an exchange of letters between Chemical & ACS Engineering News in 2003. Although biology clearly demonstrates that molecular machine systems are possible, nonbiological molecular machines are currently only in their infancy. Leaders in nonbiological molecular machine research are Alex Zettl and his colleagues at Lawrence Berkeley National Laboratory and UC Berkeley. They have built at least three distinct molecular devices whose movements are controlled from the desktop by changing the voltage: a nanotube nanomotor, an actuator, and a nanoelectromechanical relaxation oscillator. See carbon nanotube nanomotor for more examples.

An experiment indicating that positional molecular assembly is possible was performed by Ho and Lee at Cornell University in 1999. They used a scanning scanning microscope to move a carbon monoxide (CO) molecule toward an atom individual iron (Fe) located in a flat silver crystal, and chemically bond the CO with the Fe by applying a voltage.

Current Research

Graphic representation of a rotaxan, useful as a molecular switch.

This DNA tetrahedron is an artificially designed nanostructure of the type built in the field of DNA nanotechnology. Each tetrahedron edge is a double DNA-based propeller, and each vertex is a three-armed union.

This device transfers energy from layers of nano thickness from quantum wells to nanocrystals located above, causing the nanocrystals to emit visible light.

Nanomaterials

The field of nanomaterials includes subfields that develop or study materials that have unique properties arising from their nanoscale dimensions.

• Interface and colloid science has identified many materials that can be useful in nanotechnology, such as carbon nanotubes and other fullerene, and several nanoparticles and nanoroids. The nanomaterials with rapid transport of ions are also related to nanoyonics and nanoelectronics.
• Nanoscale materials can also be used for volume applications; most of the current commercial applications of nanotechnology are of this type.
• Progress has been made in the use of these materials for medical applications, see nanomedicine.
• Materials to nanoscales such as nanopillars are sometimes used in solar cells to lower the costs of traditional silicon solar cells.
• The development of applications that incorporate semiconductor nanoparticles that will be used in the next generation of products, such as screen technology, lighting, solar cells and biological images; see quantum point.

Bottom-up approach

These seek to arrange smaller components into more complex structures.

• DNA nanotechnology uses the specificity of Watson-Crick's base pair to build well-defined structures from DNA and other nucleic acids.
• It is approaching from the field of "classical" chemical synthesis (inorganic and organic synthesis) and also its objective is the design of molecules with a well-defined form (e.g. bis-peptides).
• More generally, molecular self-assembly seeks to use the concepts of supramolecular chemistry and molecular recognition in particular, to cause uni-molecular components to be automatically disposed of by themselves in some useful conformation.

Top-down approach

They seek to create smaller devices using larger ones to control their assembly.

• Many technologies that trace their origin to solid silicon state methods to manufacture microprocessors are now able to create smaller features than 100 nm, it falls into the definition of nanotechnology. Hard disks based on the giant magnetor resistance already on the market fall within this description, as well as the techniques of deposition of atomic layers (in English: Atomic Layer Deposition, ALD). Peter Grünberg and Albert Fert received a Nobel Prize in Physics in 2007 for their discovery of giant magnetor resistance and their contributions to the field of spintronics.
• Solid state techniques can also be used to create devices known as nanoelectromechanical systems (in English: Nanoelectromechanical Systems, NEMS), which are related to microelectromechanical systems (in English: Microelectromechanical Systems, MEMS).
• You make ionic concentrates can be controlled to remove or deposit material when appropriate precursor gases are applied at the same time. For example, this technique is routinely used to create sub-100 nm material sections for analysis using electronic transmission microscopes.
• The tips of atomic force microscopes can be used as a "written head" to nanoscale to deposit a chemical on a surface in a desired pattern in a process known as dip-pen nanolitography, which is then followed by a waterproof process to remove the material in a top-down method. This technique falls into the largest subfield of nanolitography.

Functional approaches

They seek to develop components of a desired functionality regardless of how they might be assembled.

• The molecular scale electronics seeks to develop molecules with useful electronic properties. These could then be used as single molecule components on a nanoelectronic device. For an example see the rotaxano.
• Synthetic chemical methods can also be used to create synthetic molecular engines, such as nanoauto.

Biomimetic approaches

• Bionics or biomymesis seek to apply the biological methods and systems found in nature, to study and design modern engineering and technology systems. Biomineralization is an example of the systems studied.
• Bionanotechnology is the use of biomolecules for applications in nanotechnology, including the use of viruses and lipid assemblies. The nanocellulose is a potential application on a massive scale.

Speculative

These subfields seek to anticipate what nanotechnological inventions might achieve or attempt to propose an agenda that mandates a path by which research can progress. Often these take a large-scale view of nanotechnology, with more emphasis on its social implications than on the details of how such inventions could actually be created.

• Molecular nanotechnology is proposed as an approach involving the manipulation of a single molecule in a finely controlled and deterministic way. This is more theoretical than other subfields, and many of the proposed techniques are beyond the current capabilities.
• The nanorobotic focuses on self-sufficient machines with some functionality operating on nanoscale. There are hopes of being able to apply nanorobots in medicine, although previously the disadvantages of such devices should be overcome. However, progress has been shown in innovative materials and methodologies with some patents granted for new nano-manufacturing devices for future commercial applications, which also progressively assist in the development of nanorobots with some use of embedded nanobioelectronic concepts.
• The productive nanosystems are "nunsystems" that will be nanosystems that produce atomically accurate parts for other nanosystems, not necessarily using new emerging nanocurrant properties, but the well understood foundations of macroscopic manufacturing. Due to the discreet (at the atomic level) nature of matter and the possibility of exponential growth, this stage is seen as the basis of another industrial revolution. Mihail Roco, one of the architects of the National Nanotechnological Initiative of the United States, has proposed four nanotechnology states that seem to be a parallel to the technical progress of the Industrial Revolution, progressing from passive nanostructures to active nanodevices to complex nanomachines and finally to productive nanosystems.
• The programmable matter seeks to design materials whose properties can be easily, reversibly and externally controlled. It is designed as a fusion between the science of information and the science of materials.
• Because of the popularity and media exposure of the term nanotechnology, the words picotechnology and femtotechnology have been coined similarly, although these are rarely used and only informally.

Tools and Techniques

Typical configuration of an atomic force microscope. A microfabricated voladizo with an acute tip is diverted by the characteristics of a sample surface, similar to a phonograph, but to a much smaller scale. A laser beam is reflected in the back of the voladizo in a set of photodetctors, allowing the detour to be measured and to be put into a surface image.

There are several important modern developments. The atomic force microscope (AFM) and scanning tunneling microscope (STM) are early versions of the scanning probes that launched nanotechnology. There are other types of scanning probe microscope. Although conceptually similar to scanning confocal microscopes developed by Marvin Minsky in 1961 and the Scanning Acoustic Microscope (SAM) developed by Calvin Quate and associates in the 1970s, confocal scanning microscopes Newer scans have a much higher resolution, since they are not limited by the wavelength of sound or light.

The tip of a scanning probe can also be used to manipulate nanostructures (a process known as positional assembly). The feature-oriented scanning methodology suggested by Rostislav Lapshin appears to be a promising way to implement these nanomanipulations in automatic mode. However, this is still a slow process due to the low scanning speed of the microscope.

Various nanolithography techniques such as optical lithography, X-ray lithography dip-pen nanolithography, electron beam lithography or nanoimprint lithography were also developed. Lithography is a top-down manufacturing technique where raw material is reduced in size to a nanoscale pattern.

Another group of nanotechnological techniques include those used for the manufacture of nanotubes and nanowires, those used in the manufacture of semiconductors such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, lithography nanoimprinting, atomic layer deposition and molecular vapor deposition, and also including molecular self-assembly techniques such as those employing di-block copolymers. The precursors of these techniques predate the nanotechnology era, and are extensions of developing scientific advances rather than techniques that were devised solely for the purpose of creating nanotechnology and were the result of nanotechnology research.

The top-down approach anticipates nanodevices that must be built piece by piece in stages, the same way other things are manufactured. Scanning probe microscopy is an important technique for both the characterization and synthesis of nanomaterials. Atomic force microscopes and scanning tunneling microscopes can be used to examine surfaces and to move atoms on them. By designing different tips for these microscopes, they can be used to carve out structures on surfaces and to help guide self-assembled structures. Using, for example, the feature-oriented scanning approach, atoms or molecules can be moved on the surface with scanning probe microscope techniques. Currently, it is expensive and time consuming to use in production on mass, but they are very suitable for experimentation in a laboratory.

In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, self-assembly, and positional assembly. Dual polarization interferometry is a suitable tool for the characterization of self-assembled thin films. Another variation of the bottom-up approach is Molecular Beam Epitaxy (MBE) growth. Bell Telephone Laboratories researchers such as John R. Arthur, Alfred Y. Cho, and Art C. Gossard developed and implemented the MBE as a research tool in the late 1960s and 1970s. Samples made by the MBE were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. MBE allows scientists to arrange atomically precise layers, and in the process, build complex structures. Important for semiconductor research, EBM is also widely used to make samples and devices for the newly emerging field of spintronics.

However, new therapeutics, based on sensitive nanomaterials, such as Transfersome stress-sensitive ultradeformable vesicles, are under development and are approved for human use in some countries.

Technological development to access nanotechnology.

One of the key instruments in micro and nano science are scanning probe microscopes. They basically consist of a platform and a probe that sweeps or scans the sample.

Scanning can be done by moving either the probe or the platform, using high-precision actuators. Actuators are a key factor of this technology.

The probe can be raised or lowered, thus having a system with three coordinate axes, on the one hand an x-y scanning plane and on the other hand a height z, with which the relief or topography of the surface can be studied. the microstructures.

Not only is the geometry of the sample measured, but depending on the type of probe used, chemical, thermal, electrical or mechanical properties can also be measured, thus opening a very wide window of information, which allows studying the properties of nanomaterials.

Investment

Some developing countries already allocate significant resources to nanotechnology research. Nanomedicine is one of the areas that can contribute the most to the sustainable advancement of the Third World, providing new methods for diagnosis and screening of diseases, better drug delivery systems and tools for monitoring some biological parameters.

About forty labs around the world funnel vast amounts of money into nanotechnology research. Some three hundred companies have the term “nano” in their name, although there are still very few products on the market.^{[citation needed]}

Some computer giants such as IBM, Hewlett-Packard (HP), NEC and Intel are investing millions of dollars a year in the field. The governments of the so-called First World have also taken the issue very seriously, with the clear leadership of the US government, which dedicates hundreds of millions of dollars to its National Nanotechnology Initiative.

In Spain, scientists talk about “nanobudgets”. But interest is growing, since there have been some conferences on the subject: in Seville, at the San Telmo Foundation, on investment opportunities, and in Madrid, with a meeting between heads of nanotechnology centers from France, Germany and the United Kingdom in the Autonomous University of Madrid.

Traditional industries will be able to benefit from nanotechnology to improve their competitiveness in common sectors, such as textiles, food, footwear, automotive, construction and health. What is intended is that companies belonging to traditional sectors incorporate and apply nanotechnology in their processes in order to contribute to the sustainability of employment. Currently the figure in daily use is 0.2%.

Interdisciplinary assembly

The fundamental characteristic of nanotechnology is that it constitutes an interdisciplinary assemblage of various fields of the natural sciences that are highly specialized. Therefore, physicists play an important role not only in the construction of the microscope used to investigate such phenomena, but also in all the laws of quantum mechanics. Reaching the structure of the desired material and the configurations of certain atoms make chemistry play an important role. In medicine, the specific development aimed at nanoparticles promises help in the treatment of certain diseases. Here, science has reached a point where the boundaries that separate the different disciplines have begun to blur, and it is precisely for this reason that nanotechnology is also referred to as a convergent technology.

A possible list of sciences involved would be the following:

• Chemistry (Moleculars and Computations)
• Biochemistry
• Molecular biology
• Physics
• Electronics
• Computer
• Maths
• Medicine
• Nanoingenieria

Advanced nanotechnology

Advanced nanotechnology, sometimes also called molecular manufacturing, is a term given to the concept of engineering nanosystems (machines on the nanoscale) operating on the molecular scale. It is based on the fact that manufactured products are made from atoms. The properties of these products depend on how those atoms are arranged. Thus, for example, if we relocate the atoms of the graphite (composed of carbon, mainly) from the pencil lead, we can make diamonds (pure crystallized carbon). If we relocate the atoms of the sand (basically composed of silica) and add some extra elements, the chips of a computer are made.

From the countless examples found in biology it is known that billions of years of evolved feedback can produce sophisticated and stochastically optimized biological machines. It is hoped that developments in nanotechnology will make their construction possible through some shorter meanings, perhaps using biomimetic principles. However, K. Eric Drexler and other researchers have proposed that advanced nanotechnology, although perhaps initially implemented through mimetic principles, could ultimately be based on mechanical engineering principles.

Determining a set of paths forward for the development of molecular nanotechnology is a goal for the technology roadmap project led by the Battelle Memorial Institute (the head of several US national laboratories) and Foresight Institute. That map should be completed by the end of 2006.

Future applications

According to a report by a group of researchers from the University of Toronto, Canada, the fifteen most promising applications of nanotechnology are:

• GM foods.
• Storage, production and conversion of energy.
• Arms and defense systems.
• Molecular thermal changes (Nanothermal).
• Construction.
• Malnutrition control in poor places.
• Cosmetic.
• Diagnosis and disease description.
• Detection and control of pests.
• Computer.
• Health monitoring.
• Food processing.
• Agricultural production.
• Resolution of air pollution.
• Drug management systems.
• Water treatment and remediation.
• Renewable energies: Currently, the demand is mainly covered by non-renewable power plants (fossil fuels, radioactive materials). However, the increase in employment in renewable energies is increasing by making current infrastructures insufficient and expensive, making the introduction of nanotechnology in this area necessary. It is believed that in the future this could change the existing energy matrices. One of the solutions is the replacement of Aquiles heel batteries, whose storage capacity is insufficient, by flow batteries. This type of batteries would be based on the use of liquids containing a network of nanoscale fluctuating particles and could become much cheaper.

Current applications with nanotechnology

Textile. Development of smart fabrics: capable of repelling stains, being self-cleaning, anti-odor or having nanochips to change color and temperature.

Agriculture. Design of products to improve pesticides, herbicides and fertilizers. The main purpose is soil improvement. In addition, we can include in this category nano sensors for the detection of water, nitrogen, agrochemicals, etc.

Cosmetics. Development of anti-wrinkle creams or sun creams with nanoparticles.

Livestock. Development of nanoparticles for the purpose of administering vaccines or drugs to animals, as well as for detecting microorganisms, diseases and toxic substances.

Food. Devices (nanosensors and nanochips) that function mainly as an electronic nose and tongue, that is, to analyze aspects related to smell and taste. They are also used to detect the freshness and shelf life of a food, pathogens, additives, drugs, heavy metals, toxins, contaminants... On the other hand, another highly developed aspect is the creation of nanopackaging, as will be explained in the next section. These have functional, nutritious, healthy and organoelectric properties (descriptions of the physical characteristics that matter has according to what can be perceived by the senses, such as taste, texture, smell, color or temperature).

Nanotechnology applied to food packaging

Food preservation is an idea that dates back to the beginning of human history. Since prehistoric times, the need to improve food preservation through different techniques has been a characteristic of human behavior. Fermentation, salinization, sun drying, roasting, curing, irradiation, carbonation, and the addition of chemical and physical preservatives have been developed since the beginning of humanity. All these methods have the same central idea. Archaeological evidence supports the idea that preservation techniques were developed in the Greek, Roman, and Egyptian civilizations. However, the various methods present the challenge of maintaining the original conditions for long periods of time.

Food packaging methods aim to ensure the quality of food so that it remains intact with its properties. The main packaging aims to provide physical protection in order to prevent contamination of food with other foods or with microorganisms. The packaging materials are preferably made of biodegradable materials, with the purpose of reducing environmental contamination. This idea has been carried out thanks to the introduction of nanotechnology.

One of the applications of nanotechnology in the field of food packaging is the application of materials added with nanoclays, which improve mechanical, thermal, and gas barrier properties, among others; of packaging materials. In the case of improving the gas barrier, the nanoclays create a tortuous path for the diffusion of the gaseous molecules, which makes it possible to achieve a similar barrier with lower thicknesses, thus reducing the costs associated with the materials.

The processes for incorporating nanoparticles can be carried out by extrusion or by coating, and the parameters to be controlled in the materials additivation process are: nanoparticle dispersion, nanoparticles interaction with the matrix, aggregations that may occur between the nanoparticles and the amount of nanoparticles incorporated.

Nanosensors help detect any change in the color of food and help detect gases within the product. These sensors are usually sensitive to gases such as hydrogen, hydrogen sulfide, nitrogen oxides, sulfur dioxide, and ammonium. Nanosensors are data-processing devices capable of detecting changes in the level of light, heat, humidity, gases, and electrical and chemical signals.

Nanoemulsions are used to produce foods for salad dressing, flavoring oils, sweeteners and others- They help in the release of different flavors with the stimulation that is related to heat, pH, ultrasound waves, etc. Nanoemulsions can efficiently retain flavors and prevent oxidation and enzymatic reactions. Nanoemulsions are created primarily through high-energy engagement with high-pressure homogenization, ultrasonic methods, high-speed liquid coaxial jets, and high-speed device methods. Similarly, low energy methods involve membrane emulsification, spontaneous emulsification, solvent displacement, emulsion inversion point, and through phase inversion points. Nanoemulsions are created by dispersing the liquid phase in a continuous aqueous phase. The components that are used for the creation of nanoemulsions are of the lipophilic type.

Nanotechnology applied to drug delivery

Within the possibilities of drug administration, the possibility of using nanotechnology as a system for the release of the active principle has arisen. In general, the vehicles used to administer a drug must be of low toxicity, with optimal properties for transport and release, and a long half-life. Examples of nanosystems are: micelles, liposomes, dentrimers, nanoparticles, nanotubes, and bioconjugates.

Nanoparticles are colloidal solid particles with a size of 1 nm to 1000 nm that are used as drug delivery agents. With this, an increase in the dissolution rate and the saturation limit of solubility is achieved. There is also a special type called solid lipid nanoparticles (SLN). These nanoparticles protect the active principle against chemical degradation, in addition to generating greater flexibility in the modulation of drug release.

Liposomes are amphiphilic molecules, such as phospholipids, that form vesicles of bilayered membranes that can lead to vesicles. Liposomes are spherical structures formed by one or more layers that contain an aqueous phase inside. Liposomes have been used to enhance the therapeutic effect of very potent drugs. This delivery system is considered to reduce toxicity.

The bioconjugates or polymeric conjugates act as carriers and as biological components (peptides, proteins, nucleotides) that act as ligands for specific or targeted therapeutic effects. An example of bioconjugates with the products obtained from the addition of polyethylene glycol (PEG) to drugs or therapeutic proteins.

The dendrons or dendrimers are nanomaterials that can incorporate synthetic polymer blocks or natural components. Its hierarchical factorial structure presents numerous conjugation sites for charges or target motifs.

Inorganic nanoparticles are nanoparticles built from inorganic materials. The most common materials are quantum dots along with gold, silver, iron oxide, or mesoporous nanoparticles. Characteristic properties of each material are size, charge, surface chemistry, and structure.

One of the first drugs in nanomedicine that was shown to be safe by the FDA was obtained by encapsulating doxorubicin within liposomes. This nanoformulation improved the pharmacokinetic and distribution characteristics of doxorubicin, leading to prolongation of half-life and generating an accumulation process in tumor tissue.

In recent years, implantable drug delivery devices have been developed. The main function of this new technology is controlled drug delivery over several weeks to months, according to the therapeutic needs of an individual patient. Long-term therapies can help improve patient compliance and adherence to drug treatments. Implantable devices use an on demand strategy of therapeutic agents and some technologies would help to control the release remotely, using radiofrequency, ultrasound energy and magnetic fields, the administrations could be activated and controlled. Despite the large number of reported studies on self-regulating medical devices and technological efforts, the benefits of this type of technology have not been proven.

Nanotechnology applied to cancer therapy

One of the most challenging aspects of existing cancer therapies is the specificity of the treatments. This could lead to reducing the toxic effects that are generated after administering anticancer therapies. In addition to this possibility, the solubility and bioavailability of drugs that are poorly soluble could be improved. Due to these needs, some investigations have emerged that use nanocarriers (liposomes, polymeric micelles, and polymeric nanoparticles) for the preparation of new formulations that improve the bioavailability of these treatments and improve the distribution of the anticancer drug at the tumor site. Among the factors that are considered to be of the physicochemical type, there is the Z potential, the particle size, the cationic charge of the surface and the solubility.

Nanotechnology applied to HIV/AIDS therapy

Drug delivery approaches applied to systemic delivery of antiviral drugs could have similar advantages to successful examples in cancer therapy. Controlled release systems could increase the half-life of drugs, maintaining plasmatic concentrations at therapeutic levels for longer periods of time that ultimately have an impact on the efficacy of drug therapy. Additionally, a better safety profile could be obtained that leads to better patient adherence. Specifically, the targeted distribution of antiviral drugs against CD4+ cells and macrophages, as well as the distribution to organs with difficult access such as the brain, which could ensure the maintenance of concentrations through the generation of latent reserves. Together with the improvement of pharmacological therapy, the idea of achieving gene therapy through nanotechnology was born. Gene therapy appears to be promising, in which a gene is inserted into a cell to lead to interference with the infection or replication processes. There is evidence indicating that gene silencing could be a potential tool to target genes of interest. It has also been described that it could be possible to generate vaccines that are effective and safe against HIV/AIDS. It is possible to use encapsulated antigens in their center from which antigen presenting cells can process, present and cross-present antigens to CD4+ and CD8+ cells, respectively, or absorb antigens on their surface, allowing B cells to mount a humoral response.. On the other hand, immunotherapy for HIV/AIDS based on viral agents and administration of autologous dendritic cells generated ex-vivo.

Nanotechnology applied to Alzheimer's therapy

Nanotechnology treatment methods have produced interesting results in the therapy of Alzheimer's disease. Drugs usually available for the treatment of Alzheimer's disease include drugs that are inhibitors of the enzyme acetylcholinesterase, which have poor solubility and low bioavailability. Additionally, these drugs have an inability to cross the blood-brain barrier, so improving the distribution of these drugs at the site of action is technologically challenging. The nanotechnologies included are polymeric nanoparticles, solid-lipid nanoparticles, lipid nanostructure carriers, microemulsion, nanoemulsion, and liquid crystals. The special physicochemical characteristics of the drugs available for the treatment of Alzheimer's lead to therapeutic failure in many cases. These limitations have been overcome, in part, due to the development of intranasal administration, which favors a non-invasive alternative for drug distribution at the central nervous system level, through passage through the blood-brain barrier.

DNA nanotechnology

Applications of nanotechnology in cell biology have a challenging focus on the deoxyribonucleic acid (DNA) molecule. Structural elements with a certain molecular logic have been developed to carry out therapeutic actions in a certain cell type or tissue, leading to greater specificity and reducing the undesirable effects of conventional therapies. In addition, DNA nanostructures can be used as a programmable binding of drugs, target ligands and other modifications or systems such as lipid bilayers. On the other hand, imaging probes with good sensitivity and specificity have been developed, which are considered DNA-based amplification mechanisms and which can be programmed to specifically interact with ribonucleic acid (RNA) sequences at the intracellular level. Another application is the generation of DNA structures that give precise control to the intracellular spatial organization, providing a basis for developing quantification systems at the subcellular level. DNA nanostructures as drug delivery vehicles have been developed in an important way in the last years. For this purpose, CpG oligodeoxynucleotides (ODNs) can trigger an innate immune response by activating Toll-like receptors of the TLR9 type. Such ODNs have become an interesting therapeutic target because they can be directly integrated into the DNA nanostructure through hybridization. Y-shaped DNA molecules with CpG motifs have been developed that can trigger an immune response by increasing the efficiency of macrophage uptake. Other findings have led to the creation of synthetic vaccine complexes by assembling tetrahedral DNA nanostructures (TDNs) that were modified with streptavidin and CpG ODNs. In that case streptavidin serves as a model antigen leading to the construct generating anti-streptavidin IgG antibodies.

Nanotechnology by country

Argentina

Concept development

According to the Argentine Nanotechnology Foundation (FAN), "The properties of matter change when going from a macroscopic scale to a nanoscopic one... At the nanoscale the intensive properties (color, melting point, density, electrical conductivity and thermal, etc) change surprisingly, they do not depend on the amount of matter. For example, silver, which in different scales acquires different colors."

On the other hand, nanosciences according to the School of Nanosciences and Nanotechnologies of Argentina, unlike nanotechnologies, address the study and explanation of the fundamental and technological aspects of the physical, chemical and/or biological properties and processes that they emerge in systems and materials at the nanoscale; In addition to the different techniques, calculations and tools for the manufacture and control of nanosystems.

History of Nanotechnology in Argentina.

Since the early 2000s, this technology has experienced strong growth throughout the world, from the manufacture of a large number of products benefiting from its contributions. In this context, our country has developed an ecosystem of research groups, companies and other public and private actors that have worked and are working in the same direction.

In March 2004, the first national workshop on nanosciences and nanotechnologies was held at the then Secretariat of Science, Technology and Productive Innovation (SECyT), and currently the Ministry of Science, Technology and Innovation.

It is in 2005 that the State announced the creation of the Argentine Nanotechnology Foundation (FAN) which is still active today and is a very important pillar in the development and production of Nanotechnology in Argentina.

Considered a general-purpose technology due to its ability to offer innovations to very different industries such as medicine, food and electronics, nanotechnology has become a relevant field in the scientific and technological development of countries and Argentina is no exception. Currently, the country has 335 groups in 91 science and technology institutes that develop lines of research on the subject and, in turn, according to the survey carried out, there are 73 national companies that market products or processes with their contributions or are in the process of doing it.

The range of options is really wide. In Argentina, for example, there are companies that manufacture dental implants with bionanomaterials, chinstraps with silver and copper nanoparticles, healthy foods enriched with biodegradable organic nanomaterials or sustainable inputs for agricultural production. To those actors that constitute part of the ecosystem, others are added to empower them; Among them are the technological linkage units, incubators, universities and public organizations that also play a key role in its development.

Geographically, the distribution of institutions that participate in the development of nanotechnology in Argentina is concentrated in the central provinces and specifically in large cities such as the Federal Capital, Córdoba, Río Cuarto, Santa Fe, Rosario, Mendoza, La Plata, Mar del Plata and Bahía Blanca. Although these are the main places, there are also institutes with their research groups and in some cases companies in the northern and southern provinces of the country, mainly in Bariloche and San Miguel de Tucumán, among other cities.

Tools, applications and developments of nanotechnology in Argentina.

Conventional optical microscopes, like the ones we can find in the laboratories of primary and secondary education institutions, are becoming obsolete. Currently, there are very useful tools, high-resolution microscopes, such as the scanning electron microscope (SEM) of the University of Buenos Aires (UBA), which allows us to visualize nanometric systems, such as Cu20 (dioxide copper) used in the agricultural sector as a fungicide.

Argentina currently has an increase in nanotechnology instruments and applications, where 60% of R&D is carried out by research groups in institutes and centers that are located in science and technology organizations or in mostly public universities and some private.

Already in 2011, the Electron Microscopy and X-Ray Analysis Laboratory (LAMARX) acquired a microprobe worth 1.8 million dollars, which is located in the Faculty of Mathematics, Astronomy, Physics and Computing (FAMAF), belonging to the National University of Córdoba (UNC).

Currently, there is also, among others, the Nanofab, a laboratory for advice, incubation and public equipment services that has the participation of more than 25 institutions.

The applications of nanotechnology and nanomaterials cover all types of industrial sectors. In Argentina some of these are:

Environment: According to the FAN "Nanotek S.A. proposes the use of zero-valent iron nanoparticles in groundwater for the absorption of arsenic, a substance that affects a large part of the national territory (16 provinces, 435,000 km2 and 2.5 million inhabitants) and implies a disbursement of 14 million dollars for the budget of the public health area”.

Biomedicine: The pandemic generated by Covid-19 (SARS-CoV-2) led to the creation and improvements of chinstraps, again using technologies developed by Nanotek S.A. which indicate that these chinstraps: "Have silver nanoparticles that release positive ions, capable of altering the biological processes of microorganisms."

Energy: There are 22 groups in Argentina in the direction of producing new materials with greater efficiency for use in the energy sector, for example in the components of windmills (improving their resistance and reducing their weight) and solar panels (semiconductors capable of capturing more solar energy).