| Part of a series of articles on |
| Nanotechnology |
|---|
| Impact and applications |
| Nanomaterials |
| Molecular self-assembly |
| Nanoelectronics |
| Nanometrology |
| Molecular nanotechnology |
Nanoreactors are a form of chemical reactor that are particularly in the disciplines of nanotechnology and nanobiotechnology. These special reactors are crucial in maintaining a working nanofoundry; which is essentially a foundry that manufactures products on a nanotechnological scale.
The term nanoreactor refers to an isolated system on the nanometer scale that is used to run chemical reactions in an environment that differs drastically from a reaction in bulk solution. The synthesis and analysis of these nanoreactors is a highly interdisciplinary subject, spanning from chemistry and physics to biology and materials science. These systems can be synthetic, such as nanopores and hollow nanoparticles, or they can be biological systems, including protein pores and channels. [1] Generally, the effect of confinement provided by these nanoreactors results in novel chemistry. This field has only begun to receive significant attention in the last two decades, and more work is constantly being published as nanoreactors become more sophisticated and begin to show promise for industrial applications.
Researchers in the Netherlands have succeeded in building nanoreactors that can perform one-pot multistep reactions - the next step towards artificial cell-like devices in addition for applications involving the screening and diagnosis of a disease or illness. [2] A biochemical nanoreactor is created simply by unwrapping a biological virus through scientific methods, eliminating its harmful contents, and re-assembling its protein coat around a single molecule of enzyme. [3] The kinetic isotope effect is trapped in a single molecule within a membrane-based nanoreactor. [4] This is a phenomenon that has been found by researchers in the United Kingdom during experiments done in September 2010. [4] The kinetic isotope effect, where the rate of a reaction is influenced by the presence of an isotopic atom in solution, is an important principle for elucidating reaction mechanisms. [4] This recent finding could open up new methods to study chemical reactions. [4] They may even aid in the process of creating new (and even more powerful) nanoreactors. [4]
Using nanocrystals, a scalable and inexpensive process can ultimately create nanoreactors. [5] Researchers at the Lawrence Berkeley National Laboratory in Berkeley have the ability to take advantage of the large difference in select components to create these nanocrystals and nanoreactors. [5] Nanocrystals are easier to use and less expensive than methods that employ sacrificial templates in the creation process of hollow particles. [5] Catalyst particles are separated into shells in order to prevent particle aggregation. [5] Selective entry into the catalysis chamber reduces the likelihood of desired products undergoing secondary reactions. [5]
Nanoreactors can also be built by controlling the positioning of two different enzymes in the central water reservoir or the plastic membrane of synthetic nanoscopic bubbles. [6] Once the third enzyme is added into the surrounding solution, it becomes possible for three different enzymatic reactions to occur at once without interfering with each other (resulting in a "one-pot" reaction). [6] The potential for nanoreactors can be demonstrated by binding the enzyme horseradish peroxidase into the membrane itself; trapping the enzyme glucose oxidase. [6] The surrounding solution would end up containing the enzyme lipase B with the glucose molecules containing four acetyl groups as the substrate. [6] The resulting glucose would cross the membrane, become oxidized, and the horseradish peroxidase would convert the sample substrate ABTS (2,2’-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)) into its radical cation. [6]
Nanoreactors can also be used to emulsify water, create hydrofuels (which essentially blends 15% water into the refined diesel product), play a helpful role in the chemical industry by allowing multiple streams of raw materials to exists in a single nanoreactor, manufacture personal care products (i.e., lotions, pharmaceutical creams, shampoos, conditioners, shower gels, deodorants), and improve the food and beverage industries (by processing sauces, purées, cooking bases for soup, emulsifying non-alcoholic beverages, and salad dressings). [7]
Personal care goods can be enhanced by companies feeding multiple phases of material, using a mixing device with water, and creating instant emulsions. [7] These emulsions would come with smaller particles, are expected to have a longer shelf life and an give off an enhanced appearance when sold at retailers. [7] The needs of the food and beverage industry can result in lower processing costs, more space, better efficiency, and lower equipment costs. [7] This may bring down the cost of food and beverages for consumers; even alcoholic beverages that are subject to hidden sin taxes.
Hydrofuel can be used to move heavy duty transports, trains, earth-moving equipment (including bulldozers), in addition to providing fuel to most boats and ships. [7] Reduced pollution and increased fuel efficiency may come out of nanoreactor-produced hydrofuel. [7] The increased usage of renewable energy may also help to improve the world's environment thanks to nanoreactors. [7]
Roy, Skinner, et al. studied the dynamics of water in self-assembled gemini surfactants in 2014. [8] This work illustrates not only the utility of nano-scale materials for chemical reactions, but also the complexity that is required to study the effects. The team utilized spectroscopic techniques and molecular dynamics simulations to determine that within the nanoporous structures, the dynamics of water in the gyroid phase is an order of magnitude slower than in the bulk water. This result arises from the difference in curvature at the interfaces of the normal gyroid. When compared with water confined in a reverse spherical micelle of a sulfonate surfactant, the water exhibited faster dynamics. This complex behavior was postulated to have implications for future work in ion transport.
Carbon nanotubes have been a popular area of research, and specifically, single-walled carbon nanotubes provide unique surfaces for chemistry. Li, G and Fu, C et al. report on large changes to the Raman spectra by encapsulating sulfur in these single-walled carbon nanotubes. In an example of how confinement to such small spaces influences chemistry, the authors theorize that the changes to the Raman spectra can be attributed to van der Waals interactions of the sulfur with the walls of the nanotubes. These effects are highly sensitive to the size of the confinement chamber, as the van der Waals interactions were not significant for larger diameter single-walled nanotubes. The authors suggest that confinement within the single-walled nanotubes allows S2 molecules to undergo polymerization to linear diradicals. [9]
Nanoreactors are also being applied to biological spaces. In a study by Tagliazucchi and Szleifer, they study the binding of proteins to ligands inside of both long nanochannels and short nanopores. Inside these confined spaces, the ligands are attached to the walls by polymeric tethers. This technology has already seen applications as sensors that measure concentrations of proteins in solution. This study developed a theory to model how the proteins bind under these highly confined conditions to inform the design of these sensors. [10]
Nanopore sequencing is a third generation approach used in the sequencing of biopolymers — specifically, polynucleotides in the form of DNA or RNA.
Resonance Raman spectroscopy is a variant of Raman spectroscopy in which the incident photon energy is close in energy to an electronic transition of a compound or material under examination. This similarity in energy (resonance) leads to greatly increased intensity of the Raman scattering of certain vibrational modes, compared to ordinary Raman spectroscopy.
A nanomotor is a molecular or nanoscale device capable of converting energy into movement. It can typically generate forces on the order of piconewtons.
Cadmium selenide is an inorganic compound with the formula CdSe. It is a black to red-black solid that is classified as a II-VI semiconductor of the n-type. It is a pigment, but applications are declining because of environmental concerns.
Aqueous biphasic systems (ABS) or aqueous two-phase systems (ATPS) are clean alternatives for traditional organic-water solvent extraction systems.
Molecular motors are natural (biological) or artificial molecular machines that are the essential agents of movement in living organisms. In general terms, a motor is a device that consumes energy in one form and converts it into motion or mechanical work; for example, many protein-based molecular motors harness the chemical free energy released by the hydrolysis of ATP in order to perform mechanical work. In terms of energetic efficiency, this type of motor can be superior to currently available man-made motors. One important difference between molecular motors and macroscopic motors is that molecular motors operate in the thermal bath, an environment in which the fluctuations due to thermal noise are significant.
In the context of chemistry, molecular physics, physical chemistry, and molecular modelling, a force field is a computational model that is used to describe the forces between atoms within molecules or between molecules as well as in crystals. Force fields are a variety of interatomic potentials. More precisely, the force field refers to the functional form and parameter sets used to calculate the potential energy of a system on the atomistic level. Force fields are usually used in molecular dynamics or Monte Carlo simulations. The parameters for a chosen energy function may be derived from classical laboratory experiment data, calculations in quantum mechanics, or both. Force fields utilize the same concept as force fields in classical physics, with the main difference being that the force field parameters in chemistry describe the energy landscape on the atomistic level. From a force field, the acting forces on every particle are derived as a gradient of the potential energy with respect to the particle coordinates.
Methane monooxygenase (MMO) is an enzyme capable of oxidizing the C-H bond in methane as well as other alkanes. Methane monooxygenase belongs to the class of oxidoreductase enzymes.
Enzyme catalysis is the increase in the rate of a process by a biological molecule, an "enzyme". Most enzymes are proteins, and most such processes are chemical reactions. Within the enzyme, generally catalysis occurs at a localized site, called the active site.
Nanofluidics is the study of the behavior, manipulation, and control of fluids that are confined to structures of nanometer characteristic dimensions. Fluids confined in these structures exhibit physical behaviors not observed in larger structures, such as those of micrometer dimensions and above, because the characteristic physical scaling lengths of the fluid, very closely coincide with the dimensions of the nanostructure itself.
Self-assembling peptides are a category of peptides which undergo spontaneous assembling into ordered nanostructures. Originally described in 1993, these designer peptides have attracted interest in the field of nanotechnology for their potential for application in areas such as biomedical nanotechnology, tissue cell culturing, molecular electronics, and more.
Carbon nanotube chemistry involves chemical reactions, which are used to modify the properties of carbon nanotubes (CNTs). CNTs can be functionalized to attain desired properties that can be used in a wide variety of applications. The two main methods of CNT functionalization are covalent and non-covalent modifications.
A carbon nanothread is a sp3-bonded, one-dimensional carbon crystalline nanomaterial. The tetrahedral sp3-bonding of its carbon is similar to that of diamond. Nanothreads are only a few atoms across, more than 300,000 times thinner than a human hair. They consist of a stiff, strong carbon core surrounded by hydrogen atoms. Carbon nanotubes, although also one-dimensional nanomaterials, in contrast have sp2-carbon bonding as is found in graphite. The smallest carbon nanothread has a diameter of only 0.2 nanometers, much smaller than the diameter of a single-wall carbon nanotube.
Water shortages have become an increasingly pressing concern recently and with recent predictions of a high probability of the current drought turning into a megadrought occurring in the western United States, technologies involving water treatment and processing need to improve. Carbon nanotubes (CNT) have been the subject of extensive studies because they demonstrate a range of unique properties that existing technologies lack. For example, carbon nanotube membranes can demonstrate higher water flux with lower energy than current membranes. These membranes can also filter out particles that are too small for conventional systems which can lead to better water purification techniques and less waste. The largest obstacle facing CNT is processing as it is difficult to produce them in the large quantities that most of these technologies will require.
Suzanne A. Blum is an American professor of chemistry at the University of California, Irvine. Blum works on mechanistic chemistry, most recently focusing on borylation reactions and the development of single-molecule and single-particle fluorescence microscopy to study organic chemistry and catalysis. She received the American Chemical Society's Arthur C. Cope Scholar Award in 2023.
Dr. Dan Thomas Major is a Professor of Chemistry at Bar Ilan University specializing in Computational Chemistry.
An Artificial Metalloenzyme (ArM) is a designer metalloprotein, not found in nature, which can catalyze desired chemical reactions. Despite fitting into classical enzyme categories, ArMs also have potential in new-to-nature chemical reactivity like catalysing Suzuki coupling, Metathesis etc., which were never reported among natural enzymatic reactions.
Mei Hong is a Chinese-American biophysical chemist and professor of chemistry at the Massachusetts Institute of Technology. She is known for her creative development and application of solid-state nuclear magnetic resonance (ssNMR) spectroscopy to elucidate the structures and mechanisms of membrane proteins, plant cell walls, and amyloid proteins. She has received a number of recognitions for her work, including the American Chemical Society Nakanishi Prize in 2021, Günther Laukien Prize in 2014, the Protein Society Young Investigator award in 2012, and the American Chemical Society’s Pure Chemistry award in 2003.
Julia A. Kovacs is an American chemist specializing in bioinorganic chemistry. She is professor of chemistry at the University of Washington. Her research involves synthesizing small-molecule mimics of the active sites of metalloproteins, in order to investigate how cysteinates influence the function of non-heme iron enzymes, and the mechanism of the oxygen-evolving complex (OEC).
Katsumi Kaneko was born in Yokohama (Kanagawa), Japan. He graduated with a Bachelor of Engineering degree in 1969 from Yokohama National University, Yokohama. He received a master's degree in physical chemistry at The University of Tokyo, in 1971. He received Doctor of Science in solid state chemistry in 1978 for submitted thesis from The University of Tokyo, entitled “Electrical Properties and Defect Structures of Iron Hydroxide Oxide
