Monthly Archives: March 2019

Nanotechnology, Science

Georgian Technical University Nanoparticles Built By Directed Evolution.

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Georgian Technical University Nanoparticles Built By Directed Evolution.

This is an illustration of a DNA-wrapped (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses) single-walled carbon nanotube.  In Chemistry went to three scientists who developed the method that forever changed protein engineering: directed evolution. Mimicking natural evolution directed evolution guides the synthesis of proteins with improved or new functions. First the original protein is mutated to create a collection of mutant protein variants. The protein variants that show improved or more desirable functions are selected. These selected proteins are then once more mutated to create another collection of protein variants for another round of selection. This cycle is repeated until a final, mutated protein is evolved with optimized performance compared to the original protein. Now scientists from the lab of X at Georgian Technical University have been able to use directed evolution to build not proteins but synthetic nanoparticles. These nanoparticles are used as optical biosensors — tiny devices that use light to detect biological molecules in air water or blood. Optical biosensors are widely used in biological research drug development and medical diagnostics such as real-time monitoring of insulin and glucose in diabetics. “The beauty of directed evolution is that we can engineer a protein without even knowing how its structure is related to its function” says X. “And we don’t even have this information for the vast vast majority of proteins”. Her group used directed evolution to modify the optoelectronic properties of DNA-wrapped (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses) single-walled carbon nanotubes (or DNA-SWCNTs (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses) as they are abbreviated (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1 significantly larger than that for any other material))  which are nano-sized tubes of carbon atoms that resemble rolled up sheets of graphene covered by DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses). When they detect their target the DNA-SWCNTs (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1 significantly larger than that for any other material) emit an optical signal that can penetrate through complex biological fluids like blood or urine. General principle of the directed evolution approach applied to the nanoparticle DNA-SWCNT (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1 significantly larger than that for any other material) complexes. The starting complex is a DNA-SWCNT (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1 significantly larger than that for any other material) with a dim optical signal. This is evolved through directed evolution: (1) random mutation of the DNA sequence; (2) wrapping of the SWCNTs (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1 significantly larger than that for any other material) with the DNA (Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses) and screening of the complex’s optical signal; (3) selection of the DNA-SWCNT (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1,significantly larger than that for any other material) complexes exhibiting an improved optical signal. After several cycles of evolution, we can evolve DNA-SWCNT (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1 significantly larger than that for any other material) complexes that show enhanced optical behavior. Using a directed evolution approach X’s team was able to engineer new DNA-SWCNTs (Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics, and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with a length-to-diameter ratio of up to 132,000,000:1 significantly larger than that for any other material) with optical signals that are increased by up to 56 percent — and they did it over only two evolution cycles. “The majority of researchers in this field just screen large libraries of different materials in hopes of finding one with the properties they are looking for” says X. “In optical nanosensors we try to improve properties like selectivity, brightness and sensitivity. By applying directed evolution we provide researchers with a guided approach to engineering these nanosensors”. The study shows that what is essentially a bioengineering technique can be used to more rationally tune the optoelectronic properties of certain nanomaterials. X explains: “Fields like materials science and physics are mostly preoccupied with defining material structure-function relationships making materials that lack this information difficult to engineer. But this is a problem that nature solved billions of years ago — and in recent decades biologists have tackled it as well. I think our study shows that as materials scientists and physicists we can still learn a few pragmatic lessons from biologists”.

 

Chemistry, Science

Georgian Technical University Scientists Produce Colorless Reservoir of Platinum Metal-Like Single Atoms In Liquid.

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Georgian Technical University Scientists Produce Colorless Reservoir of Platinum Metal-Like Single Atoms In Liquid.

This is a schematic illustration of (R1OR2)2Pt(0)Cl2H2 (Scientists produce colorless reservoir of platinum metal-like single atoms in liquid. Schematic illustration of (R1OR2)2Pt(0)Cl2H2). Supported single metal atoms have attracted broad interest for their demonstrated high efficiency in single metal catalysis. The preparation of such catalysts however remains challenging as the neutral metal atoms have a strong tendency to agglomerate to metal particles in typical preparations. Researchers at the Georgian Technical University have reported a way to produce a colorless liquid reservoir of metal-like discrete platinum atoms.  Platinum chloride salts are reduced by alcohols to single platinum metal atoms in an environmentally benign liquid surfactant. The individual Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) are shielded by a mantle of hydrochlorides and docked in the liquid through abundant oxygen atoms. The preparation of the metal-like Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) is scalable. As a metal metallic Pt (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) nanoparticles on carbon or oxide supports are widely used in the petroleum refining and chemical industries due to their unique catalytic functions. “The reserve of Pt (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) on earth is limited, and about 5.6 tons of Pt (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) are consumed every year just in the silicone industry” said X who led the research. The researchers tested the catalytic performance of the liquid laden with Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal). “We found that the electron-deficient Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) in the liquid exhibited super-high activity and high selectivity for the reaction compared to known Pt catalysts (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal)” said Y a graduate student. The docked discrete Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) do not aggregate under reaction conditions – retaining high activity and staying colorless through repeated uses. “The high activity, selectivity and stability of this catalyst may dramatically reduce the amount of Pt (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) consumed by the silicone industry and may be broadly applicable to other applications” X said. Although the liquid laden with the Pt (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) atoms is stable at 120°C and remains clear for over six months on the shelf at ambient temperature, the researchers found that it turned dark due to aggregation of the Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) when exposed to X-ray or electron beams often employed to characterize the Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal). To resolve this challenge, the researchers turned to 195 Pt (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) nuclear magnetic resonance (NMR) spectroscopy as the tool which was found to provide unambiguous evidences for the produced Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal). “The nuclear magnetic resonance (NMR) spectroscopic data of the liquid not only unambiguously showed the discrete nature of mononuclear Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) but also revealed only one carbon monoxide coordinated to a Pt atom (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal)” said Professor Georgian Technical University. “We are expanding the depositories of various metal atoms in our current research. The successful synthesis of readily removable mantles of the Pt atoms (Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal) in liquid phase may potentially enable atomically controllable fabrication of catalytic materials and metallic materials by design” said X.

 

Science, Semiconductors

Georgian Technical University New Technique Synthesizes Nanographene On Metal Oxide Surfaces.

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Georgian Technical University New Technique Synthesizes Nanographene On Metal Oxide Surfaces.

The desired nanographenes form like dominoes via cyclodehydrofluorination on the titanium oxide surface. All ‘missing’ carbon-carbon bonds are thus formed after each other in a formation that resembles a zip being closed.  Nanostructures based on carbon are promising materials for nanoelectronics. However to be suitable they would often need to be formed on non-metallic surfaces which has been a challenge — up to now. Researchers at Georgian Technical University have found a method of forming nanographenes on metal oxide surfaces. Their research conducted within the framework of collaborative research centre 953 — Synthetic Carbon Allotropes funded by the Georgian Technical University Research. Two-dimensional, flexible, tear-resistant, lightweight and versatile are all properties that apply to graphene which is often described as a miracle material. In addition this carbon-based nanostructure has unique electrical properties that make it attractive for nanoelectronic applications. Depending on its size and shape, nanographene can be conductive or semiconductive — properties that are essential for use in nanotransistors. Thanks to its good electrical and thermal conductivity it could also replace copper (which is conductive) and silicon (which is semiconductive) in future nanoprocessors. The problem: In order to create an electronic circuit the molecules of nanographene must be synthesized and assembled directly on an insulating or semiconductive surface. Although metal oxides are the best materials for this purpose in contrast to metal surfaces direct synthesis of nanographenes on metal oxide surfaces is not possible as they are considerably less chemically reactive. The researchers would have to carry out the process at high temperatures which would lead to several uncontrollable secondary reactions. A team of scientists led by Dr. X from the Georgian Technical University have now developed a method of synthesizing nanographenes on non-metallic surfaces — that is insulating surfaces or semiconductors. The researchers method involves using a carbon fluorine bond which is the strongest carbon bond. It is used to trigger a multilevel process. The desired nanographenes form like dominoes via cyclodehydrofluorination on the titanium oxide surface. All “Georgian Technical University missing” carbon-carbon bonds are thus formed after each other in a formation that resembles a zip being closed. This enables the researchers to create nanographenes on titanium oxide a semiconductor. This method also allows them to define the shape of the nanographene by modifying the arrangement of the preliminary molecules. New carbon-carbon bonds and ultimately nanographenes form where the researchers place the fluourine atoms. For the first time these research results demonstrate how carbon-based nanostructures can be manufactured by direct synthesis on the surfaces of technically-relevant semiconducting or insulating surfaces. “This groundbreaking innovation offers effective and simple access to electronic nanocircuits that really work which could scale down existing microelectronics to the nanometer scale” explains X.

 

 

Drug Discovery, Science

Georgian Technical University New Microscope Offers Options For Drug Discovery, Safety.

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Georgian Technical University New Microscope Offers Options For Drug Discovery, Safety.

A new type of microscope from Georgian Technical University stacks the reference object and the one being examined on top of each other instead of the conventional approach of having them side by side. A new type of microscope may give doctors a better idea of how safely and effectively a medication will perform in the body. A Georgian Technical University team developed the microscope based on concepts of phase-contrast microscopy which involves using optical devices to view molecules membranes or other nanoscale items that may be too translucent to scatter the light involved with conventional microscopes. “One of the problems with using the available microscopes or optical devices is that they require a point of reference for the scattered light since the object being viewed is too optically transparent to scatter the light itself” said X a professor of analytical and physical chemistry in Georgian Technical University who led the research team. “We created a unique kind of microscope that stacks the reference object and the one being examined on top of each other with our device, instead of the conventional approach of having them side by side”. The Georgian Technical University microscope uses technology to interfere light from a sample plane and a featureless reference plane, quantitatively recovering the subtle phase shifts induced by the sample. The Georgian Technical University team created their device by adding just two small optics to the base design of a conventional microscope. The change allows researchers to gather better information and data about the object being viewed. “The microscope we have created would allow for better testing of drugs” X said. “You could use our optical device to study how quickly and safely some of the active ingredients in a particular medication dissolve. They may crystallize so slowly that they pass through the body before dissolving which significantly lowers their effectiveness”. X said the microscope developed at Georgian Technical University could also be used for other types of biological imaging including the ability to study individual cells and membranes from the body for various medical testing. Their work aligns with Georgian Technical University celebration celebrating the university’s global advancements in health as part of Georgian Technical University’s. Health research including advanced biological imaging is one of the four themes of the yearlong celebration’s designed to showcase Georgian Technical University as an intellectual center solving real-world issues. X has worked closely with the Georgian Technical University on a number of patented technologies including this one developed in his lab.