Chemistry

Luminescent carbon nanoparticles based on carbon exhibit advantageous optical properties. They are also biocompatible, and therefore better suited for imaging procedures in the biosciences than metal-based semiconductor quantum dots. A variety of processes have thus been developed to make these miniature objects known as carbon dots or C-dots. Chinese researchers have now introduced a new method in the journal Angewandte Chemie, by which C-dots can be produced particularly quickly and inexpensively. In addition, they have demonstrated the use of these luminescent dots as printer ink.

In living systems, complex nano- and microscale structures perform a host of physical and biological functions. While two-dimensional patterns can be recreated fairly well with techniques like microlithography, three-dimensional structures represent a big challenge. In the journal Angewandte Chemie, American researchers have now reported a new method for the lithography-free etching of complex surface motifs with the use of biodegradable polymers and enzymes. Starting with structured microchannels, they have built an assembly for the isolation and concentration of cells from whole blood.

Highly sensitive and highly selective tests are important for the early detection of disease, the detection of environmental toxins, or for the detection of explosives at airports. Increased selectivity for the target analytes helps to avoid false-positive results. In the journal Angewandte Chemie, Indian scientists have now introduced a specific detection method for the explosive TNT that can be used to detect even a single molecule.

Writing in the journal Drug Testing and Analysis, American researcher’s state the argument that marijuana is a harmless drug is no longer valid due to the emergence of ‘high potency’ marijuana and synthetic marijuana which pose a potential real threat for pregnant women.

Gold is not just the material of choice for pretty jewelry; it is also used in technology, for example in nanoscopic particles for applications such as catalysis, biomedicine, and sensors. In the journal Angewandte Chemie, a team of American and Chinese researchers has now demonstrated that the morphology of gold nanoparticles can be controlled when they are synthesized in the presence of DNA. Depending on the DNA sequence used, the shape and surface roughness can be varied.

To reduce fossil fuel consumption while simultaneously improving the carbon footprint of fuels and chemical products, the use of carbon dioxide as a carbon source could be an attractive option. In the journal Angewandte Chemie, German researchers have now introduced a method by which carbon dioxide can be catalytically hydrogenated to make formic acid. In this process, carbon dioxide is not only a starting material; it also acts—in a supercritical state—as the solvent for separation of the product. This integrated approach makes it possible to directly obtain free formic acid as the product in a single step for the first time.

Fingerprints are not just important in forensics and the identification of people; they can also be used for security clearance, access control, and the authentication of documents. In the journal Angewandte Chemie, Chinese researchers have now introduced a new fast method to make fingerprints visible at high resolution.

Fossil-based resources are declining and their use releases the greenhouse gas CO₂. Both of these problems could be significantly mitigated if we could use CO₂ as a carbon source for the production of fuels and chemical feedstocks. Various different approaches are currently being explored for the catalytic conversion of CO₂ to methanol (CH₃OH). In the journal Angewandte Chemie, German researchers have now introduced a new possibility to conduct this stepwise reaction of CO₂ in solution with help of a homogeneous catalyst.

Gram staining of bacteria is a routine diagnostic method of long standing that can be used for initial diagnoses and to simplify the choice of antibiotics. It is a simple way to classify bacteria into two classes—Gram-positive and Gram-negative—under a microscope. In the journal Angewandte Chemie, American researchers have now introduced an improvement to this method: magnetic Gram staining. This allows for the class-specific, automated, magnetic detection and separation of bacteria.

Why does “fetid fluorite”, a mineral that is found in the Upper Palatinate in Bavaria, Germany, have such an unpleasant sharp smell when it is crushed? Scientists in Munich have now found the solution to this puzzle, not only bringing an end to a controversial discussion that has been going on for about 200 years, but also altering a hard and fast textbook rule. In the journal Angewandte Chemie, the researchers have demonstrated that the stench is caused by elemental fluorine. This unambiguously proves that despite prior assumptions, elemental fluorine does occur in nature.

Our electronic devices are getting smaller and smaller while doing more and more. Using conventional materials, we will soon reach the practical limit. The electronics of tomorrow require alternatives, such as nanowires made of DNA that can serve as conductive paths and nanotransistors for miniature circuits. In the journal Angewandte Chemie, German scientists have now described a new method for the production of stable, conducting DNA nanowires.

Microscopically small submarines that can swim through our blood to clear out clogged arteries or destroy malignant tumors. This concept may sound utopian, but it isn’t. Various micro- and nanomachines have in fact already been developed. In the journal Angewandte Chemie, American researchers have now introduced a new type of machine that finally has enough propulsive power to penetrate tissue and overcome cellular barriers.

Wiley annouces the publication of the only reference available that gives a thorough overview of all the important current methods used in Physical Chemistry.

Complex laboratory investigations do produce reliable results, but they are not useful for point-of-care diagnostics. This is especially true in developing countries, which must rely on simple, inexpensive test methods that do not require a power source. Biosensors based on paper are an interesting alternative. American researchers from the University of Texas at Austin and the University of Illinois at Urbana-Champaign have now introduced a particularly clever concept in the journal Angewandte Chemie: print on one side of the paper, fold it up origami-style, laminate it, and the test is ready. Test evaluation requires only a voltmeter.

The ultimate handbook on microcirculation imaging techniques

During photosynthesis, plants capture solar energy and use it to drive chemical reactions. Their carbon source is the CO₂ in air. In the journal Angewandte Chemie, American scientists have now proposed a new reaction mechanism that binds CO₂ and strongly resembles photosynthesis. In this process, light energy is captured by silicon nanowires. It was successfully used to synthesize two precursors of the anti-inflammatory, pain reducing drugs ibuprofen and naproxen.

Many discoveries are made by chance, but it is also possible to help it along: The chance of finding something interesting increases when the number of experiments rises. French researchers have now applied this principle to the search for new chemical reactions. In the journal Angewandte Chemie, they have introduced a new concept based on antibodies and a “sandwich” immunoassay.