Lifeboat Foundation

One day soon, buildings could become more energy-efficient—and environmentally sustainable—with insulating material developed from wood by researchers in Sweden. The newly-developed material offers as good or even better thermal performance than ordinary plastic-based insulation materials, according to researchers reporting recently in ACS Applied Materials & Interfaces.

Yuanyuan Li, an assistant professor at Wallenberg Wood Science Center, KTH Royal Institute of Technology in Stockholm, says that the new insulating material is an aerogel integrated wood which is made without adding additional substances.

Wood cellulose aerogels themselves are nothing new—researchers have been developing advanced types of aerogels and other composites for the last several years in the Wallenberg Wood Science Center at KTH—but Li says the new method represents a breakthrough in controlled creation of insulating nanostructures in the pores of wood.

Using a network of vibrating nano-strings controlled with light, researchers from AMOLF have made sound waves move in a specific irreversible direction and attenuated or amplified the waves in a controlled manner for the first time. This gives rise to a lasing effect for sound. To their surprise, they discovered new mechanisms, so-called “geometric phases,” with which they can manipulate and transmit sound in systems where that was thought to be impossible. “This opens the way to new types of (meta)materials with properties that we do not yet know from existing materials,” says group leader Ewold Verhagen who, together with shared first authors Javier del Pino and Jesse Slim, publishes the surprising results on June 2 in Nature.

The response of electrons and other charged particles to magnetic fields leads to many unique phenomena in materials. “For a long time, we have wanted to know whether an effect similar to a magnetic field on electrons could be achieved on sound, which has no charge,” says Verhagen. “The influence of a magnetic field on electrons has a wide impact: for example, an electron in a magnetic field cannot move along the same path in the opposite direction. This principle lies at the basis of various exotic phenomena at the nanometer scale, such as the quantum Hall effect and the functioning of topological insulators (materials that conduct current perfectly at their edges and not in their bulk). For many applications, it would be useful if we could achieve the same for vibrations and sound waves and therefore break the symmetry of their propagation, so it is not time-reversal symmetric anymore.”

Aqueous droplet formation by liquid-liquid phase separation (or coacervation) in macromolecules is a hot topic in life sciences research. Of these various macromolecules that form droplets, DNA is quite interesting because it is predictable and programmable, which are qualities useful in nanotechnology. Recently, the programmability of DNA was used to construct and regulate DNA droplets formed by coacervation of sequence designed DNAs.

A group of scientists at Tokyo University of Technology (Tokyo Tech) led by Prof. Masahiro Takinoue has developed a computational DNA droplet with the ability to recognize specific combinations of chemically synthesized microRNAs (miRNAs) that act as biomarkers of tumors. Using these miRNAs as molecular input, the droplets can give a DNA logic computing output through physical DNA droplet phase separation. Prof. Takinoue explains the need for such studies, “The applications of DNA droplets have been reported in cell-inspired microcompartments. Even though biological systems regulate their functions by combining biosensing with molecular logical computation, no literature is available on integration of DNA droplet with molecular computing.” Their findings were published in Advanced Functional Materials.

Developing this DNA droplet required a series of experiments. First, they designed three types of Y-shaped DNA nanostructures called Y-motifs A, B, and C with 3 sticky ends to make A, B, and C DNA droplets. Typically, similar droplets band together automatically while to join dissimilar droplets a special “linker” molecule is required. So, they used linker molecules to join the A droplet with the B and C droplets; these linker molecules were called AB and AC linkers, respectively.

Mimicking the human body, specifically the actuators that control muscle movement, is of immense interest around the globe. In recent years, it has led to many innovations to improve robotics, prosthetic limbs and more, but creating these actuators typically involves complex processes, with expensive and hard-to-find materials.

Researchers at The University of Texas at Austin and Penn State University have created a new type of fiber that can perform like a muscle actuator, in many ways better than other options that exist today. And, most importantly, these muscle-like fibers are simple to make and recycle.

In a new paper published in Nature Nanotechnology (“Nanostructured block copolymer muscles”), the researchers showed that these fibers, which they initially discovered while working on another project, are more efficient, flexible and able to handle increased strain compared to what’s out there today. These fibers could be used in a variety of ways, including medicine and robotics.

Our cells perform a marvel of engineering when it comes to packing information into small spaces. Every time a cell divides, it bundles up an amazing 4 meters of DNA into 46 tiny packages, each of which is only several millionths of a meter in length. Researchers from EMBL Heidelberg and the Julius-Maximilians-Universität Würzburg have now discovered how a family of DNA motor proteins succeeds in packaging loosely arranged strands of DNA into compact individual chromosomes during cell division.

The researchers studied condensin, a protein complex critical to the process of chromosome formation. Although this complex was discovered more than three decades ago, its mode of action remained largely unexplored. In 2018, researchers from the Häring group at EMBL Heidelberg and their collaborators showed that condensin molecules create loops of DNA, which may explain how chromosomes are formed. However, the inner workings by which the protein complex achieves this feat remained unknown.

Continue reading “Uncovering the inner workings of the molecular machinery that shapes chromosomes during cell division” »

Researchers have developed nano-scale drills that kill bacteria by drilling holes into their membranes. They are powered by visible light.

A new technology is using particles of gold to make colors. With further work, the method developed at Aalto University could herald a new display technology.

The technique uses gold nanocylinders suspended in a gel. The gel only transmits certain colors when lit by polarized light, and the color depends on the orientation of the gold nanocylinders. In a clever twist, a collaboration led by Anton Kuzyk’s and Juho Pokki’s research groups used DNA molecules to control the orientation of gold nanocylinders in the gel.

“DNA isn’t just an information carrier—it can also be a building block. We designed the DNA molecules to have a certain melting temperature, so we could basically program the material,” says Aalto doctoral candidate Joonas Ryssy, the study’s lead author. When the gel heats past the melting temperature, the DNA molecules loosen their grip and the gold nanocylinders change orientation. When the temperature drops, they tighten up again, and the nanoparticles go back to their original position.

By Chuck Brooks

The rapid pace of technological change is clearly visible, but much of what you may not see, the exceedingly small physical components of change called nanotechnologies, are catalyzing the revolution.

Nanosheets are finely structured two-dimensional materials and have great potential for innovation. They are fixed on top of each other in layered crystals, and must first be separated from each other so that they can be used, for example, to filter gas mixtures or for efficient gas barriers. A research team at the University of Bayreuth has now developed a gentle, environmentally-friendly process for this difficult process of delamination that can even be used on an industrial scale. This is the first time that a crystal from the technologically attractive group of zeolites has been made usable for a broad field of potential applications.

The delamination process developed in Bayreuth under the direction of Prof. Dr. Josef Breu is characterized by the fact that the structures of the nanosheets isolated from each other remain undamaged. It also has the advantage that it can be used at normal room temperature. The researchers present their results in detail in Science Advances.

The two-dimensional nanosheets, which lie on top of each other in layered crystals, are held together by electrostatic forces. In order for them to be used for technological applications, the electrostatic forces must be overcome, and the nanosheets detached from each other. A method particularly suitable for this is osmotic swelling, in which the nanosheets are forced apart by water and the molecules and ions dissolved in it. So far, however, it has only been possible to apply it to a few types of crystals, including some clay minerals, titanates, and niobates. For the group of zeolites, however, whose nanosheets are highly interesting for the production of functional membranes due to their silicate-containing fine structures, the mechanism of osmotic swelling has not yet been applicable.