A very promising field of nanomotor research are DNA nanomachines. These are synthetic DNA assemblies that switch between defined molecular shapes upon stimulation by external triggers. They can be controlled by a variety of methods that include pH changes and the addition of other molecular components, such as small molecule effectors, proteins and DNA strands. Researchers have now designed and built a simple DNA machine that is capable of continuous rotation with controlled speed and direction - a function that might be very useful for example for molecular transport. This machine is driven by an externally controlled electric field. When this field is oscillated between four directions, it continuously reorients a rotor DNA that is asymmetrically attached to a DNA axle.
In many biomedical applications, protein nanotubes present several advantages over nanospheres. The layer-by-layer (LbL) deposition technique for the preparation of protein nanotubes has attracted considerable attention because of their potential nanotechnology applications in enzymatic nanocatalysts, bioseparation nanofilters, and targeting nanocarriers. A drawback is that in template synthesis the extraction process often results in physical deformation of the nanotubes. Researchers in Japan have now developed a new procedure using specific solvent and freeze-drying technique. They describe for the first time molecular capturing properties of protein nanotubes with a controllable affinity and size selectivity.
Proteins are the most important molecules inside our body. There are thousands of proteins in a single cell alone and they control our physiological reactions, metabolism, cellular information flow, defense mechanisms - pretty much everything. No wonder then that most human diseases are related to the malfunctioning of particular proteins. In contrast to gene therapy - where a gene is placed inside a cell to either replace a defective gene or to increase the amount of a specific gene in order to produce a higher amount of a desired protein - protein therapy works by directly delivering well-defined and precisely structured proteins into the cell to replace the dysfunctional protein. The problem with protein therapy, which limits its practical use in medicine, is the mode of delivery. Scientists have now demonstrated a general, effective, low-toxicity intracellular protein delivery system based on single-protein nanocapsules.
After two decades of evolution, Atomic Force Microscopy (AFM) has established its strong existence in the material science research field with its nanoscale resolution. Of the systems out in the market, the innovative XE-AFMs have overcome the non-linearity and non-orthogonality problems associated with traditional piezoelectric tube based AFMs. Active in both research and industrial applications including hard-disk, microchip fabrication, and quality control, the XE series has been widely adopted in the nanometrology field. The most recent addition to the XE family, the XE-Bio, has integrated the high resolution of AFM imaging and non-invasiveness capabilities Scanning Ion Conductance Microscopy with the versatility of advanced optical microscopy techniques such as scanning confocal microscopy, FRET and TIRF. Therefore, the XE-Bio is able to correlate the highest possible spatial resolution with dynamic functionality studies on live biological samples.
A group of researchers from Singapore, led by Professor Dingyuan Tang from Nanyang Technological University and Professor Kian Ping Loh from National University of Singapore, have reported the first breakthrough in using few-layer graphene as a saturable absorber for the mode locking of lasers. Despite its prominent mechanical and electrical properties, graphene's optical response has previously been considered to be weak and featureless, so the main interests of the research community are centered on its electronics properties. But now, Tang and Loh demonstrate that graphene can be used for telecommunications applications and that its weak and universal optical response might be turned into advantages for ultrafast photonics applications.
One challenge in designing nanomachines is being able to establish how well they work and optimize their performance. This is where single molecule techniques will play an important role. With advances in nanotechnologies, it is possible to construct simple nanomachines that can perform simple functions such as opening and closing of a DNA device (e.g. DNA tweezers or DNA switches), small rotational and translational motors and energy transfer cascades. Using single-molecule techniques researchers can watch individual nanomachines working and determine the functionality of their design. Researchers in Germany now have incorporated optical addressability to these nanomachines. Hence, they can optically detect and eventually control the state of the nanodevice.
No other element in the periodic table bonds to itself in an extended network with the strength of the carbon-carbon bond. This special nature of carbon, combined with the molecular perfection of single-walled nanotubes endows these nanotubes with exceptional material properties, such as very high electrical and thermal conductivity, strength, stiffness, and toughness. As a result, single-walled carbon nanotubes (SWCNTs) are the strongest material known to science. SWCNTs potentially can add incredible strength, stiffness and electrical conductivity to all kinds of composite materials. Unfortunately, they are always held together in rope form due to their extremely small dimension and van der Waals attraction and their strength can neither be exploited nor measured. However, if several SWCNTs are concentrically nested in a confined space, the sliding issue can be resolved and the SWCNTs may share the applied tensile load to realize nanometer-scale materials remarkably stronger than the individual SWCNTs.
Much of today's genetic research and diagnostics uses tools and technologies enabled by DNA's ability to bind to its complementary strand in a sequence specific manner. For biologists studying molecular mechanisms inside cells, this information helps to quantify the expression levels of genes. Detection of the binding - or hybridization - of DNA strands is at the heart of modern medicine. The technology for detecting DNA hybridization mainly relies on the use of fluorescent labels. The complementary strand coming from the sample bears a label, so detection of florescence signal indicates hybridization. While this may sound straightforward, it has major limitations. Researchers have now reported a new technique for genetic analysis using nanomechanical response of hybridized DNA/RNA molecules. This new technique is several orders of magnitude more sensitive than other approaches and it is a lot simpler to use.