Applications and studies in DNA-based biophysics, biochemistry and biotechnology rely on accurate imaging with high temporal and spatial resolution towards the mesoscopic and single-molecule levels. This, in turn, relies on the ability to immobilize and stretch portions of DNA on a substrate without damaging it. Researchers in Italy have now reported a noninvasive, all-optical, holographic technique for permanently aligning liquid crystalline DNA filaments in a microperiodic template realized in soft-composite materials.
Researchers are very interested in investigating the biomechanical properties of the inner structure of cells due to their relevance in many important topics in biology such as intracellular and intercellular dynamics; tissue and organs formation and their homeostasis; but also in medicine as the formation and development of diseases like inflammatory disorders or tumor. In order to study inner cell properties, researchers have now presented a biophotonic holographic workstation that combines the complementary features of holographic optical tweezers (HOT) and self-interference digital holographic microscopy, in order to investigate biomechanics properties at the single cell level.
Fluidic force microscopy (FluidFM) is an emerging technology which combines atomic force microscopy (AFM) with microfluidics. In a new study, researchers in Switzerland have now developed an innovative method for straightforward injection into the nucleus of a living cell, taking advantage of the nanoscale accuracy and small probe size of AFM and the possibility to handle fluid under pressure-control through the integrated microchannel.
Optical tweezers offer researchers the chance to perform precise force sensing in a fluid environment. This could help to give clarity to some of the picoNewton forces that govern fundamental processes in the cell. However, currently the use of tweezers to probe biological, samples requires either direct irradiation with a laser, or the use of a tool or proxy to exert or sense very small forces. There are many instances when exposing samples to high intensity laser light is less than ideal - typically this is within a biological context. Researchers have now have shown that optical tweezers can be combined with naturally derived algae to create a stable nanoscale optical force sensor. This may enable other groups to utilize this technique to probe key force interactions that occur at the lowest end of the nanoscale force regime.
One of the key issues in the development of novel nanomedicines is the ability to track nanoscale drug carriers inside the body to evaluate where they go and how they get there. Virtually all previous preclinical studies in this area of research rely on 2D Fluorescence Reflectance Imaging (FRI). Given the limitation of 2D FRI in not being able to detect the fluorescence in deep-seated organs and tissues, 3D Fluorescence Molecular Tomography (3D FMT) emerged as an alternative. However, the lack of anatomical information was an important barrier hindering the routine use of standard 3D FMT for in vivo imaging of nanomedicines. Researchers have now developed a hybrid CT-FMT-based imaging protocol to enable more meaningful and more quantitative in vivo analyses.
Nanostructured surfaces with special wetting properties can not only efficiently repel or attract liquids like water and oils but can also prevent formation of biofilms, ice, and other detrimental crystals. Such super- and ultrahydrophobic surfaces also hold the promise of significantly improving performance of condensers, which could boost the efficiency of most power plants in the world. A critical part of designing such surfaces is 'seeing' how water and other liquids interact when in contact with them. Since these surfaces are made of nanostructures, scientists need to use an electron microscope to image these interactions. In new work, researchers have developed a method for directly imaging such interfacial regions with previously unattainable nanoscale resolution.
Doping, the process of adding impurity atoms to semiconductors to provide free carriers for conduction, has been pivotal to microelectronics since its early stages. In particular doping germanium at high concentrations to make it highly conductive is the subject of intense research, because it lies at the heart of novel developments in integrated silicon-compatible lasers and quantum information processing devices. Researchers have now demonstrated a method to densely pack dopant molecules on the germanium surface, which then self-organize to form molecular patterns with one phosphorus dopant atom every two germanium atoms. The key finding is that when you deposit phosphine molecules on a germanium surface, they naturally form molecular patterns with one phosphorus atom every two germanium atoms that densely pack the surface.
Researchers have demonstrated that electrons in nanoscale networks can behave like car drivers in congested cities. Traffic planners are sometimes faced with a rather counter-intuitive observation - adding a new road to a congested road network can lead to a deterioration of the overall traffic situation, i.e. longer trip times for individual road users. Or, in reverse, blocking certain streets in a complex road network can counter-intuitively reduce congestion. This has become known as the Braess paradox. Researchers have now applied the concept of the Braess paradox to the quantum world. By combining quantum simulations of a model system and scanning-probe experiments, they have shown that an analogue of the Braess paradox can occur in mesoscopic semiconductor networks, where electron transport is governed by quantum mechanics. The paradox manifests itself by an increase of the conductance network when one arm in the network is partially blocked in a controlled manner.