A chip-scale device that both produces and detects a specialized gas used in biomedical analysis and medical imaging has been built and demonstrated at the National Institute of Standards and Technology (NIST). The new microfluidic chip produces polarized (or magnetized) xenon gas and then detects even the faintest magnetic signals from the gas.
Polarized xenon, with the atoms’ nuclear “spins” aligned like bar magnets in the same direction, can be dissolved in liquids and used to detect the presence of certain molecules. A chemical interaction with target molecules subtly alters the magnetic signal from the xenon; by detecting this change researchers can identify the molecules in a complex mixture. Polarized xenon is also used as a contrast agent to enhance images in experimental magnetic resonance imaging (MRI) of human lungs, but conventional systems for producing and using this gas can be as big as a car.
Researchers from NIST and three other institutions developed the new chip, which might be used to reduce the size and cost of some instruments that, like MRI, rely on nuclear magnetic resonance (NMR). The chip’s sensitive internal detector boosts the response of microfluidic NMR on small samples and eliminates the need for the powerful magnets associated with larger NMR devices such as those used in MRI. The microfabricated chip could be mass produced and integrated easily with existing microfluidic systems.
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A new network grant has recently been approved in Europe, the TDCOST Action TD 1402: Multifunctional Nanoparticles for Magnetic Hyperthermia and Indirect Radiation Therapy (RADIOMAG)
The Action aims to bring together and to organise the research outcomes from the different participating network members in a practical way to provide clinicians with the necessary input to trial a novel anti-cancer treatment combining magnetic hyperthermia and radiotherapy, also identifying future research objectives upon appraisal of the obtained results. Feedback between the different working groups here is essential, and is expected that the lifetime of this Action proposal will eventually result in a compendium of best practices for magnetic hyperthermia.
RADIOMAG will generate new and strengthen the existing synergies between technical advances (thermal imaging / MH), new treatment concepts (combined targeting radiosensitisation and magnetic thermotherapy) and biocompatible coating in order to achieve a breakthrough in the clinical application of magnetic hyperthermia. Due to the complexity of this aim, synergies can only be achieved on a longer time frame, by means of workshops, STSMs, joint publications, common Horizon 2020 research proposals and exchange with other COST Actions (e.g. TD1004, TD1205).
The company Nanocomposix published a very good introduction into particle size measurement with dynamic light scattering (DLS) measurement. After analyzing thousands of nanoparticle samples they have assembled a set of guidelines that can be used to determine how to maximize the quality of your DLS data and, more importantly, how to interpret your results. Check it out here. And if you have more questions, contact them at firstname.lastname@example.org or (858) 565-4227 x 2.
The smallest robot worldwide is only a few micrometer long and has been created at ETH Zurich. The robot designed to be steered through the human body forces high design chal-lenges on the researchers in terms of control and power supply. It is inspired by the flagella of the E. coli bacteria, which allows highly efficient locomotion. The metallic replica of the flagella is set in rotation by an external magnetic field, whose direction and intensity can be regulated and adjusted according to the direction the robot should swim. The ETH spin-off Aeon Scientific is currently working on the marketing of the new control technology.
The toxicity of many drugs creates high risk of destroying healthy cells when attempting to treat disease. Scientists at ETH Zurich’s Institute of Robotics and Intelligent Systems (IRIS) have developed a tiny robot about a half-millimeter in diameter that may provide a solution. The robot comprises a star-shaped, bi-layer, soft hydrogel shell that, when closed, forms a sphere and holds tiny magnetic beads inside. When the robot reaches the desired loca-tion, laser irradiation causes the hydrogel to change shape and the capsule to open, delivering the drug. The hy-drogel robot has been tested only in-vitro, but the scientists believe they can miniaturize it enough to test it in ani-mals in the future.
In nature, magnetosomes—membrane-bound magnetic nanocrystals with unprecedented magnetic properties—can be biomineralized by magnetotactic bacteria, e.g., Magnetospirillum gryphiswaldense . However, these microbes are difficult to handle. Isabel Kolinko, Youming Zhang, Dirk Schüler et al. now were able to transfer a minimum set of genes for the biosynthetic pathway of biomineralization of magnetic nanoparticles from these fastidious microorganisms to Rhodospirillum rubrum, a gram negative proteobacterium. Biomineralization of highly ordered magnetic nanostructures was then possible and might in the future allow for the sustainable production of tailored magnetic nanostructures in biotechnologically relevant hosts. This represents a step towards the endogenous magnetization of various organisms by synthetic biology.
Check out the details in this interesting Nature Nanotechnology 9, 193-197 (2014) paper. It includes an editorial.
Microscopes able to image magnetic fields are an increasingly important tool, not only for material physics but also for industry where they are used to check the magnetic field of hard disk write heads. The NV center in diamond – an atomic-size color defect – is a promising candidate for the next generation of sensor heads for magnetic field microscopes. It can sense magnetic fields with high (nT) sensitivity and, more importantly, sub-nm resolution. This latter property is an order of magnitude better than existing techniques such as magnetic force microscopy.
Imaging of magnetic fields with NV centers has been demonstrated before, but has so far required sophisticated and error-prone control techniques (e.g. lock-in detection). Prof. Wachtrup in Stuttgart and his team now managed to radically simplify this technique with the help of a computer-optimized spectroscopy protocol based on a technique known as optimal control. His protocol switches off fluorescence of a scanning color center whenever the magnetic field reaches one of several magic values. Scanning through a spatially varying magnetic field, fluorescence of the center simultaneously images multiple contour lines of the magnetic field – lines where the field takes on one of the magic values. This pattern is visually and conceptually analogous to tree lines in biology, which – mathematically phrased – reveal all parts of a piece of wood that were grown by the tree at a particular instant in time. Technically, this contour line pattern can be used to quantitatively reconstruct a map of the full magnetic field, just as tree-rings can reveal the growth history of a tree.
The inventors demonstrated their technique by imaging a MFM-tip as an example of a magnetic nanostructure, gaining previously unknown insights into its magnetic field structure. It was then used to check different models of the MFM-tip's magnetic field for validity.
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Enming Zhang, Erik Renström, Martin Koch et al. examined whether the rotational nanoparticle movement could be used for remote induction of cell death by injuring lysosomal membrane structures - without magnetic hyperthermia. They further hypothesized that the shear forces created by the generation of oscillatory torques (incomplete rotation) of SPIONs bound to lysosomal membranes would cause membrane permeabilization, lead to extravasation of lysosomal contents into the cytoplasm, and induce apoptosis. To examine this experimentally, they covalently conjugated SPIONs with antibodies targeting the lysosomal protein marker LAMP1 (LAMP1-SPION).
Remote activation of slow rotation of LAMP1-SPIONs significantly improved the efficacy of cellular internalization of the nanoparticles. Furthermore, the magnetic nanoparticles induced both early and late apoptosis remotely. Dynamic magnetic field generation, which the authors termed DMF, might thus be an important platform technology for novel biomedical applications.
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