Polystyrene nanoparticles are generally considered nontoxic, but a new study by Michael Shuler, Gretchen Mahler et al now suggests that ingesting them can influence iron uptake and transport. There might be a mechanism by which ingested nanoparticles exert a subtle yet harmful effect. The researchers examined how carboxylated polystyrene particles just 50 nm in diameter behaved in an in vitro model of the human intestinal epithelium and in tests with live chickens given doses that mimic potential human exposure. Intestinal cells in the in vitro model showed increased iron transport because of disruptions to the cell membrane. Chickens with acute nanoparticle exposure had lower iron absorption than either unexposed or chronically exposed chickens. The researchers found that the villi—tiny projections in the intestinal walls—of chickens subjected to
chronic exposure remodeled themselves to increase the surface area for iron absorption.
Although people do not normally eat polystyrene nanoparticles, other nanoparticles commonly used as food additives (e.g., titanium dioxide and
silicates) might have similar effects.
Check out the details here.
Portable, low-cost and quantitative detection of a broad range of targets at home and in the field has the potential to revolutionize medical diagnostics and environmental monitoring. Taking advantage of the wide availability and low cost of the pocket-sized personal glucose meter—used worldwide by diabetes sufferers—Yu Xiang and Yi Lu demonstrate a method to use such meters to quantify non-glucose targets, ranging from a recreational drug (cocaine, 3.4 mM detection limit) to an important biological cofactor (adenosine, 18 mM detection limit), to a disease marker (interferon-gamma of tuberculosis, 2.6 nM detection limit) and a toxic metal ion (uranium, 9.1 nM detection limit). The method is based on the target-induced release of invertase from a functional-DNA–invertase conjugate bound to magnetic particles. The released invertase converts sucrose into glucose, which is detectable using a normal glucose meter. The approach should be easily applicable to the detection of many other targets through the use of suitable functional-DNA partners (aptamers DNAzymes or aptazymes).
Check the original Nature Chemistry article here.
A research team led by Julian Eastoe of England’s University of Bristol recently developed an iron-based surfactant that responds to a magnetic field. The researchers showed that their detergent, composed of an alkane chain with a cationic head group and a tetrachloroferrate(III) counterion (FeCl4–), is capable of being drawn from an aqueous phase through an organic solvent by a small magnet. With small-angle neutron scattering, the team also proved that in water, their magnetic surfactant forms small clusters called micelles. Conventional soaps and detergents also form these structures, which give the cleaners their functionality.
When asked why he and his team decided to try making a surfactant that’s switched on by a magnet, Eastoe says they were motivated by “good old-fashioned scientific curiosity.” There has to be a place for that type of inquiry
in science, he contends. To read more, check this Angewandte Chemie article here.
Sometime in 2011, a special issue about magnetic nanoparticles was published in two different journals, the International Journal of Molecular Sciences and the Materials journal. Professor Jon Dobson was the guest editor. Check it out! It is open access and can be accessed here:
Researchers from the Institute of Experimental Physics at the Slovak Academy of Sciences (IEP SAS) in Kosice are investigating the interaction of albumin-modified magnetic fluids with insulin amyloid aggregates. The research tackles complications associated with diabetes, where amyloid deposits (fibrils) can form in patients near the site of insulin injections. Results indicate that incubation of insulin amyloid fibrils with albumin-modified magnetic fluid leads to the significant destruction of aggregates. The extent of the depolymerizing activity was affected by the amount of albumin used for magnetic fluid modification and mainly depends on the size of nanoparticles.
The team's findings represent a starting point for the application of active albumin-modified magnetic fluids as therapeutic agents targeting insulin amyloidosis. For the original paper, check out this link.
Elena Rozhkova from Argonne National Lab wrote a nice review article on recent progress in the development of advanced nanoscale photoreactive, magnetic and multifunctional materials applicable to brain cancer diagnostics, imaging, and therapy, with an emphasis on the latest contributions and the novelty of the approach, along with the most promising emergent trends. Check it out here.
Nguyen TK Thanh at the Davy Faraday Research Laboratory, University College London and the Royal Institution, and colleagues, believe they have now a better way of tracking neural stem cells after a transplant over long periods of time. They have developed hollow biocompatible cobalt-platinum nanoparticles and attached them to the stem cells. The nanoparticles are stable for months and have a high magnetic moment - tendency to align with a magnetic field - so that low concentrations can be detected using magnetic resonance imaging (MRI).
The team labelled stem cells with biocompatible cobalt-platinum nanoparticles, injected them into spinal cord slices and took images of their progress over time. They found that low numbers of the nanoparticle-loaded stem cells could still be detected two weeks after transplantation. 'The new method demonstrates the feasibility of reliable, noninvasive MRI imaging of nanoparticle-labelled cells,' says Thanh.
Thanh hopes that her stem cell tracking method will be used during stem cell replacement therapy for many central nervous system diseases. Her team is working towards developing nanoparticles that can be used to diagnose and treat these diseases.
Microstructure is crucial to obtain very strong composite materials (e.g., teeth, bone and sea shell structures). Randall Erb, Andre Studart et al. at the Federal Institute of Technology in Zurich, Switzerland now published a method how to elegantly and easily do this in a low magnetic field of 1 to 10 milliTeslas.
Using micrometer-sized reinforcing particles coated with minimal concentrations of superparamagnetic nanoparticles (0.01 to 1 volume percent) synthetic composites with tuned three-dimensional orientation and distribution of reinforcements were produced. A variety of structures was achieved with this simple method, leading to composites with tailored local reinforcement, wear resistance, and shape memory effects.
See for yourself: Science 335, 199-204 (2012).
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