Organic Phosphorescence
In article number 2502611, Shuzo Hirata and colleagues explain the selective through-bonds interactions between group 16 element and p framework in orbitals deeper in energy than the highest occupied molecular orbital selectively enhance the long-wavelength phosphorescence rate, enabling high-resolution multicolor afterglow bioimaging.
A NIR-II fluorescence-traced metal-phenolic nanosensitizer was developed that performed H2S-reprogrammed oxygen metabolism for radiotherapy intensification and immunogenicity. Hf-PSP-DTC@PLX nanoparticles generate H2S under an acidic tumor microenvironment to inhibit mitochondrial respiration and reprogram oxygen metabolism for tumor oxygenation. The chelated Hf ions simultaneously make full use of the preserved oxygen to improve the generation of local reactive oxygen species against tumor cells and to trigger antitumor immune activation.
Radiotherapy (RT) is hampered by the limited oxygen in tumors, which could be potentiated via reprogramming the oxygen metabolism and increasing the oxygen utilization efficiency. Herein, a metal-phenolic nanosensitizer (Hf-PSP-DTC@PLX) was integrated via an acid-sensitive hydrogen sulfide (H2S) donor (polyethylene glycol-co-polydithiocarbamates, PEG-DTC) and a hafnium-chelated polyphenolic semiconducting polymer (Hf-PSP) in an amphiphilic polymer (poloxamer F127, PLX). Hf-PSP-DTC@PLX elicited a high imaging performance for precise RT and generated H2S to reduce the cellular oxygen consumption rate via mitochondrial respiration inhibition, which reprogrammed the oxygen metabolism for improvement of the tumor oxygenation. Then, Hf-sensitization could fully utilize the well-preserved oxygen to intensify RT efficacy and activate immunogenicity. Such a synergistic strategy for improvement of oxygenation and oxygen utilization would have great potential in optimizing oxygen-dependent therapeutics.
Navigating tethered instruments through the vasculatures to reach deeper physiological locations presently inaccessible would extend the applicability of many medical interventions, including but not limited to local diagnostics, imaging, and therapies. Navigation through narrower vessels requires minimizing the diameter of the instrument, resulting in a decrease of its stiffness until steerability becomes unpractical, while pushing the instrument at the insertion site to counteract the friction forces from the vessel walls caused by the bending of the instrument. To reach beyond the limit of using a pushing force alone, we report a method relying on a complementary directional pulling force at the tip created by gradients resulting from the magnetic fringe field emanating outside a clinical magnetic resonance imaging (MRI) scanner. The pulling force resulting from gradients exceeding 2 tesla per meter in a space that supports human-scale interventions allows the use of smaller magnets, such as the deformable spring as described here, at the tip of the instrument. Directional forces are achieved by robotically positioning the patient at predetermined successive locations inside the fringe field, a method that we refer to as fringe field navigation (FFN). We show through in vitro and in vivo experiments that x-ray–guided FFN could navigate microguidewires through complex vasculatures well beyond the limit of manual procedures and existing magnetic platforms. Our approach facilitated miniaturization of the instrument by replacing the torque from a relatively weak magnetic field with a configuration designed to exploit the superconducting magnet-based directional forces available in clinical MRI rooms.
Nature Reviews Cancer, Published online: 14 June 2019; doi:10.1038/s41568-019-0166-0
Trifunctional antibodies, binding to the natural killer cell receptors NKp46 and CD16, as well as a tumour antigen, show promising activity in preclinical experiments.Probing matter with light in the mid-infrared provides unique insight into molecular composition, structure, and function with high sensitivity. However, laser spectroscopy in this spectral region lacks the broadband or tunable light sources and efficient detectors available in the visible or near-infrared. We overcome these challenges with an approach that unites a compact source of phase-stable, single-cycle, mid-infrared pulses with room temperature electric field–resolved detection at video rates. The ultrashort pulses correspond to laser frequency combs that span 3 to 27 μm (370 to 3333 cm–1), and are measured with dynamic range of >106 and spectral resolution as high as 0.003 cm–1. We highlight the brightness and coherence of our apparatus with gas-, liquid-, and solid-phase spectroscopy that extends over spectral bandwidths comparable to thermal or infrared synchrotron sources. This unique combination enables powerful avenues for rapid detection of biological, chemical, and physical properties of matter with molecular specificity.
Nature Reviews Materials, Published online: 24 May 2019; doi:10.1038/s41578-019-0123-2
Good chemistry between proteins and materialsDesigning a low-cost human-machine interface with specific function and desirable performance characteristics.
The post 3D Printing Enables Enhanced Human-Machine Interfaces appeared first on Advanced Science News.
Defined nanostructures: Block copolymer coated nanoparticles can be assembled into linear arrays and superlattices with 2‐, 3‐, and 6‐fold rotational symmetry. The type of superlattice is determined by the nanoparticle/domain size ratio and the block copolymer grafting density. This general and versatile method can be applied for a variety of metal, semiconducting, and magnetic nanoparticles.
The defined assembly of nanoparticles (NPs) in polymer matrices is an important prerequisite for next‐generation functional materials. A promising approach to control NP positions in polymer matrices at the nanometer scale is the use of block copolymers. It allows the selective deposition of NPs in nanodomains, but the final defined and ordered positioning of the NPs within the domains has not been possible. This can now be achieved by coating NPs with block copolymers. The self‐assembly of block copolymer‐coated NPs directly leads to ordered microdomains containing ordered NP arrays with exactly one NP per unit cell. By variation of the grafting density, the inter‐nanoparticle distance can be controlled from direct NP surface contact to surface separations of several nanometers, determined by the thickness of the polymer shell. The method can be applied to a wide variety of block copolymers and NPs and is thus suitable for a broad range of applications.
Publication date: Available online 11 May 2019
Source: Journal of Controlled Release
Author(s): Christine Allen
A cationic fluorescent nanogel thermometer based on thermo-responsive N-isopropylacrylamide and environment-sensitive benzothiadiazole was developed with a new azo compound bearing imidazolium rings as the first cationic radical initiator. This cationic fluorescent nanogel thermometer showed an excellent ability to enter live mammalian cells in a short incubation period (10 min), a high sensitivity to temperature variations in live cells (temperature resolution of 0.02-0.84 °C in the range 2040 °C), and remarkable non-cytotoxicity, which permitted ordinary cell proliferation and even differentiation of primary cultured cells.
Although transition metal dichalcogenide MoSe2 is recognized as one of the low-cost and efficient electrocatalysts for the hydrogen evolution reaction (HER), its thermodynamically stable basal plane and semiconducting property still hamper the electrocatalytic activity. Here, it is demonstrated that the basal plane and edges of 2H-MoSe2 toward HER can be activated by introducing dual-native vacancy. The first-principle calculations indicate that both the Se and Mo vacancies together activate the electrocatalytic sites in the basal plane and edges of MoSe2 with the optimal hydrogen adsorption free energy (ΔGH*) of 0 eV. Experimentally, 2D MoSe2 nanosheet arrays with a large amount of dual-native vacancies are fabricated as a catalytic working electrode, which possesses an overpotential of 126 mV at a current density of 100 mV cm−2, a Tafel slope of 38 mV dec−1, and an excellent long-term durability. The findings pave a rational pathway to trigger the activity of inert MoSe2 toward HER and also can be extended to other layered dichalcogenide.
Dual-native-vacancy (Mo and Se vacancies) in MoSe2 nanosheets are proved through experimental and first-principles study. Herein, dual-native-vacancy can activate the hydrogen evolution reaction (HER) activity of both basal plane and edges in MoSe2, guaranteeing its efficient HER catalysis. Meanwhile, dual-native-vacancy in the MoSe2 can enhance the conductivity of MoSe2 basal plane to promote rapid charge transfer over catalytic electrode.
This Minireview focuses on the Lewis acidity/basicity “umpolung” of boron-based nucleophiles and phosphorus-based electrophiles.
Basically acidic: In the Lewis acidity/basicity “umpolung”, elements that traditionally exhibit acidity or basicity are modified to behave as Lewis bases or acids, respectively. This inversion of reactivity provides significant synthetic challenges, but also provides uniquely reactive species as demonstrated by recent attention on boron-based nucleophiles and phosphorus-based electrophiles.
EXPERIMENTAL self-driving cars continue to make regular forays onto the roads. After a trial in Pittsburgh, Uber, a taxi-hailing-app company, launched several of its “autonomous” vehicles onto the streets of San Francisco on December 14th—and promptly ran into a row with officials for not obtaining an operating permit, which Uber insists is unnecessary as the vehicles have a backup driver to take over if something goes wrong. General Motors said it would begin testing self-driving cars in Michigan. For these and other trials one thing is essential: providing the vehicles with a reliable form of vision.
As no man-made system can yet match a pair of human eyes and the image-processing power of a brain, compromises have to be made. This is why engineers use a belt-and-braces approach in equipping vehicles with sensors that can scan the road ahead. That way, just as your trousers will stay up if one or other of belt and braces fails, if one system misses a potential hazard, such as an oncoming car or a pedestrian, the others might spot it and direct the car to take evasive action.
Three of the sensory systems currently in use...
