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    General Chemistry

    Biomimetic hydrogel with photodynamic antimicrobial effect

    Infections are a dreaded threat that can have fatal consequences after an operation, in the treatment of wounds, and during tissue engineering. Biomimetic hydrogels with “built-in” antimicrobial properties can significantly decrease this danger. In the journal Angewandte Chemie, scientists have now introduced a gel that is activated by red light to produce reactive oxygen compounds that effectively kill bacteria and fungi. …read more

    Source:: PhysOrg Chemistry

          

    Potassium-driven rechargeable batteries: An effort toward a more sustainable environment

    Our modern lifestyle would be immensely different without rechargeable batteries. Owing to their low-cost, recyclable technology, these batteries are used in most portable electronic devices, electric and hybrid vehicles, and renewable power generation systems. They offer an elegant solution to the world’s growing energy demands. Moreover, rechargeable batteries are an essential tool in systems that harvest renewable energy, such as the wind and sunlight, because these sources can fluctuate greatly with the weather. Rechargeable batteries store generated electricity and dispatch it on demand. Thus, researchers globally have been focused on improving rechargeable batteries as a step toward sustainable energy resources. …read more

    Source:: PhysOrg Chemistry

          

    Bridging Ultrasmall Au Clusters into the Pores of a Covalent Organic Framework for Enhanced Photostability and Photocatalytic Performance

    Gold (Au) clusters loading on various supports were widely used in the fields of energy and biology. However, the poor photostability of Au clusters on support interface under longtime illumination usually results in loss of catalytic performance. Covalent organic frameworks (COFs ) with periodic and ultrasmall pore structures are ideal supports for dispersing and stabilizing Au clusters, while it is difficult to encapsulate Au clusters into the ultrasmall pore structures. Herein, a two‐dimensional (2D) COF modified with thiol chains (‐SH) in its pores was prepared. Taking ‐SH as nucleation sites, Au NCs can in situ grow within the COF. Ultrasmall pore structure of COF and the strong binding energy of S‐Au provide double assurance for improving the dispersibility of Au NCs under longtime light illumination conditions. Interestingly, the artificial Z‐scheme photocatalytic system was constructed due to the form of Au‐S‐COF bonding bridge, which is deemed to be an ideal means to increase the charge separation efficiency. Such new strategy provides a facile guideline for rationally designing COF support catalysts with controllable activity and high stability.

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    Source:: Angewandte Chemie Int. edition

          

    Light‐harvesting nanoparticle probes for FRET‐based detection of oligonucleotides with single‐molecule sensitivity

    Controlling emission of bright luminescent nanoparticles by a single molecular recognition event remains an ultimate challenge in the design of ultrasensitive probes for biomolecules. It would require an efficient Förster resonance energy transfer (FRET) from the nanoparticle to a single acceptor at its surface, which is not realized to date. Here, we developed 20‐nm light‐harvesting nanoantenna particles, built of a tailor‐made hydrophobic charged polymer poly(ethyl methacrylate‐co‐methacrylic acid), encapsulating ~1000 strongly coupled and highly emissive rhodamine dyes with their bulky counterion. Being 87‐fold brighter than quantum dots QDots605 in single‐particle microscopy (with 550‐nm excitation), these DNA‐functionalized nanoparticles exhibit >50% total FRET efficiency to a single hybridized FRET acceptor, a highly photostable carbopyronine dye (ATTO665). The obtained FRET nanoprobes enable single‐molecule detection of short DNA and RNA, encoding a cancer marker, and imaging single hybridization events by an epi‐fluorescence microscope with ultralow excitation irradiance close to ambient sunlight.

    …read more

    Source:: Angewandte Chemie Int. edition

          

    Amphiphilic Polyphenylene Dendron Conjugates for Surface Remodeling of Adenovirus 5

    The arrangement of amphiphilic surface groups plays an important role in many biological processes such as protein folding or biorecognition. We report the synthesis of amphiphilic polyphenylene dendrimer branches (dendrons) providing alternating hydrophilic and lipophilic surface groups and one reactive enthynyl group at the core. The amphiphilic surface groups serve as biorecognition units that bind to the surface of adenovirus 5 (Ad5), which is one of the most common vectors in gene therapy. The Ad5/dendron complexes showed high gene transduction efficiencies in coxsackie‐adenovirus receptor (CAR)‐negative cells. Moreover, the dendrons offer incorporating new functions at the dendron core by in situ post‐modifications even when bound to the Ad5 surface. In this way, we provide a new platform for introducing bioactive groups to the Ad5 surface without the necessity to chemically modify the virus particles. Moreover, we analyzed binding of blood proteins to surfaces coated with amphiphilic dendrons, which is essential to predict their performance in the blood stream and of high relevance for in vivo applications.

    …read more

    Source:: Angewandte Chemie Int. edition

          

    Designing 0D/2D S‐scheme Heterojunction over Polymeric Carbon Nitride for Visible‐Light Photocatalytic Inactivation of Bacteria

    Constructing heterojunctions between two semiconductors with matched band structure is one of the most effective strategies to acquire high‐efficiency photocatalysts. S‐scheme heterojunction system, as an innovative photocatalytic system, has shown great potential in facilitating separation and transfer of photogenerated carriers, as well as acquiring strong photoredox ability. Herein, a 0D/2D S‐scheme heterojunction material involving CeO 2 quantum dots and polymeric carbon nitride (CeO 2 /PCN) is designed and constructed via in‐situ wet chemistry with subsequent heat treatment. This S‐scheme heterojunction material shows high‐efficiency photocatalytic sterilization rate (88.1%) towards Staphylococcus Aureus (S.aureus) under visible‐light irradiation (λ ≥ 420 nm), which is 2.7 and 8.2 times that of pure CeO 2 (32.2%) and PCN (10.7%), respectively. Strong evidence of S‐scheme charge transfer path is verified by theoretical calculation, in‐situ irradiated X‐ray photoelectron spectroscopy (ISI‐XPS), and electron paramagnetic resonance (EPR) analyses. This work provides a robust way for tailoring the performance and interpreting the mechanism of heterojunction‐based photocatalytic system for high‐performance photocatalysis.

    …read more

    Source:: Angewandte Chemie Int. edition

          

    Researchers gain control over internal structure of self-assembled composite materials

    Composites made from self-assembling inorganic materials are valued for their unique strength and thermal, optical and magnetic properties. However, because self-assembly can be difficult to control, the structures formed can be highly disordered, leading to defects during large-scale production. Researchers at the University of Illinois and the University of Michigan have developed a templating technique that instills greater order and gives rise to new 3-D structures in a special class of materials, called eutectics, to form new, high-performance materials. …read more

    Source:: PhysOrg Chemistry

          

    Predicting the year in chemistry

    With 2020 just starting, scientists around the world are wondering what the year has in store for them. To help steer them straight, Chemical & Engineering News (C&EN), the weekly newsmagazine of the American Chemical Society, is highlighting key business and policy issues that will impact the chemistry enterprise across the globe. …read more

    Source:: PhysOrg Chemistry

          

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