Valence‐Engineering of Quantum Dots Using Programmable DNA Scaffolds

Precise control over the valency of quantum dots (QDs) is critical and fundamental for quantitative imaging in living cells. However, prior approaches on valence control of QDs remain restricted to single types of valences. A DNA‐programmed general strategy is presented for valence engineering of QDs with high modularity and high yield. By employing a series of programmable DNA scaffolds, QDs were generated with tunable valences in a single step with near‐quantitative yield (>95 %). The use of these valence‐engineered QDs was further demonstrated to develop 12 types of topologically organized QDs‐QDs and QDs‐AuNPs and 4 types of fluorescent resonance energy transfer (FRET) nanostructures. Quantitative analysis of the FRET nanostructures and live‐cell imaging reveal the high potential of these nanoprobes in bioimaging and nanophotonic applications.     

A General Strategy for Development of Near‐Infrared Fluorescent Probes for Bioimaging

Near‐infrared (NIR) fluorescent dyes with favorable photophysical properties are highly useful for bioimaging, but such dyes are still rare. The development of a unique class of NIR dyes via modifying the rhodol scaffold with fused tetrahydroquinoxaline rings is described. These new dyes showed large Stokes shifts (>110 nm). Among them, WR3, WR4, WR5, and WR6 displayed high fluorescence quantum yields and excellent photostability in aqueous solutions. Moreover, their fluorescence properties were tunable by easy modifications on the phenolic hydroxy group. Based on WR6, two NIR fluorescent turn‐on probes, WSP‐NIR and SeSP‐NIR, were devised for the detection of H₂S. The probe SeSP‐NIR was applied in visualizing intracellular H₂S. These dyes are expected to be useful fluorophore scaffolds in the development of new NIR probes for bioimaging.     

Abscheidung von Kohlendioxid: Perspektiven für neue Materialien

Der stark ansteigende Kohlendioxidgehalt in der Atmosphäre ist eines der drängendsten Umweltprobleme unserer Zeit. Eine Option zur Verringerung anthropogener CO₂‐Emissionen ist die Abscheidung und Speicherung von Kohlendioxid (Carbon Capture and Storage, CCS) an Punktquellen wie Kraftwerken. Durch diese Sequestrierung steigt allerdings der Energiebedarf der Kraftwerke um 25–40 %. Wir berichten hier über die Technologien zur Abscheidung, die zur Verringerung der CO₂‐Emissionen wahrscheinlich am besten geeignet sind. Dazu zählen Postcombustion‐Verfahren, bei denen die Abscheidung nach der Verbrennung stattfindet (vor allem die CO₂/N₂‐Separation), Precombustion‐Verfahren, bei denen CO₂/H₂‐Gemische eingesetzt werden, und die Konditionierung von Erdgas (CO₂/CH₄). Der Schlüssel zu deutlichen Fortschritten sind bessere Trennmittel zur Separation. Wir werden hier aktuelle Entwicklungen und neuartige Konzepte zur CO₂‐Abtrennung durch Lösungsmittel‐Absorption, chemische und physikalische Adsorption und Membranen schildern und besonders auf Fortschritte auf dem wachsenden Gebiet Metall‐organischer Gerüste eingehen.     

Controllable Modular Growth of Hierarchical MOF‐on‐MOF Architectures

Fabrication of hybrid MOF‐on‐MOF heteroarchitectures can create novel and multifunctional platforms to achieve desired properties. However, only MOFs with similar crystallographic parameters can be hybridized by the classical epitaxial growth method (EGM), which largely suppressed its applications. A general strategy, called internal extended growth method (IEGM), is demonstrated for the feasible assembly of MOFs with distinct crystallographic parameters in an MOF matrix. Various MOFs with diverse functions could be introduced in a modular MOF matrix to form 3D core–satellite pluralistic hybrid system. The number of different MOF crystals interspersed could be varied on demand. More importantly, the different MOF crystals distributed in individual domains could be used to further incorporate functional units or enhance target functions.