This work provides a benchmark for the future design and development of a new generation of smart sequence-selective supramolecular G4-binders that combine outstanding sensing and stability properties, to be utilized in anti-cancer therapy.We report on a series of 4-azidobenzyloxy-substituted self-immolative linkers which undergo [3 + 2]-cycloaddition (click reaction) with functionalized trans-cyclooctenes (TCOs) at second-order rate constants in the range of 0.017 to 4.9 M-1 s-1. The choice of 4-azidobenzyloxy-substituted linker and the TCO play a critical role in the rate of all click-and-release steps, which includes the [3 + 2]-cycloaddition and subsequent degradation pathway of the triazoline to an aniline that undergoes 1,6- or 1,8-self-immolation of the phenol. We demonstrate that reacting a 4-azido-2,3,5,6-tetrafluorobenzyloxy-linker with a highly strained TCO (d-TCO) gives, to the best of our knowledge, the fastest TCO-strained alkene-azide click reaction to date (4.9 M-1 s-1), but with one caveat; release of phenol via 1,6-self-immolation is extremely slow. A methyl substituent attached to the benzyl carbon of this analogue maintains the rapid click-reaction rate, but has the added benefit of enabling the release of the phenol within hours. https://www.selleckchem.com/products/gne-7883.html In an aqueous solvent at reagent concentrations in the micromolar range a maximium release was observed after 48 hours; ≈65 and ≈78% of phenol released depending on the TCO used. The new suite of linkers and their combination with TCOs of varying structure add to the toolbox of bioorthogonal click-and-release reactions.Snake venom is a complex mixture mainly consisting of proteins and peptides which varies with different species. These variations lead to different toxic mechanisms and different anti-venom serums for treatment and the determination of their use as drugs. Hence, it is important to develop a sensitive and reliable method to identify the species of snakes from venoms. Herein, we present a novel strategy based on the sheathless capillary electrophoresis-electrospray ionization-mass spectrometry (CESI-MS) system to characterize snake venom proteins. Through the determination of peptides, we found the characteristic peptides of 8 different snakes with high sensitivity (1 μg mL-1) and high selectivity, which provided a reliable method for the species identification and purity detection of snake venom samples.The twisted plywood structure as found in crustacean shells possesses excellent mechanical properties with high stiffness and toughness. Synthetic mimics can be produced by evaporation-induced self-assembly of cellulose nanocrystals (CNCs) with polymer components into bulk films with a cholesteric liquid crystal structure. However, these are often excessively brittle and it has remained challenging to make materials combining high stiffness and toughness. Here, we describe self-assembling cholesteric CNC/polymer nanocomposites with a crustacean-mimetic structure and tunable photonic band gap, in which we engineer combinations of thermo-activated covalent and supramolecular hydrogen-bonded crosslinks to tailor the energy dissipation properties by precise molecular design. Toughening occurs upon increasing the polymer fractions in the nanocomposites, and, critically, combinations of both molecular bonding mechanisms lead to a considerable synergetic increase of stiffness and toughness - beyond the common rule of mixtures. Our concept following careful molecular design allows one to enter previously unreached areas of mechanical property charts for cholesteric CNC-based nanocomposites. The study shows that the subtle engineering of molecular energy dissipation units using sophisticated chemical approaches enables efficient enhancing of the properties of bioinspired CNC/polymer nanocomposites, and opens the design space for future molecular enhancement using tailor-made interactions.Criegee Intermediates (CI), formed in the ozonolysis of alkenes, play a central role in tropospheric chemistry as an important source of radicals, with stabilised CI (SCI) able to participate in bimolecular reactions, affecting climate through the formation of inorganic and organic aerosol. However, total SCI yields have only been determined for a few alkene systems, while speciated SCI yields from asymmetrical alkenes are almost entirely unknown. Here we report for the first time a systematic experimental exploration of the stabilisation of CH2OO and (CH3)2COO CI, formed from ten alkene-ozone systems with a range of different sizes and structures, under atmospherically relevant conditions in the EUPHORE chamber. Experiments in the presence of excess SO2 (an SCI scavenger) determined total SCI yields from each alkene-ozone system. Comparison of primary carbonyl yields in the presence/absence of SO2 determined the stabilisation fraction of a given CI. The results show that the stabilisation of a given CI increases as the size of the carbonyl co-product increases. This is interpreted in terms of the nascent population of CI formed following decomposition of the primary ozonide (POZ) having a lower mean energy distribution when formed with a larger carbonyl co-product, as more of the energy from the POZ is taken by the carbonyl. These findings have significant implications for atmospheric modelling of alkene ozonolysis. Higher stabilisation of small CI formed from large alkenes is expected to lead to lower radical yields from CI decomposition, and higher SCI concentrations, increasing the importance of SCI bimolecular reactions.To date, plasmonic nanowire lasers mostly adopt hybrid plasmonic waveguides, while there is a lack of study in terms of the confinement effect and the corresponding ultrafast dynamics of non-hybridized plasmonic lasers. Here, we report ultrafast plasmonic nanowire lasers composed of a single CH3NH3PbBr3 nanowire on a silver film without any insulating layer at room temperature. The non-hybridized plasmonic nanowire lasers exhibit ultrafast lasing dynamics with around 1.9 ps decay rate and 1 ps peak response time. Such values are among the best ones ever reported. Interestingly, the threshold of the non-hybridized plasmonic nanowire lasers is in the same order as that of their hybrid counterparts. The low threshold is due to the ultra-flat single-crystal silver films and high-quality single-crystal perovskite nanowires. The non-hybridized plasmonic lasing in CH3NH3PbBr3 nanowires originates from the stimulated emission of an electron-hole plasma based on our experiments. This work deepens the understanding of non-hybridized plasmonic lasers and paves the way to design electric pump plasmonic lasers by getting rid of insulating layers.
This work provides a benchmark for the future design and development of a new generation of smart sequence-selective supramolecular G4-binders that combine outstanding sensing and stability properties, to be utilized in anti-cancer therapy.We report on a series of 4-azidobenzyloxy-substituted self-immolative linkers which undergo [3 + 2]-cycloaddition (click reaction) with functionalized trans-cyclooctenes (TCOs) at second-order rate constants in the range of 0.017 to 4.9 M-1 s-1. The choice of 4-azidobenzyloxy-substituted linker and the TCO play a critical role in the rate of all click-and-release steps, which includes the [3 + 2]-cycloaddition and subsequent degradation pathway of the triazoline to an aniline that undergoes 1,6- or 1,8-self-immolation of the phenol. We demonstrate that reacting a 4-azido-2,3,5,6-tetrafluorobenzyloxy-linker with a highly strained TCO (d-TCO) gives, to the best of our knowledge, the fastest TCO-strained alkene-azide click reaction to date (4.9 M-1 s-1), but with one caveat; release of phenol via 1,6-self-immolation is extremely slow. A methyl substituent attached to the benzyl carbon of this analogue maintains the rapid click-reaction rate, but has the added benefit of enabling the release of the phenol within hours. https://www.selleckchem.com/products/gne-7883.html In an aqueous solvent at reagent concentrations in the micromolar range a maximium release was observed after 48 hours; ≈65 and ≈78% of phenol released depending on the TCO used. The new suite of linkers and their combination with TCOs of varying structure add to the toolbox of bioorthogonal click-and-release reactions.Snake venom is a complex mixture mainly consisting of proteins and peptides which varies with different species. These variations lead to different toxic mechanisms and different anti-venom serums for treatment and the determination of their use as drugs. Hence, it is important to develop a sensitive and reliable method to identify the species of snakes from venoms. Herein, we present a novel strategy based on the sheathless capillary electrophoresis-electrospray ionization-mass spectrometry (CESI-MS) system to characterize snake venom proteins. Through the determination of peptides, we found the characteristic peptides of 8 different snakes with high sensitivity (1 μg mL-1) and high selectivity, which provided a reliable method for the species identification and purity detection of snake venom samples.The twisted plywood structure as found in crustacean shells possesses excellent mechanical properties with high stiffness and toughness. Synthetic mimics can be produced by evaporation-induced self-assembly of cellulose nanocrystals (CNCs) with polymer components into bulk films with a cholesteric liquid crystal structure. However, these are often excessively brittle and it has remained challenging to make materials combining high stiffness and toughness. Here, we describe self-assembling cholesteric CNC/polymer nanocomposites with a crustacean-mimetic structure and tunable photonic band gap, in which we engineer combinations of thermo-activated covalent and supramolecular hydrogen-bonded crosslinks to tailor the energy dissipation properties by precise molecular design. Toughening occurs upon increasing the polymer fractions in the nanocomposites, and, critically, combinations of both molecular bonding mechanisms lead to a considerable synergetic increase of stiffness and toughness - beyond the common rule of mixtures. Our concept following careful molecular design allows one to enter previously unreached areas of mechanical property charts for cholesteric CNC-based nanocomposites. The study shows that the subtle engineering of molecular energy dissipation units using sophisticated chemical approaches enables efficient enhancing of the properties of bioinspired CNC/polymer nanocomposites, and opens the design space for future molecular enhancement using tailor-made interactions.Criegee Intermediates (CI), formed in the ozonolysis of alkenes, play a central role in tropospheric chemistry as an important source of radicals, with stabilised CI (SCI) able to participate in bimolecular reactions, affecting climate through the formation of inorganic and organic aerosol. However, total SCI yields have only been determined for a few alkene systems, while speciated SCI yields from asymmetrical alkenes are almost entirely unknown. Here we report for the first time a systematic experimental exploration of the stabilisation of CH2OO and (CH3)2COO CI, formed from ten alkene-ozone systems with a range of different sizes and structures, under atmospherically relevant conditions in the EUPHORE chamber. Experiments in the presence of excess SO2 (an SCI scavenger) determined total SCI yields from each alkene-ozone system. Comparison of primary carbonyl yields in the presence/absence of SO2 determined the stabilisation fraction of a given CI. The results show that the stabilisation of a given CI increases as the size of the carbonyl co-product increases. This is interpreted in terms of the nascent population of CI formed following decomposition of the primary ozonide (POZ) having a lower mean energy distribution when formed with a larger carbonyl co-product, as more of the energy from the POZ is taken by the carbonyl. These findings have significant implications for atmospheric modelling of alkene ozonolysis. Higher stabilisation of small CI formed from large alkenes is expected to lead to lower radical yields from CI decomposition, and higher SCI concentrations, increasing the importance of SCI bimolecular reactions.To date, plasmonic nanowire lasers mostly adopt hybrid plasmonic waveguides, while there is a lack of study in terms of the confinement effect and the corresponding ultrafast dynamics of non-hybridized plasmonic lasers. Here, we report ultrafast plasmonic nanowire lasers composed of a single CH3NH3PbBr3 nanowire on a silver film without any insulating layer at room temperature. The non-hybridized plasmonic nanowire lasers exhibit ultrafast lasing dynamics with around 1.9 ps decay rate and 1 ps peak response time. Such values are among the best ones ever reported. Interestingly, the threshold of the non-hybridized plasmonic nanowire lasers is in the same order as that of their hybrid counterparts. The low threshold is due to the ultra-flat single-crystal silver films and high-quality single-crystal perovskite nanowires. The non-hybridized plasmonic lasing in CH3NH3PbBr3 nanowires originates from the stimulated emission of an electron-hole plasma based on our experiments. This work deepens the understanding of non-hybridized plasmonic lasers and paves the way to design electric pump plasmonic lasers by getting rid of insulating layers.
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