Low-Molecular-Weight, High-Mechanical-Strength, and Solution-Processable Telechelic Poly(ether imide) End-Capped with Ureidopyrimidinone

Solution-processable poly­(ether imide)­s (PEIs) with ureido­pyrimidinone (UPy) end groups were prepared by incorporating mono­isocyanato-6-methyl­isocytosine into amine-terminated PEI oligomers. After functionalization with UPy end groups, PEI with a molecular weight as low as 8 kDa (8k-PEI-UPy) can be solution-cast to form films. Tensile tests revealed that 8k-PEI-UPy had an outstanding Young’s modulus higher than those of state-of-the-art high-molecular-weight commercial PEIs. The tensile strength, maximum elongation, and Young’s modulus of 8k-PEI-UPy were 87.2 ± 10.8 MPa, 3.10 ± 0.39%, and (3.20 ± 0.14) × 10³ MPa, respectively. The discovery herein significantly advances the chemistry of high-temperature PEI resins. UPy-based supramolecular chemistry is an effective and general strategy to achieve outstanding mechanical properties for PEI oligomers

Target-Activating and Toehold Displacement Ag NCs/GO Biosensor-Mediating Signal Shift and Enhancement for Simultaneous Multiple Detection

Herein, we demonstrate that a new multicolor silver nanoclusters/graphene oxide (Ag NCs/GO) hybrid material, upon target response, undergoes a configuration transformation, based on entropy-driven enzyme-free toehold-mediated strand displacement reaction, achieving emission shift and enhancement. To realize the aim above, two different synthesis routes (route I and II) of synthesizing fluorescent Ag NCs for constructing toehold displacement Ag NCs/GO biosensor is designed and performed. Influenza A virus subtype genes (H1N1 and H5N1) as a model can efficiently initiate the operation of entropy-driven displacement reaction, resulting in activatable fluorescence. Red-emitting and green-emitting Ag NCs tethering the complementary sequence of H1N1 (pDNA1) and H5N1 (pDNA2) are indirectly immobilized on GO surface through binding with capture DNA (cDNA1 and cDNA2), respectively, forming multicolor pDNA-Ag NCs/GO nanohybrid materials. However, they do not exhibit nearly fluorescence signals attributed to energy transfer from donor Ag NCs to acceptor GO. Upon adding targets H1N1 and H5N1 (tDNA1 and tDNA2), pDNA1-Ag NCs and pDNA2-Ag NCs detach from GO, based on toehold-mediated strand displacement reaction, which interferes the energy transfer and leads to significant fluorescence enhancement. More interestingly, the activatable process is accompanied by remarkable hypsochromic shift (19 nm) or bathochromic shift (21 nm) emission with quite high fluorescence recovery rates (823.35% and 693.62%). Therefore, based on these phenomena, a novel multiple approach has been developed with the assistance of toehold displacement and Ag NCs/GO nanohybrid materials. As for the remarkable emission recovery and multichannel signal, the proposed approach displays the promising application prospect in accurate diagnosis and treatment

Key Parameter Controlling the Sensitivity of Plasmonic Metal Nanoparticles: Aspect Ratio

Currently the synthesis of plasmonic nanoparticles for sensing applications mostly focuses on their shape because it is believed that nanoparticles with sharp tips provide higher sensitivities than those without. Herein, by measuring and analyzing the sensitivities of more than 74 types of nanoparticles of various shapes, sizes, and compositions, we found that, contrary to this common belief, the correlation between shape and sensitivity is much weaker than that between aspect ratio and sensitivity. Among all the parameters investigated here, including size, shape, composition, aspect ratio, cross-sectional area, and initial plasmonic resonance frequency, the aspect ratio (R) is the key parameter that controls the nanoparticle sensitivity (S) following an empirical equation, S = 46.87R + 109.37. Other parameters have much less influence on the nanoparticle sensitivity to refractive index changes. The stronger dependence of the sensitivity on aspect ratio than on shape encourages us to reassess the current focus of nanoparticle synthesis chemistry. In addition, the S–R linear relationship determined here can be used as a design rule for future synthesis and fabrication of highly sensitive nanomaterials for chemical, biological, biomedical, and environmental sensing

Supplemental Material4 - Supplemental material for Propylene glycol alginate sodium sulphate attenuates LPS-induced acute lung injury in a mouse model

Supplemental material, Supplemental Material4 for Propylene glycol alginate sodium sulphate attenuates LPS-induced acute lung injury in a mouse model by Peng Zhao, Guoliang Liu, Yunfeng Cui and Xufang Sun in Innate Immunity</p

Coordination Environment Dependent Surface Cu State for CO₂ Hydrogenation to Methanol

Catalytic conversion of CO2 with green hydrogen produced from renewable sources into methanol is one of the promising ways to cycle waste CO2 for carbon neutralization. The activity of Cu-based catalysts for methanol synthesis is closely related to the chemical environment of Cu species, which can be modulated by the special structure of MOFs. It is desired to elucidate the relationship between coordination environment of MOFs and chemical state of confined active metal (e.g., Cu). Herein, we regulate the surface Cu state by changing the coordination environment of copper in MOF-derived catalysts (Cu@UiO-66 and Cu@UiO-66-NH2). It is found that Cu species in the fresh Cu@UiO-66 catalyst occupy defect sites coordinated by carboxyl groups while being complexed by amino groups in Cu@UiO-66-NH2. Combined with XPS and in situ DRIFTS spectra, we find that the Cu@UiO-66 precursor facilitates the formation of Cu+-ZrO2 interfaces upon in situ activation, while Cu@UiO-66-NH2 favors the generation of metallic Cu sites. The catalytic results show that the methanol space-time yield of Cu@UiO-66 reaches 2.86 g gCu–1 h–1, which is 1.7 times that of Cu@UiO-66-NH2 and 6.0 times that of commercial Cu/ZnO/Al2O3 under the same conditions (260 °C, 1 MPa). The Cu@UiO-66 catalyst also shows good stability for 100 h in a time-on-stream test. We believe that the superior activity of Cu@UiO-66 is attributed to the formation of abundant Cu+-ZrO2 interfacial sites as active sites for methanol synthesis from CO2/H2

Supplemental Material1 - Supplemental material for Propylene glycol alginate sodium sulphate attenuates LPS-induced acute lung injury in a mouse model

Supplemental material, Supplemental Material1 for Propylene glycol alginate sodium sulphate attenuates LPS-induced acute lung injury in a mouse model by Peng Zhao, Guoliang Liu, Yunfeng Cui and Xufang Sun in Innate Immunity</p

In Situ Construction of a Coordination Zirconocene Tetrahedron

The current study describes the first in situ synthesis and characterization of a new family of cationic coordination tetrahedra of both the V4F4 and V4E6 type, which are constructed by a new building block based on a trinuclear zirconocene moiety and the dicarboxylate or tricarboxylate anions

Mesoporous Polyimide Thin Films as Dendrite-Suppressing Separators for Lithium–Metal Batteries

Lithium–metal batteries require the effective suppression of lithium dendrites to guarantee both high performance and safety. Today’s separators have macropores allowing lithium dendrites to traverse, leading to internal short circuits and other catastrophic results. Herein, we report a mesoporous polyimide separator for dendrite suppression. The polyimide separator exhibits mesopores of 21 nm width and a high storage modulus of 1.80 GPa. This mesoporous polyimide separator assists in the electrodeposition to form flat-top protrusions instead of sharp dendrites, therefore, allowing the safe cycling of lithium–metal batteries. This work is expected to advance the development of dendrite-suppressing strategies and contribute to the revival of lithium–metal batteries

Supplemental Material2 - Supplemental material for Propylene glycol alginate sodium sulphate attenuates LPS-induced acute lung injury in a mouse model

Supplemental material, Supplemental Material2 for Propylene glycol alginate sodium sulphate attenuates LPS-induced acute lung injury in a mouse model by Peng Zhao, Guoliang Liu, Yunfeng Cui and Xufang Sun in Innate Immunity</p

Using Scanning-Probe Block Copolymer Lithography and Electron Microscopy To Track Shape Evolution in Multimetallic Nanoclusters

Here we describe a general method for synthesizing multimetallic core–shell nanoclusters on surfaces. By patterning seeds at predesignated locations using scanning-probe block copolymer lithography, we can track shape evolution in nanoclusters and elucidate their growth pathways using electron microscopy. The growth of core–shell nanostructures on surface-bound seeds is a highly anisotropic process and often results in multimetallic anisotropic nanostructures. The shell grows at specific edge and corner sites of the patterned seeds and propagates predominately from the top hemisphere of the seeds