Robust biomacromolecules could be used for a wide range of biotechnological applications. Here the authors report a biomimetic mineralization process, in which biomolecules are encapsulated within metal-organic frameworks, and their stability is subsequently increased without significant bioactivity loss.

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Biomimetic mineralization of metal-organic frameworks as protective coatings for biomacromolecules.

This work reports a facile approach to fabricate an artificial enzyme system for tandem catalysis. NiPd hollow nanoparticles and glucose oxidase (GOx) were simultaneously immobilized on ZIF-8 via a co-precipitation method. The as-prepared GOx@ZIF-8(NiPd) nanoflower not only exhibited the peroxidase-like activity of NiPd hollow nanoparticles but also maintained the enzymatic activity of GOx. A colorimetric sensor for rapid detection of glucose was fabricated through the GOx@ZIF-8(NiPd) based multi-enzyme system and the cascade reaction for the visual detection of glucose was successfully combined into one step. Moreover, the GOx@ZIF-8(NiPd) modified electrode showed good bioactivity of GOx and high electrocatalytic activity for the oxygen reduction reaction (ORR), which could also be used for electrochemical detection of glucose. The proposed strategy for the fabrication of artificial multi-enzyme system builds a potential bridge of cooperation between nanozyme and natural enzyme.

GOx@ZIF-8(NiPd) Nanoflower: An Artificial Enzyme System for Tandem Catalysis.

Crystallization inhibition in solid dispersions of MK‐0591 and poly(vinylpyrrolidone) polymers

Ionomers are polymers with bonded ionic species that are used under conditions where the salt groups are in a condensed state. This Feature Article discusses the state of our understanding of ionomers and the historical applications of these nanostructured polymers. It also discusses modern methods for synthesizing new ionomers and describes a number of relatively new applications for ionomers and the potential use of these materials in contemporary technologies, including, shape memory and self-healing materials and supramolecular polymer systems.

Perspective: Ionomer Research and Applications

The dewetting of low molecular weight sulfonated polystyrene ionomers (SPS) on inorganic silicon oxide substrates is compared with unmodified polystyrene (PS, Mw ) 4000) using a combination of X-ray reflectivity, optical and atomic force microscopy. The amounts of sulfonate group and metal counterion (Li + ,Z n 2+ ) were both varied in our study. Unlike unmodified PS, which readily dewets the substrate, a strong inhibition of dewetting occurs for low sulfonation (=2.3 mol %), and no apparent dewetting was found for high sulfonation (g7 mol %). For ZnSPS, dewetting was not observed in any of the films, even for those with very low sulfonation. Comparison with bulk rheological data suggests that inter- and intramolecular ionomer complexation may be important in retarding the dewetting process (a nonequilibrium effect), in addition to an increased wettability arising from long-range electrostatic polymer-surface interactions.

Control of Polystyrene Film Dewetting through Sulfonation and Metal Complexation

Electron paramagnetic resonance (EPR), Fourier transform infrared (FTIR), and solid-state 15N nuclear magnetic resonance (15N-NMR) spectroscopies were used to characterize the structure and relative strength of the interactions between metal sulfonate and amide groups in blends of lightly sulfonated polystyrene ionomers and an N-methylated polyamide, poly(N,N‘-dimethylethylene sebacamide), and low molecular weight model complexes. The metal sulfonate groups, which aggregate in the neat ionomer, were dispersed by the polyamide in the blend as a consequence of a complexation that involved the sulfonate cation and both the carbonyl oxygen and the amide nitrogen of the polyamide. The FTIR and 15N-NMR spectra were consistent with a 2pz electron redistribution model for the complex, in which electrons migrate from the nitrogen to the metal ion through the carbonyl group. The sulfonate anion did not appear to particpate in the complex, but it remained in the vicinity of the metal cation. The strength of the ion−...

Yi Feng

Papers

Compatibilization of polymer blends by complexation. 1. Spectroscopic characterization of ion-amide interactions in ionomer/polyamide blends