We have fabricated a mixed-shell polymeric micelle (MSPM) that closely mimics the natural molecular chaperone GroEL-GroES complex in terms of structure and functionality. This MSPM, which possesses a shared PLA core and a homogeneously mixed PEG and PNIAPM shell, is constructed through the co-assembly of block copolymers poly(lactide-b-poly(ethylene oxide) (PLA-b-PEG) and poly(lactide)-b-poly(N-isopropylacryamide) (PLA-b-PNIPAM). Above the lower critical solution temperature (LCST) of PNIPAM, the MSPM evolves into a core-shell-corona micelle (CSCM), as a functional state with hydrophobic PNIPAM domains on its surface. Light scattering (LS), TEM, and fluorescence and circular dichroism (CD) spectroscopy were performed to investigate the working mechanism of the chaperone-like behavior of this system. Unfolded protein intermediates are captured by the hydrophobic PNIPAM domains of the CSCM, which prevent harmful protein aggregation. During cooling, PNIPAM reverts into its hydrophilic state, thereby inducing the release of the bound unfolded proteins. The refolding process of the released proteins is spontaneously accomplished by the presence of PEG in the mixed shell. Carbonic anhydrase B (CAB) was chosen as a model to investigate the refolding efficiency of the released proteins. In the presence of MSPM, almost 93 % CAB activity was recovered during cooling after complete denaturation at 70 °C. Further results reveal that this MSPM also works with a wide spectrum of proteins with more-complicated structures, including some multimeric proteins. Given the convenience and generality in preventing the thermal aggregation of proteins, this MSPM-based chaperone might be useful for preventing the toxic aggregation of misfolded proteins in some diseases.

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A polyamide-66 ionised with 6.5 mol% of CaCl2, an optimum heterogeneous nucleator, maximally expedites poly(ethylene terephthalate) crystallisation by medium-concentration ion–dipole interactions.

At high temperature, many enzymes are inactivated by aggregations at hydrophobic sites which are exposed on denaturation. Isolating denatured enzymes via hydrophobic interactions with other material is a significant method to prevent enzymes from aggregation. But the temperature-sensitive polymer poly(N-isopropylacrylamide) (PNIPAAm), supposed to protect enzymes spontaneously at high temperatures, can not efficiently complex denatured carbonic anhydrase B (CAB, as a model enzyme) in bulk aqueous solution due to different phase transition speeds. Here, we present a novel method for protecting enzymes against heat inactivation, in which PNIPAAm and CAB are encapsulated in a confined space constructed by reverse microemulsion. At high temperatures, PNIPAAm forms nanoscale aggregates possessing both large specific surface areas and hydrophobic surfaces, and then adsorbs denatured CAB via hydrophobic interactions to avoid intermolecular aggregation of CAB. With cooling, CAB is released spontaneously and recovers its activity. The assays for enzymatic activity demonstrate that CAB is effectively protected against heat inactivation through this method (protection efficiency is up to 83.2%).

The comb‐like styrene‐maleic anhydride copolymer‐g‐isatoic anhydride‐methoxypolyethylene glycols condensate (SMA‐g‐IA‐MPEG) was synthesized by transesterification and amidation reaction. The chemical structure of SMA‐g‐IA‐MPEG was characterized by FTIR and 1H‐NMR. The comb‐like modified SMA was first employed as the dispersant of disperse dyes suspension in this paper. The addition of SMA‐g‐IA‐MPEG dispersant improved the dispersibility and stability of the disperse dyes suspension observably due to the steric hindrance and electrostatic repulsion on the surface of dye particles. The impacts of the length of side chains on the particle size, Zeta potential, centrifugal stability, and temperature sensitivity of disperse dyes suspensions were particularly discussed. The results showed that SMA‐g‐IA‐MPEG with moderate length of side chain had the best dispersibility for disperse dyes suspension and the average particle size of dyes can be reduced to 356.1 nm. Thus, the comb‐like dispersants played a vital role in dispersing of disperse dyes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47330.

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