Deep tumor penetration, long blood circulation, rapid drug release, and sufficient stability are the most concerning dilemmas of nano-drug-delivery systems for efficient chemotherapy. Herein, we develop reduction/oxidation-responsive hierarchical nanoparticles co-encapsulating paclitaxel (PTX) and pH-stimulated hyaluronidase (pSH) to surmount the sequential biological barriers for precise cancer therapy. Poly­(ethylene glycol) diamine (PEG-dia) is applied to collaboratively cross-link the shell of nanoparticles self-assembled by a hyaluronic acid–stearic acid conjugate linked via a disulfide bond (HA–SS–SA, HSS) to fabricate the hierarchical nanoparticles (PHSS). The PTX and pSH coloaded hierarchical nanoparticles (PTX/pSH-PHSS) enhance the stability in normal physiological conditions and accelerate drug release at tumorous pH, and highly reductive or oxidative environments. Functionalized with PEG and HA, the hierarchical nanoparticles preferentially prolong the circulation time, accumulate at the tumor site, and enter MDA-MB-231 cells via CD44-mediated endocytosis. Within the acidic tumor micro-environment, pSH would be partially reactivated to decompose the dense tumor extracellular matrix for deep tumor penetration. Interestingly, PTX/pSH-PHSS could be degraded apace by the completely activated pSH within endo/lysosomes and the intracellular redox micro-environment to facilitate drug release to produce the highest tumor inhibition (93.71%) in breast cancer models.

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Excellent mechanical properties are indispensable for the wide application of supercapacitors and various wearable devices. In this article, a novel double‐crosslinked hydrogel electrolyte (DC‐GPE) is prepared by the combination of the hydrophobic association of acrylamide with the amphiphilic monomer AEO‐9‐AC and the ionic complexation of acrylic acid with Fe3+ for the first time by a two‐step method. Owing to the dual energy dissipation network, the DC‐GPE exhibits an excellent tensile strength of up to 3.1 MPa, an elongation at break of more than 900 % and a toughness of 18.1 MJ m−3, which is far beyond the currently reported hydrogel electrolyte. Moreover, the ionic conductivity of the DC‐GPE achieves as high as 40.1 mS cm−1, which is 3 times higher than the corresponding LiClO4 solution electrolyte (12.3 mS cm−1). Besides, the activated carbon‐based supercapacitor assembled by the DC‐GPE shows excellent electrochemical performance, which is superior to most activated carbon‐based supercapacitors. These results demonstrate that the DC‐GPE shows a great application prospect in wearable devices like supercapacitors. Significantly, the new dual physical cross‐linking strategy improves the contradiction between the strength and the toughness of the gel electrolyte materials. And provides a new solution for preparing high‐strength as well as high‐toughness gel electrolyte.

Poly(ethylene glycol) diglycidyl ether‐furfurylamine (PGFA) containing pendant furan was synthesized, and a series of crosslinked materials with thermally reversible capacity were synthesized through a furan/maleimide Diels–Alder (DA) reaction between PGFA and bismaleimide (BMI). The kinetics of the PGFA/BMI DA reaction were studied by Fourier transform infrared spectroscopy (FTIR). The reaction conversion rate, the reaction rate constant, and the energy of the DA reaction at different temperatures were calculated. In addition, the retro Diels–Alder (rDA) reaction was studied via 1H‐NMR, differential scanning calorimetry, and in situ FTIR. The occurrence of the retro DA reaction has been characterized clearly. Finally, the mechanical properties of the materials were obtained by dynamic mechanical and tensile tests. The storage modulus decreased obviously when the temperature reached over 90 °C, which proved that the materials were thermally reversible at high temperature. By changing the proportion of the crosslinking agent BMI, the best‐performing materials were obtained, and the properties of the materials were basically unchanged after recycling. Thus we have obtained an excellent reusable material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47352.

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