Here, we constructed a nanostructured pH/redox dual-responsive supramolecular drug carrier with both aggregation-induced emission (AIE) and Forster resonance energy transfer (FRET) effects, which enabled selective drug release and monitoring drug delivery and release processes. Taking the hyperbranched polyamide amine (H-PAMAM) with intrinsic AIE effects as the core, poly­(ethylene glycol) (PEG) was bridged on its periphery by dithiodipropionic acid. Then, through the host–guest interaction of PEG and α-cyclodextrin, the supramolecular nanoparticles with AIE effects were constructed to load the anticancer drug doxorubicin (DOX). The supramolecular assembly has sufficiently large DOX loading due to the abundant cavities formed by branched structures. The hyperbranched core H-PAMAM has strong fluorescence, and the dynamic track of drug carriers and the dynamic drug release process can be monitored by the AIE and FRET effects between H-PAMAM and DOX, respectively. Furthermore, the introduction of disulfide bonds and the pH sensitivity of H-PAMAM enable the achievement of rapid selective release of loaded DOX at the tumor while remaining stable under normal physiological conditions. In vitro cytotoxicity indicates that the drug-loaded supramolecular assembly has a good therapeutic effect on cancer. In addition, the H-PAMAM core is different from the traditional AIE functional group, which has no conjugated structure, such as a benzene ring, thereby providing better biocompatibility. This technology will have broad applications as a new drug delivery system.

In this work, the biodegradable and histocompatibility properties of pure Mg and ZK60 alloy were investigated as new temporary implants for urinary applications. The corrosion mechanism in artificial urine was proposed using electrochemical impedance spectroscopy and potentiodynamic polarization tests. The corrosion potential of pure magnesium and ZK60 alloy were −1820 and −1561 mV, respectively, and the corrosion current densities were 59.66 ± 6.41 and 41.94 ± 0.53 μA cm−2, respectively. The in vitro degradation rates for pure Mg and ZK60 alloy in artificial urine were 0.382 and 1.023 mm/y, respectively, determined from immersion tests. The ZK60 alloy degraded faster than the pure Mg in both artificial urine and in rat bladders (the implants of both samples are ø 3 mm × 5 mm). Histocompatibility evaluations showed good histocompatibility for the pure Mg and ZK60 alloy during the 3 weeks post-implantation in rat bladders, and no harm was observed in the bladder, liver and kidney tissues. The results provide key information on the degradation properties and corrosion mechanism of pure Mg and ZK60 alloy in the urinary system.

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The Fe/Zr composite coating was prepared by duplex Fe/Zr ion implantation and deposition to modify the microstructure and corrosion behavior of Mg-5.5 Zn-0.6 Zr (in wt.%, ZK60) alloy. The surface and interface characteristics were investigated using X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM). The results showed that the Fe/Zr composite coating exhibited a bi-layer microstructure of outer Fe-rich layer and inner Zr-rich layer. Multi-phases of α-Fe, ZrO0.35 and Zr6Fe3O were formed on the modified surface. The electrochemical measurements and immersion tests revealed an improvement of corrosion behavior for the surface-modified sample due to the protective effect of Fe/Zr composite coating.

Biocompatible Janus composite membrane with double self‐repairing ability is constructed on the surface of magnesium, using paeonol‐doped poly(ε‐caprolactone) (P@PCL) as a hydrophobic layer and imide‐bond‐based chitosan hydrogel (PGD) as a hydrophilic layer. A copper mesh is used as the base to indirectly study this specific ability of the as‐prepared Janus membrane. The water contact angle of the Janus copper mesh‐P@PCL‐PGD with the hydrophobic layer at the bottom and the hydrophilic layer at the top is 65°, and its water retention height reached 5.1 cm, showing the strongest prevention capacity of water infiltration. Further, the damage of the hydrophobic layer is repaired by the corrosion inhibitor and the magnesium ion complex membrane; the hydrophilic layer is healed by the quick response of the imine bond in the gel to the pH change. Among all samples, the weight loss rate of Mg‐P@PCL‐PGD is found to be the smallest—only 1.19% after 12 d and 5.20% after 21 d. In short, effective protection of magnesium is achieved which is conducive to cell adhesion and proliferation, through systematically summarizing the synergy between Janus membrane and dual self‐repair. The related results are distinctive and will open up new research directions for corrosion protection of metals.

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