SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3649-0
Injectable hydrogels formed via dynamic chemical crosslinks hold great promise as drug delivery platforms due to their robust yet adaptable nature, stimuli-responsiveness, and tunable structures and properties. However, their inherently high water content poses a significant challenge for the efficient encapsulation and sustained release of hydrophobic drugs. Here, we present a novel injectable hydrogel system constructed via a strain-promoted disulfide-thiol exchange between dithiolane-functionalized polymer strands and thiolated core-shell nanoparticles (NPs) under physiological conditions. The hydrophobic core and hydrophilic shell structure of the NPs enables effective loading and protection of hydrophobic drugs, while rapid gelation occurs upon mixing the thiolated NPs with dithiolane-polymers in phosphate-buffered saline. The hydrogel shows excellent injectability, self-healing capability, in vitro biodegradability, and cytocompatibility. This hydrogel system enables sustained release of hydrophobic drugs over 32 days in aqueous media and supports sequential dual-drug release. Its redox-responsiveness under tumor-mimicking reducing conditions, enabled by the disulfide crosslinks, further facilitates controlled intracellular drug release. This multi-component platform offers a versatile strategy for designing advanced injectable hydrogels with potential applications in hydrophobic drug delivery and other biomedical fields.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3403-x
The adsorption of rare earth elements (REEs) from wastewater is vital for environmental protection and resource utilization. Adsorbents with magnetic properties are easy to separate but incorporating magnetic particles can reduce adsorption capacity by decreasing the surface area or blocking active sites. Herein, an efficient magnetic adsorbent (i.e., Fe3O4@PDAPEI), consisting of an Fe3O4 core, a polydopamine (PDA) intermediate layer and a polyethylenimine (PEI) outer layer, was designed to extract Gd3+, Nd3+, Ho3+, and Y3+ from low-concentration solutions with adsorption capacities of 168.3, 168.5, 179.7, and 180.3 mg/g, respectively. The adsorption capacities exceed those of most reported magnetic REE adsorbents in the literature. The adsorption behavior could be fitted to the pseudo-second-order model, intraparticle diffusion model, and Langmuir model. Fe3O4@PDAPEI exhibited good reusability, with the adsorption capacity remaining above 90% of the initial value after five reuse cycles. In addition, despite the presence of competing ions (i.e., Na+, Mg2+, and Al3+) in model wastewater, the adsorption capacity could be maintained above 100 mg/g for all four REEs. The adsorption mechanism was investigated via density functional theory calculations, zeta potential measurements, and surface force measurements via atomic force microscopy. REEs could adsorb on Fe3O4@PDAPEI through binding to primary amines and electrostatic interactions. This work presents a highly efficient magnetic adsorbent and evaluates the underlying interaction mechanism from both theoretical and experimental perspectives, shedding light on facile and efficient REE recovery in various engineering processes.