SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3696-3
The development of substitutable meniscus implants that can effectively protect articular cartilage remains a great challenge. Herein, a polyurethane with chemical crosslinking and sulfobetaine extenders containing hydrophobic chains (PU-CL-hSB) is developed, which could improve comprehensive properties and long-term stability simultaneously. By regulating the mole ratio of functional groups, PU-CL-hSB with appropriate mechanical properties, excellent tribological properties, and good fatigue resistance is used to prepare substitutable meniscus implant by hot-pressing. Due to the synergistic effect of functional groups, PU-CL-hSB meniscus implant presents comparable or even superior properties to native meniscus. It withstands a maximum force of 26.08 N versus 25.14 N for native meniscus, an energy dissipation from 45.93 to 39.17 N mm compared to 28.83 to 19.11 N mm for native meniscus over 300 cycles, and a friction coefficient from 0.08 to 0.19 compared to 0.11 to 0.26 for native meniscus. This PU-CL-hSB meniscus implant is further implanted into live rabbit knee joints for 8 and 25 weeks by a new approach, and in vivo data indicate that PU-CL-hSB meniscus implant not only protects articular cartilage from severe damage without eliciting inflammatory responses, but also can maintain normal physiological activities in the native state. Our findings present a substitutable meniscus implant that could be applied in vivo and propose evaluation methodologies for meniscus implants.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025022302
The escalating environmental contamination by mercury ions (Hg2+) poses severe risks to ecosystems and human health, necessitating the development of rapid, sensitive, and cost-effective detection methods. In this study, Fe1-xS@CNT composite nanozymes were synthesized via a straightforward solvothermal approach. The nanozymes exhibit uniform morphology, structural stability, and significant peroxidase (POD)-like activity. The incorporation of carbon nanotubes (CNT) facilitates electron transfer, enhancing the Fenton reaction between Fe2+/Fe3+ to generate abundant reactive oxygen species (ROS), primarily hydroxyl radicals (·OH) and superoxide anions (·O2−). The synergistic action of these ROS and photogenerated holes (h+) promotes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to a blue-colored product (oxTMB), establishing a colorimetric system of Fe1-xS@CNT + H2O2 + TMB. The specific binding of S2− on the nanozyme surface to Hg2+ inhibits POD activity, reducing the absorbance of the system. This principle was harnessed to develop a colorimetric method for Hg2+ quantification in environmental water samples. The method demonstrates a linear range of 0.1–500 μg·L−1 and a limit of detection (LOD) of 0.04 μg·L−1. Validation in real water samples (campus and tap water) showed recoveries between 94.4% and 111.1% with relative standard deviations (RSD) below 3.0%, comparable to atomic fluorescence spectrometry. The method offers advantages of simplicity, rapid analysis, and naked-eye visibility, providing a novel approach for on-site monitoring of heavy metal pollutants.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3864-4
Organic room temperature phosphorescence (RTP) materials, particularly those emitting in the near-infrared (NIR) region, hold great promise for bioimaging due to their deep-tissue penetration and minimal autofluorescence interference. However, achieving efficient NIR RTP with long lifetimes remains challenging due to inefficient triplet exciton utilization. Herein, we propose a dark triplet state activation strategy to achieve efficient NIR RTP by leveraging host–guest energy transfer. Using benzophenone derivatives (BP, OBP, MBP, PBP) as rigid host matrices with high intersystem crossing (ISC) efficiency and an NIR fluorophore (MPTCF) as the guest, we achieve efficient Dexter-type triplet-triplet energy transfer (TTET) that converts non-emissive host triplets into guest-centered NIR phosphorescence. Systematic optimization of the host–guest system has shown that PBP/MPTCF exhibits exceptional performance, including long phosphorescence centered at 705 nm, an ultralong phosphorescence lifetime (210.3 ms), and high ISC efficiency (44.4%). When fabricated into nanoparticles (NPs), PBP/MPTCF exhibits superior performance, featuring prolonged phosphorescence signals (>120 s), deep tissue penetration capability (>2 mm), and excellent biocompatibility (cell viability >95% at 300 μM). In addition, this system enables high-contrast subcutaneous imaging with excellent dispersibility and stable in vivo imaging capability. More importantly, PBP/MPTCF NPs demonstrate precise lymph node mapping through time-gated phosphorescence imaging and efficient tumor visualization within 4 h post-injection with a high tumor-to-liver ratio of 2.8. The successful activation of dark triplet states through this host–guest approach provides a general design principle for developing high-performance NIR RTP materials, while the demonstrated biomedical applications highlight their significant potential for advanced bioimaging and precision diagnostics.