Exploring high‐efficiency reactive oxygen species (ROS)‐elimination materials is of great importance for combating oxidative stress in diverse diseases, especially stem‐cell‐based biotherapeutics. By mimicking the FeN active centers of natural catalase, here, an innovative concept to design ROS‐elimination artificial biocatalysts with Ru catalytic centers for stem‐cell protection is reported. The experimental studies and theoretical calculations have systematically disclosed the activity merits and structure diversities of different Ru sites when serving as ROS‐elimination artificial biocatalysts. Benefiting from the metallic electronic structures and synergetic effects of multiple sites, the artificial biocatalysts with Ru cluster centers present exceptional ROS‐elimination activity; notably, it shows much higher catalytic efficiency per Ru atom on decomposing H2O2 when compared to the isolated single‐atom Ru sites, which is more efficient than that of the natural antioxidants and recently reported state‐of‐the‐art ROS‐scavenging biocatalysts. The systematic stem‐cell protection studies reveal that the catalase‐like artificial biocatalysts can provide efficient rescue ability for survival, adhesion, and differentiation functions of human mesenchymal stem cells in high ROS level conditions. It is suggested that applying these artificial biocatalysts with Ru cluster centers will offer a new pathway for engineering high‐performance ROS‐scavenging materials in stem‐cell‐based therapeutics and many other ROS‐related diseases.
Exploring multifaceted and highly sensitive biosensors is a major challenge in biotechnology and medical diagnosis. Here, we create a new iridium (Ir) cluster-anchored metal−organic framework (MOF, namely, Ir NCs @Ti-MOF via a coordination-assisted strategy) as a peroxidase (POD)-mimetic nanoreactor for colorimetrically diagnosing hydrogen peroxide-related biomarkers. Owing to the Ir NCs −N/O coordination of Ti-MOF and unique enzymatic properties of Ir clusters, the Ir NCs @Ti-MOF exhibits exceptional and exclusive POD-mimetic activities (K m = 3.94 mM, V max = 1.70 μM s −1 , and turnover number = 39.64 × 10 −3 s −1 for H 2 O 2 ), thus demonstrating excellent POD-mimetic detecting activity and also super substrate selectivity, which is considerably more efficient than recently reported POD mimetics. Colorimetric studies disclose that this Ir NCs @Ti-MOF-based nanoreactor shows multifaceted and efficient diagnosing activities and substrate selectivity, such as a limit of detection (LOD): 14.12 μM for H 2 O 2 at a range of 0−900 μM, LOD: 3.41 μM for L-cysteine at a range of 0−50 μM, and LOD: 20.0 μM for glucose at a range of 0− 600 μM, which enables an ultrasensitive and visual determination of abundant H 2 O 2 -related biomarkers. The proposed design will not only provide highly sensitive and cheap colorimetric biosensors in medical resource-limited areas but also offer a new path to engineering customizable enzyme-mimetic nanoreactors as a powerful tool for accurate and rapid diagnosis.
Exploration of efficient antioxidase-like reactive oxygen nanobiocatalysts (ROBCs) is a major challenge in combating oxidative stress-related diseases. Herein, the molecularly well-defined Ru-porphyrin-networks (Ru-Por-Net)-based ROBCs with ultrafast and reversible redox-centers for catalytic elimination of reactive oxygen species (ROS) are reported. Owing to the large π-conjugated networks, Ru-N coordination structures, and unique electronic and redox properties of atomic Ru sites, the Ru-Por-Net-based ROBCs exhibit exceptional catalytic ROS-scavenging activities. It is considerably more efficient than recently reported state-of-the-art anti-ROS biocatalysts. Notably, a new nucleophilic attack pathway to eliminate H 2 O 2 and produce O 2 is proposed via theoretical calculations, and the desorption of the OO* process is identified as the rate-determining step of atomic Ru centers. Cellular studies reveal that the new ROBCs can efficiently secure the survival, adhesion, spreading, and differentiation of the stem cells in high-ROS-level microenvironments. In vivo rat periodontitis treatments further demonstrate their superior anti-ROS therapeutic effects. This study provides significant insights into the crucial functions of Ru-N coordinated porphyrin-networks in catalytic ROS-scavenging and offers a new strategy to engineer high-performance antioxidase-like nanobiocatalysts for stem cell-based therapies and inflammatory diseases.
Generally, surface initiated-atom transfer radical polymerization (SI-ATRP) often suffers from the immobilization of the initiator on the surface-inert substrate. Develop an effective and versatile one-step method to anchor priming sites...
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