As an excellent hosting matrices for enzyme immobilization, metal-organic framework (MOFs) provides superior physical and chemical protection for biocatalytic reactions. In recent years, the hierarchical porous metal-organic frameworks (HP-MOFs) have shown great potential in enzyme immobilization due to their flexible structural advantages. To date, a variety of HP-MOFs with intrinsic or defective porous have been developed for the immobilization of enzymes. The catalytic activity, stability and reusability of enzyme@HP-MOFs composites are significantly enhanced. This review systematically summarized the strategies for developing enzyme@HP-MOFs composites. In addition, the latest applications of enzyme@HP-MOFs composites in catalytic synthesis, biosensing and biomedicine were described. Moreover, the challenges and opportunities in this field were discussed and envisioned.
Metal-Organic Frameworks/chemistry* ; Porosity ; Enzymes, Immobilized/chemistry* ; Biocatalysis ; Catalysis

OBJECTIVE: To review antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants, so as to provide reference for subsequent research. METHODS: The related research literature on antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants in recent years was reviewed, and the research progress was summarized based on different kinds of antibacterial substances and osteogenic active substances. RESULTS: At present, the antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants includes: ① Combined coating strategy of antibiotics and osteogenic active substances. It is characterized in that antibiotics can be directly released around titanium-based implants, which can improve the bioavailability of drugs and reduce systemic toxicity. ② Combined coating strategy of antimicrobial peptides and osteogenic active substances. The antibacterial peptides have a wide antibacterial spectrum, and bacteria are not easy to produce drug resistance to them. ③ Combined coating strategy of inorganic antibacterial agent and osteogenic active substances. Metal ions or metal nanoparticles antibacterial agents have broad-spectrum antibacterial properties and various antibacterial mechanisms, but their high-dose application usually has cytotoxicity, so they are often combined with substances that osteogenic activity to reduce or eliminate cytotoxicity. In addition, inorganic coatings such as silicon nitride, calcium silicate, and graphene also have good antibacterial and osteogenic properties. ④ Combined coating strategy of metal organic frameworks/osteogenic active substances. The high specific surface area and porosity of metal organic frameworks can effectively package and transport antibacterial substances and bioactive molecules. ⑤ Combined coating strategy of organic substances/osteogenic active substancecs. Quaternary ammonium compounds, polyethylene glycol, N-haloamine, and other organic compounds have good antibacterial properties, and are often combined with hydroxyapatite and other substances that osteogenic activity. CONCLUSION The factors that affect the antibacterial and osteogenesis properties of titanium-based implants mainly include the structure and types of antibacterial substances, the structure and types of osteogenesis substances, and the coating process. At present, there is a lack of clinical verification of various strategies for antibacterial/osteogenesis dual-functional surface modification of titanium-based implants. The optimal combination, ratio, dose-effect mechanism, and corresponding coating preparation process of antibacterial substances and bone-active substances are needed to be constantly studied and improved.
Anti-Bacterial Agents/pharmacology* ; Coated Materials, Biocompatible/chemistry* ; Metal-Organic Frameworks/pharmacology* ; Osteogenesis ; Surface Properties ; Titanium/pharmacology* ; Prostheses and Implants

A magnetic metal organic framework (MMOF) was synthesized and used to separate Sr2+ in aqueous solution. The shape and structure of prepared Fe3O4@UiO-66-NH2 were characterized, and the absorbed concentration of strontium was determined through inductively coupled plasma mass spectrometry. The results indicated that Fe3O4 and UiO-66-NH2 combined through chemical bonding. The experimental adsorption results for separation of Sr2+ in aqueous solution indicated that the adsorption of Sr2+ to Fe3O4@UiO-66-NH2 increased drastically from pH 11 to pH 13. The adsorption isotherm model indicated that the adsorption of Sr2+ conformed to the Freundlich isotherm model (R2 = 0.9919). The MMOF thus inherited the superior qualities of magnetic composites and metal organic frameworks, and can easily be separated under an external magnetic field. This MMOF thus has potential applications as a magnetic adsorbent for low level radionuclide 90Sr.
Adsorption ; Ferrosoferric Oxide ; chemistry ; Hydrogen-Ion Concentration ; Metal-Organic Frameworks ; chemical synthesis ; chemistry ; Models, Theoretical ; Nanoparticles ; chemistry ; Strontium ; analysis ; Surface Properties ; Water Pollutants, Radioactive ; analysis ; Water Purification ; methods