Ultrasound augmenting injectable chemotaxis hydrogel for articular cartilage repair in osteoarthritis

The increasing incidence of osteoarthritis(OA) seriously affects life quality,posing a huge socioeco nomic burden.Tissue engineering technology has become a hot topic in articular cartilage repair as one of the key treatment methods to alleviate OA.Hydrogel,one of the most commonly used scaffold materials,ca n provide a good extracellular matrix microenvironment fo r seed cells such as bone marrow mesenchymal stem cells(BMSCs),which can promote cartilage regeneration.However,the low homing rate of stem cells severely limits their role in promoting articular cartilage regeneration.Stro mal cell-derived factor-1α(SDF-1α) plays a crucial role in the activatio n,mobilization,homing,and migration of MSCs.He rein,a novel injectable chemotaxis hydrogel,composed of chitosan-based injectable hydrogel and embedding SDF-1α-loaded nanodroplets(PFP@NDs-PEG-SDF-1α) was designed and fabricated.The ultrasound was then used to augment the injectable chemotaxis hydrogel and promote the homing migration of BMSCs for OA cartilage repair.The effect of ultrasound augmenting injectable PFP@NDs-PEG-SDF-1α/hydrogel on the migration of BMSCs was verified in vitro and in vivo,which re markably promotes stem cell homing and the repair of cartilage in the OA model.Therefore,the treatment strategy of ultrasound augmenting injectable chemotaxis hydrogel has a bright potential for OA articular cartilage repair.

Ti-MOF-based biosafety materials for efficient and long-life disinfection via synergistic photodynamic and photothermal effects

Pathogenic bacterial infection is severely threatening public health globally.The multi-modal antibacterial nanoplatforms could significantly improve the antibacterial efficiency.Here,we report a metal(Ti)-organic framework(MOF)derived nanocarbon(C-Ti-MOF)as a biosafety material for synergistic sterilization of pathogenic bacteria via efficient photodynamic catalysis and robust photothermal effects.The C-Ti-MOF consists of abundant TiO_(2) nanodots embedded in graphitic carbon frameworks.Under visible light irradiation,TiO_(2) nanodots can catalyze H_(2)O_(2) and O_(2) to produce superoxide anion(•O_(2)^(–))and singlet oxygen(1O2),respectively.Meanwhile,under near-infrared irradiation(NIR),C-Ti-MOF can generate massive heat to destroy bacterial membranes.Systematic antibacterial experiments reveal that the C-Ti-MOF nanoagents have a long-lasting and nearly 100%bactericidal ratio at an extremely low dose(0.16 mg/mL),which is much better than the state-of-the-art TiO_(2)(Commercial TiO_(2)(P25),0.64 mg/mL).Furthermore,the C-Ti-MOF can be electrospun into an antibacterial nanofiber membrane via mixing with polymeric matrix for treating bacteriacontaminated wastewater,and the membranes possess integrated antibacterial activity and excellent biocompatibility.Our study demonstrates a promising Ti-MOF-based biosafety material for efficient and long-life disinfection,which may stimulate new research in MOF-related biological applications in various disciplines ranging from water decontaminations to nanotherapeutics.

Nanostructures and catalytic atoms engineering of tellurium-based materials and their roles in electrochemical energy conversion

With the dramatic developments of renewable and environmental-friendly electrochemical energy conversion systems,there is an urgent need to fabricate durable and efficient electrocatalysts to address the limitation of high overpotentials exceeding thermodynamic requirements to facilitate practical applications.Recently,tellurium-based nanomaterials(Te NMs)with unique chemical,electronic,and topological properties,including Te-derived nanostructures and transition metal tellurides(TMTs),have emerged as one of the most promising electrocatalytic materials.In the absence of comprehensive and guiding reviews,this review comprehensively summarizes the main advances in designing emerging Te NMs for electrocatalysis.First,the engineering strategies and principles of Te NMs to enhance their electrocatalytic activity and stability from the nanostructures to the catalytic atoms are discussed in detail,especially on the chemical/physical/multiplex templating strategies,heteroatom doping,vacancy/defect engineering,phase engineering,and the corresponding mechanisms and structure-performance correlations.Then,typical applications of Te NMs in electrocatalysis are also discussed in detail.Finally,the existing key issues and main challenges of Te NMs for electrocatalysis are highlighted,and the development trend of Te NMs as electrocatalysts is expounded.This review provides new concepts to guide future directions for developing Te NMs-based electrocatalysts,thereby promoting their future wide applications in electrochemical energy systems.