Improving hole transfer of boron nitride quantum dots modified PDI for efficient photodegradation

In recent years,organic photocatalyst under visible-light absorption has shown significant potential for solving environmental problems.However,it is still a great challenge for constructing a highly active organic photocatalyst due to the low separation efficiency of photogenerated carriers.Herein,an effective and robust photocatalyst perylene-3,4,9,10-tetracarboxylic diamide/boron nitride quantum dots(PDI/BNQDs),consisting of selfassemble PDI withπ–πstacking structure and BNQDs,has been constructed and researched under visible light irradiation.The PDI/BNQDs composite gradually increases organic pollutant photodegradation with the loading amount of BNQDs.With 10 mL of BNQDs solution added(PDI/BNQDs-10),the organic pollutant photodegradation performance reaches a maximum,about 6.16 times higher with methylene blue and 1.68 times higher with ciprofloxacin than that of pure PDI supramolecular.The enhancement is attributed to improved separation of photogenerated carriers from self-assembled PDI by BNQDs due to their preeminent ability to extract holes.This work is significant for the supplement of PDI supramolecular composite materials.We believe that this photocatalytic design is capable of expanding organic semiconductors’potential for their applications in photocatalysis.

Doping bioactive elements into a collagen scaffold based on synchronous self-assembly/mineralization for bone tissue engineering

Pure collagen is biocompatible but lacks inherent osteoinductive,osteoimmunomodulatory and antibacterial activities.To obtain collagen with these characteristics,we developed a novel methodology of doping bioactive elements into collagen through the synchronous self-assembly/mineralization(SSM)of collagen.In the SSM model,amorphous mineral nanoparticles(AMN)(amorphous SrCO3,amorphous Ag3PO4,etc.)stabilized by the polyampholyte,carboxymethyl chitosan(CMC),and collagen molecules were the primary components under acidic conditions.As the pH gradually increased,intrafibrillar mineralization occurred via the self-adaptive interaction between the AMNs and the collagen microfibrils,which were self-assembling;the AMNs wrapped around the microfibrils became situated in the gap zones of collagen and finally transformed into crystals.Srdoped collagen scaffolds(Sr-CS)promoted in vitro cell proliferation and osteogenic differentiation of rat bone marrow mesenchymal stromal cells(rBMSCs)and synergistically improved osteogenesis of rBMSCs by altering the macrophage response.Ag-doped collagen scaffolds(Ag-CS)exhibited in vitro antibacterial effects on S.aureus,as well as cell/tissue compatibility.Moreover,Sr-CS implanted into the calvarial defect of a rat resulted in improved bone regeneration.Therefore,the SSM model is a de novo synthetic strategy for doping bioactive elements into collagen,and can be used to fabricate multifunctional collagen scaffolds to meet the clinical challenges of encouraging osteogenesis,boosting the immune response and fighting severe infection in bone defects.