Ca^(2+)-supplying black phosphorus-based scaffolds fabricated with microfluidic technology for osteogenesis

Effective osteogenesis remains a challenge in the treatment of bone defects.The emergence of artificial bone scaffolds provides an attractive solution.In this work,a new biomineralization strategy is proposed to facilitate osteogenesis through sustaining supply of nutrients including phosphorus(P),calcium(Ca),and silicon(Si).We developed black phosphorus(BP)-based,three-dimensional nanocomposite fibrous scaffolds via microfluidic technology to provide a wealth of essential ions for bone defect treatment.The fibrous scaffolds were fabricated from 3D poly(L-lactic acid)(PLLA)nanofibers(3D NFs),BP nanosheets,and hydroxyapatite(HA)-porous SiO2 nanoparticles.The 3D BP@HA NFs possess three advantages:i)stably connected pores allow the easy entrance of bone marrow-derived mesenchymal stem cells(BMSCs)into the interior of the 3D fibrous scaffolds for bone repair and osteogenesis;ii)plentiful nutrients in the NFs strongly improve osteogenic differentiation in the bone repair area;iii)the photothermal effect of fibrous scaffolds promotes the release of elements necessary for bone formation,thus achieving accelerated osteogenesis.Both in vitro and in vivo results demonstrated that the 3D BP@HA NFs,with the assistance of NIR laser,exhibited good performance in promoting bone regeneration.Furthermore,microfluidic technology makes it possible to obtain high-quality 3D BP@HA NFs with low costs,rapid processing,high throughput and mass production,greatly improving the prospects for clinical application.This is also the first BP-based bone scaffold platform that can self-supply Ca^(2+),which may be the blessedness for older patients with bone defects or patients with damaged bones as a result of calcium loss.

An NIR photothermal-responsive hybrid hydrogel for enhanced wound healing

Moderately regulating vascularization and immune microenvironment of wound site is necessary to achieve scarless wound healing of the skin.Herein,we have prepared an angiogenesis-promoting and scar-preventing band-aid with a core-shell structure,that consists of MXene-loaded nanofibers(MNFs)as the core and dopamine-hyaluronic acid hydrogel(H)as the shell(MNFs@V-H@DA)to encapsulate a growth factor(vascular endothelial growth factor,VEGF,abbreviated as V)and H2S donor(diallyl trisulfide,DATS,abbreviated as DA).The continuous release of DA from this system produced H2S,which would successfully induce macrophages to polarize into M2-lile phenotype,regulating the immune microenvironment and inhibiting an excessive inflammatory response at the wound sites.It is conducive to the proliferation of skin cells,facilitating the wound healing.In addition,an appropriate amount of VEGF can be released from the MXene nanofibrous skeleton by adjusting the time of near-infrared(NIR)light exposure,preventing excessive neovascularization and extracellular matrix deposition at the wound sites.Collectively,this NIR photothermal-responsive band-aid achieved scarless wound healing through gradient-controlled vascularization and a related immune sequential reaction of damaged skin tissue.