We demonstrated one-step method to fabricate two different sizes of graphene quantum dots (GQDs) through chemical cutting from graphene oxide (GO), which had many advantages in terms of simple process, low cost, and large scale in manufacturing with higher production yield comparing to the reported methods. Several analytical methods were employed to characterize the composition and morphology of the resultants. Bright blue luminescent GQDs were obtained with a produced yield as high as 34.8%. Moreover, how the different sizes affect fluorescence wavelength mechanism was investigated in details.

We report the preparation, luminescent properties, and bioimaging applications of a novel zinc sulfide (core)-two-photon dye−silica (shell) multilayered heterostructure. The method utilizes reverse micelles synthesis involving multistep reactions as a result of which composite nanoparticles having different sizes and morphology can be obtained. The size of these composite nanoparticles is typically 15−30 nm. An increase in the luminescence intensity (∼70 times higher) and in fluorescence lifetime is observed for the dye encapsulated within the silica nanobubble. Photobleaching results indicate that the dye is truly encapsulated and the silica shell provides a barrier to penetration of oxygen, thereby making the dye more photostable. The application of these particles as nanoprobes for bioimaging of cells using two-photon laser scanning microscopy is also presented.

Polyetheretherketone (PEEK) is a biocompatible polymer, but its clinical application is largely limited due to its inert surface. To solve this problem, a multifunctional PEEK implant is urgently fabricated. In this work, a dual-metal−organic framework (Zn−Mg-MOF74) coating is bonded to PEEK using a mussel-inspired polydopamine interlayer to prepare the coating, and then, dexamethasone (DEX) is loaded on the coating surface. The PEEK surface with the multifunctional coating provides superior hydrophilicity and favorable stability and forms an alkaline microenvironment when Mg 2+ , Zn 2+ , 2,5-dihydroxyterephthalic acid, and DEX are released due to the coating degradation. In vitro results showed that the multifunctional coating has strong antibacterial ability against both Escherichia coli and Staphylococcus aureus; it also improves human umbilical vein endothelial cell angiogenic ability and enhances rat bone marrow mesenchymal stem cell osteogenic differentiation activity. Furthermore, the in vivo rat subcutaneous infection model, chicken chorioallantoic membrane model, and rat femoral drilling model verify that the PEEK implant coated with the multifunctional coating has strong antibacterial and angiogenic ability and promotes the formation of new bone around the implant with a stronger bone−implant interface. Our findings indicate that DEX loaded on the Zn−Mg-MOF74 coating-modified PEEK implant with bacteriostasis, angiogenesis, and osteogenesis properties has great clinical application potential as bone graft materials.

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