Fabrication of porous gehlenite coating on Al2O3-ZrO2-SiC composite ceramics and its in vitro biological activities.

Porous gehlenite coatings on Al2O3-ZrO2-SiC composite ceramics were prepared by electro-spraying technique combined with reactive sintering method. The influences of gehlenite coating on the mechanical property of the ceramics and biological activity of the coating were investigated. The results indicated that the gehlenite coating has limited influences on flexural strength and fracture toughness of the ceramics, and the coating has elastic modulus of 82 GPa, hardness of 2.2 GPa, and adhesive strength of 1512 mN, suggesting its potential application in load-bearing ceramic implants. Simulated body fluid soaking test, CCK-8 and alkaline phosphatase activity assay demonstrated that the porous gehlenite coating has strong mineralization ability, which promotes proliferation and differentiation of MC3T3-E1 cells. These excellent biological performances can be attributed to the synergistic effect of the porous surface of the coating and its release of Ca2+ and Si4+.

Fabrication of hexagonal boron carbonitride nanoplates using for in vitro photodynamic therapy and chemo therapy.

Carbon nanomaterials and boron nitride nanomaterials have been proved to be very potential for biomedical applications. However, as an analog of them, boron carbonitride nanomaterials are rarely reported in biomedical field. In this study, the fabrication of visible light-responsive boron carbonitride nanoplates (BCNNPs) and their application in photodynamic therapy and chemo therapy were demonstrated. BCNNPs with an average size of 46 nm were fabricated via hydrogen peroxide treatment from bulk BCN. Cytotoxicity tests showed that the as-prepared BCNNPs are biocompatible and have no cytotoxicity to human breast cancer cells and human hepatocyte carcinoma cells. After conjunction with doxorubicin and folic acid, the BCNNPs were adopted as a targeted drug carrier, presenting pH-responsive release and tumor-targeting property for chemo therapy. Moreover, under certain intensity of visible light irradiation (45 mW/cm2), the BCNNPs can generate reactive oxygen species including superoxide radical, hydroxyl radical and singlet oxygen, so that synergistic photodynamic/chemo therapy effects were achieved. This work may be a groundbreaking discovery for utilizing BCNNPs as photosensitizer for photodynamic therapy and drug carrier for chemo therapy.

Synthesis of boron carbonitride nanosheets using for delivering paclitaxel and their antitumor activity.

As a structural analog of graphene and boron nitride, hexagonal boron carbonitride nanosheets (BCNNSs) are supposed to be a potential drug deliverer. In the present work, an improved solid-state reaction method combined with ultrasonic exfoliating was reported for preparing BCNNSs. Vapor-solid (VS) mechanism was proposed to be responsible for the formation of BCNNSs. The BCNNSs were further modified by DSPE-mPEG-5000 to improve their dispersion in aqueous solution. It was found that the BCNNSs-PEG nanocomplex could be efficiently taken in by MDA-MB-231 breast cancer cells evidenced by inverted fluorescence microscopy. The PEGylated BCNNSs showed an outstanding ability to load paclitaxel through π-π interaction and hydrophobic interaction, and BCNNSs-PEG-loaded paclitaxel presented higher cytotoxicity in comparison with free paclitaxel. BCNNSs may become a promising candidate for delivering paclitaxel and other hydrophobic drugs.