Hydroxyapatite/tannic acid composite coating formation based on Ti modified by TiO2 nanotubes.

Oxidative stress induced by reactive oxygen species (ROS) overproduction and accumulation would hinder the osseointegration process at the bone-implant interface, leading to a higher rate of implant failure. To endow titanium (Ti) implants with antioxidant activity, we developed a coating approach mediated by tannic acid (TA)-Ca2+ coordination complexation. A hydroxyapatite (HA)/TA composite coating was prepared, based on Ti substrates modified by anodized and annealed titanium dioxide (TiO2) nanotube arrays. The results reveal that highly ordered TiO2 nanotubes with a diameter of 142.23 ±â€¯14.52 nm and a length of 374.17 ±â€¯42.47 nm were fabricated on the Ti substrate and the XRD pattern shows the TiO2 anatase phase after annealing at 450 ℃. TA-Ca complexes were formed on the surface of TiO2 nanotubes by immersing the constructs into the mixed solution of TA and CaCl2, where they are served as calcium sites for the HA growth by later phosphorylation. The HA nanoparticles present needle-shape with the diameter of 18 ∼ 20 nm. The total antioxidant capacity assay was employed to confirm the antioxidant effect of the HA/TA composite coating. The results indicate that it has a persistent and strong antioxidative activity. In vitro cytological test results show that HA/TA coating exhibits good cytocompatibility for osteoblasts proliferation and adhesion.

The surface modification of eguus asinus augment fibroblast adhesion and proliferation on silk fibroin materials / 生物医学工程学杂志

Eguus asinus is one of the rare Chinese drugs famous for promoting blood circulation. In this experiment, it was employed to modify the silk fibroin (SF) by physical blending. Mouse embryonic fibroblasts NIH-3T3 were seeded on pure and modified SF surfaces. The morphological changes of cell on SF surfaces were characterized by optical microscope images. The cell adhesion diameter, the attachment force (F) of a single cell and cell proliferation on SF surfaces were measured by micropipette aspiration system and MTT assay. The results indicated that the fibroblasts seeded on modified SF had larger cell adhesion area, stronger initial attachment force and higher cell proliferation than did the pure SF. In conclusion, eguus asinus improved the adhesion and proliferation of fibroblasts on SF. The research promoted the further use of Chinese drug eguus asinus in tissue engineering.