Abstract:

Objective To investigate the biological effects and antibacterial properties of TiO₂ nanotubes loaded baicalin-chitosan composite coating. Methods ①TiO₂ nanotubes were fabricated on the surface of titanium sheet and divided into four groups:TiO₂, TiO₂+BC, TiO₂+CS, TiO₂+BC+CS. The physicochemical properties of each group were detected by scanning electron microscope, surface contact angle and high performance liquid chromatography. ②BMSCs were co-cultured with titanium tablets of each group, and the effects of baicalin-chitosan composite coating on adhesion, proliferation and osteogenic differentiation of BMSCs were evaluated by CCK-8 adhesion proliferation test, live/dead cell staining, ALP activity detection, alizarin red S staining and cell mineralization quantitative detection. ③The titanium sheets of each group were co-cultured with S. aureus and E. coli, and the antibacterial properties of the coating were tested by zone of inhibition test, spread plate method and turbidimetric method. Results ①Under scanning electron microscope, it was observed that chitosan could cover the TiO₂ nanotubes and form a membrane-like structure on the surface. The contact angle test results showed that the contact angle of TiO₂+BC+CS group was larger than that of TiO₂ group (P<0.01), and the hydrophilicity was worse, but there was no difference with TiO₂+BC group (P>0.05). High performance liquid chromatography (HPLC) showed that TiO₂+BC+CS group could delay the release of baicalin and achieve a slow release effect. ②BMSCs were co-cultured with titanium tablets of each group. The cell adhesion test showed that the number of cells in TiO₂+BC+CS group was higher than that in TiO₂ group at 4 h (P<0.05). CCK-8 proliferation detection showed that the cell proliferation rate of TiO₂+BC+CS group was faster than that of TiO₂+BC group and TiO₂+BC group at 7 days (P<0.05). The staining results of live/dead cells showed that there were a large number of green fluorescent live cells that attached to the surface of each group, and the cell morphology was similar. The ALP activity of TiO₂+BC and TiO₂+BC+CS groups was higher at 4 d, and the ALP activity of TiO₂+BC+CS group was the best at 7 d (P<0.05). The results of alizarin red S staining showed that TiO₂+BC+CS group had the most red particles and the color was darker. At 14 and 21 days, the cell mineralization level of TiO₂+BC+CS group was the highest (P<0.05). ③TiO₂+BC+CS group had obvious inhibition zone around it, and the turbidity of bacterial solution in TiO₂+CS group and TiO₂+BC+CS group was lower than that in TiO₂ group and TiO₂+BC group (P<0.05). Conclusion The baicalin-chitosan composite coating is beneficial to the early adhesion, proliferation and osteogenic differentiation of BMSCs and has good antibacterial properties.

Key words: baicalin, chitosan, biological evaluation, antibacterial properties