This study aimed
to evaluate the bioactivity of poly(ether
ether
ketone) (PEEK) after surface modification by persistent photoconductive
strontium titanate (SrTiO3) magnetron sputtering and ultraviolet
(UV) C irradiation. According to the different modifications, the
PEEK specimens were randomly divided into five groups (n = 38/group): PEEK, Sr100-PEEK, Sr200-PEEK, UV/PEEK, and UV/Sr200-PEEK.
Then, the specimens of Sr100-PEEK and Sr200-PEEK groups were, respectively,
coated with 100 and 200 nm thickness photocatalyst SrTiO3 on the PEEK surface by magnetron sputtering. Subsequently, UV–C
light photofunctionalized the specimens of PEEK and Sr200-PEEK groups
to form UV/PEEK and UV/Sr200-PEEK groups. The specimens were characterized
by a step meter, scanning electron microscopy (SEM), atomic force
microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), and
a water contact angle meter. The release test of the Sr ion was performed
by inductively coupled plasma mass spectrometry (ICP–MS). In
vitro study, osteogenic activity (MC3T3-E1 osteoblast-like cells)
and epithelial and connective tissue attachment (gingival epithelial
cells GE1 and fibroblasts NIH3T3) were analyzed in five groups. Surface
morphology of the specimens was changed after coating, and the Sr
content on the Sr-PEEK surface was increased with increasing coating
thickness. In addition, the contact angle was increased significantly
after magnetron sputtering. After UV–C photofunctionalization,
the content of surface elements changed and the contact angle was
decreased. The release of Sr ion was sustained, and the final cumulative
release amount did not exceed the safety limit. In vitro experiments
showed that SrTiO3 improved the cell activity of MC3T3-E1
and UV–C irradiation further enhanced the osteogenic performance
of PEEK. Besides, UV–C irradiation also significantly promoted
the cell viability, development, and expression of adhesion proteins
of GE1 and NIH3T3 on PEEK. The present investigation demonstrated
that nano SrTiO3 coating with UV–C photofunctionalization
synergistically enhanced the osteogenic properties and soft tissue
sealing function of PEEK in vitro.