Effect of Surface Nanomodification of Titanium Implants on Adhesion, Bone Bonding, and Bacterial Aggregation of Gingival Epithelial Cells and Fibroblasts

Implant-supported dentures have become a major approach to edentulous/defective repair. Peri-implantitis is a major factor leading to implant failure. The emergence of antibacterial peptides has provided a novel idea for the study of antibacterial coatings on implant surfaces. The antibacterial peptide GL13K was modified onto the surface of titanium (Ti) by silanization with 3-chloropropyltriethoxysilane, and its physicochemical properties were characterized. After its coculture with Porphyromonas gingivalis (P. g) in vitro , the cell activity was detected, and the antibacterial properties were analyzed. After its coculture with gingival fibroblasts (GFs) in vitro , CCK-8 was adopted to detect cell proliferation and analyze cytotoxicity. After its coculture with gingival epithelial cells (GECs) and GFs in vitro , the adhesion was demonstrated by acridine orange staining and DAPI staining. The smooth Ti implant (S/T), the microgroove Ti implant (E/T), and the GL13K-modified microgroove Ti implant (GL13K/E/T) were implanted into the inferolateral aspect of the femoral condyle of the right posterior limb of healthy New Zealand rabbits. Four weeks after surgery, the levels of osteoprotegerin (OPG) and nuclear factor-kappa B ligand (RANKL) in the bone tissue around the implant were detected by immunohistochemistry. The results revealed that relative to the S/T and E/T materials, the surface roughness and contact angle of the GL13K/E/T material were enhanced, while the metabolic activity and colony count of P. g were decreased. S/T, E/T, and GL13K/E/T materials had no notable effect on the viability of GFs ( P > 0.05). Relative to the S/T material, the numbers of GECs and GFs attached to the surfaces of the E/T and GL13K/E/T materials were drastically increased ( P < 0.05). Furthermore, relative to the S/T group, OPG levels in the peri-implant bone tissues of the E/T and GL13K/E/T groups were increased, while the RANKL level was decreased ( P < 0.05). In contrast to group E/T, OPG in the peri-implant bone tissue of rabbits of the GL13K/E/T group was increased, while the RANKL was decreased ( P < 0.05). In summary, the Ti implant with a microgroove structure modified by the antibacterial peptide GL13K had an ideal antibacterial effect and promoted the adhesion and growth of GECs and GFs. In addition, the antibacterial peptide GL13K-modified Ti implant with a microgroove structure could promote early bone bonding.