Graphene oxide and mineralized collagen-functionalized dental implant abutment with effective soft tissue seal and romotely repeatable photodisinfection

Abstract

Grasping the boundary of antibacterial function may be better for the sealing of soft tissue around dental implant abutment. Inspired by 'overdone is worse than undone', we prepared a sandwich-structured dental implant coating on the percutaneous part using graphene oxide (GO) wrapped under mineralized collagen. Our unique coating structure ensured the high photothermal conversion capability and good photothermal stability of GO. The prepared coating not only achieved suitable inhibition on colonizing bacteria growth of Streptococcus sanguinis, Fusobacterium nucleatum and Porphyromonas gingivalis but also disrupted the wall/membrane permeability of free bacteria. Further enhancements on the antibacterial property were generally observed through the additional incorporation of dimethylaminododecyl methacrylate. Additionally, the coating with sandwich structure significantly enhanced the adhesion, cytoskeleton organization and proliferation of human gingival fibroblasts, which was effective to improve soft tissue sealing. Furthermore, cell viability was preserved when cells and bacteria were cultivated in the same environment by a coculture assay. This was attributed to the sandwich structure and mineralized collagen as the outmost layer, which would protect tissue cells from photothermal therapy and GO, as well as accelerate the recovery of cell activity. Overall, the coating design would provide a useful alternative method for dental implant abutment surface modification and functionalization.

Keywords: antibacterial; dental implant abutment; graphene oxide; mineralized collagen; soft tissue sealing.

Graphical abstract

Figure 1.

Schematic illustration of the preparation of the sandwich-structured dental implant abutment coating using GO wrapped under mineralized collagen to achieve a controllable antibacterial property based on suitable sealing of soft tissue

Figure 2.

(A) Raman spectra of AH-Ti, Ti-PDA, Ti-PDA-GO and Ti-PDA-GO-PDA. (B) FTIR spectrum of Ti-Col, Ti-GO-Col, Ti-GO-MCol and Ti-GO-MCol-D. (C) SEM images of PT-Ti, AH-Ti, Ti-PDA-GO, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D. Scale bars represent 20 μm. (D) EDX results of Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D

Figure 3.

(A) Atom force microscopy images of PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D. (B) Water contact angle of PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D. Error bars represent standard deviation of the mean for n = 4 (^#P < 0.05 compared with PT-Ti)

Figure 4.

(A–C). Photothermal curves of PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D under 808 nm laser irradiation of different power density (0.5, 1.0 and 1.5 W/cm²). (D) Infrared thermal images of PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D under 808 nm laser irradiation of 1.0 W/cm² power density. (E) Heating curves of Ti-GO-MCol-D for three laser on/off cycles (808 nm, 1 W/cm²)

Figure 5.

(A) SEM images of S. sanguinis, F. nucleatum and P. gingivalis on PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D after illumination. Scale bars represent 10 μm. (B) MTT assay of S. sanguinis, F. nucleatum and P. gingivalis cultured on PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D after illumination. (C–E). Cyclic antibacterial results of S. sanguinis, F. nucleatum and P. gingivalis on Ti-GO-MCol and Ti-GO-MCol-D after illumination from first to fifth cycle. Error bars represent standard deviation of the mean for n = 3 (^#P < 0.05 compared with PT-Ti, ⁺P < 0.05 compared with Ti-MCol, ^†P < 0.05 compared with Ti-GO-MCol)

Figure 6.

(A–B). Effect of modified coatings on the leakage G6PDH (A) and nucleic acid (B) from colonized bacteria regarding S. sanguinis, F. nucleatum and P. gingivalis before and after illumination. (C–D). Effect of modified coatings on the leakage G6PDH (C) and nucleic acid (D) from free bacteria regarding S. sanguinis, F. nucleatum and P. gingivalis before and after illumination. The tested G6PDH was collected from precipitation after centrifugation while nucleic was collected from supernatant after centrifugation. Error bars represent standard deviation of the mean for n = 3 (^$P < 0.05 compared with control, ^†P < 0.05 compared with Ti-GO-MCol, ^*P < 0.05)

Figure 7.

(A) The live/dead staining of HGFs on PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D after cultured for 1 and 4 h. Scale bars represent 250 μm. (B) The proliferation of HGFs on PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D surfaces for 1, 3, 5 and 7 days. (C) Immuno-fluorescence staining of adhesion-related proteins detected by confocal laser scanning microscopy on PT-Ti, Ti-MCol, Ti-GO-MCol and Ti-GO-MCol-D samples after incubation for 24 h. Scale bars represent 20 μm. (D) Quantification results of F-actin, vinculin, integrin β1 and relative cell spread area. Error bars represent standard deviation of the mean for n = 3 (^#P < 0.05 compared with PT-Ti)

Figure 8.

(A) The live/dead staining of HGFs on Ti-GO-MCol and Ti-GO-MCol-D before and after illumination after cultured for 24 h. Scale bars represent 250 μm. (B) The 3D confocal microscopy images of HGFs on Ti-GO-MCol and Ti-GO-MCol-D before and after illumination, as well as further culturing for one more period of 24 h. Scale bars represent 20 μm. (C) LDH activities in the medium after the contact between HGFs and different sample. Error bars represent standard deviation of the mean for n = 3 (^$P < 0.05 compared with control, ^†P < 0.05 compared with Ti-GO-MCol, ^*P < 0.05). (D) Immuno-fluorescence staining of adhesion-related proteins of HGFs on Ti-GO-MCol and Ti-GO-MCol-D before and after illumination. NIR represents illumination for 15 min and NIR-24 h represents that the samples continued to culture for another 24 h after illumination. Scale bars represent 20 μm

Figure 9.

(A) F-actin staining images of HGFs after cocultured with S. sanguinis for 4 h on different samples. Scale bars represent 20 μm. (B) SEM images of the coculture. Scale bars represent 20 μm