Surface Bandgap Engineering of Nanostructured Implants for Rapid Photothermal Ion Therapy of Bone Defects

• Published in: Advanced healthcare materials 2022-11, Vol.11 (22), p.e2200998-n/a
• Main Authors: Xue, Yang, Zhang, Lan, Liu, Fuwei, Zhao, Yiwei, Zhou, Jianhong, Hou, Yan, Bao, Han, Kong, Liang, Ma, Fei, Han, Yong
• Format: Article
• Language: English
• Subjects: Bone growth; Bone implants; bone regeneration; Defects; Density functional theory; Doping; Energy gap; Gene expression; Growth factors; Humans; I.R. radiation; implants; In vitro methods and tests; In vivo methods and tests; Ions; Light irradiation; Microenvironments; Nanostructure; Near infrared radiation; Orthopedics; Osseointegration; Osteoblasts; Osteogenesis; Oxidation; photothermal therapy; Prostheses and Implants; Regeneration; Regeneration (physiology); signaling pathways; Silicon - chemistry; Smad protein; surface bandgap engineering; Surgical implants; Titanium; Titanium - chemistry; Titanium dioxide; Valence band
• ISSN: 2192-2640; 2192-2659
• DOI: 10.1002/adhm.202200998

Bone defects are seriously threatening the health of orthopedics patients and it is difficult for implants to accelerate bone regeneration without using bone growth factors. Herein, a fast photothermal ion therapeutic strategy is developed based on the bandgap engineering of nanostructured TiO2 through (Si/P)‐dual elemental doping by micro‐arc oxidation treatment of titanium implants. The (Si/P)‐dual doping can tune the surface bandgap structure of TiO2 by decreasing bandgap and broadening valence band simultaneously, which is confirmed by density functional theory calculations. It not only endows the implants with a mildly photothermal effect under near‐infrared (NIR) light irradiation, but also creates an (Si/P) ion‐rich microenvironment around the implants. This photothermal ion microenvironment can tune the behaviors of osteoblasts by promoting p38/Smad and ERK signaling pathways of osteoblasts, thus significantly upregulating the expression of osteogenesis genes by the synergistic action of mild photothermal stimulation and increased release of Si/P ions. The in vivo results are also in good agreement with in vitro tests, i.e., under NIR light irradiation, the photothermally responsive TiO2 enhances the bone formation and osteointegration with implants. Therefore, this kind of photothermal ion strategy is a promising remote and noninvasive therapeutic mode for promoting bone regeneration of Ti implants. A fast photothermal ion therapy for bone defects is proposed using nanostructured TiO2 with (Si/P)‐dual doping. TiO2 is micro/nanoporous and has tuned bandgap structure, showing outstanding photothermal response. The synergistic action of mild photothermal stimulation and supplement of Si/P ions promotes p38/Smad and ERK signaling pathways of osteoblasts, upregulating osteogenesis genes expression in vitro and osteointegration in vivo.