Graphene and its Derivatives for Bone Tissue Engineering: In Vitro and In Vivo Evaluation of Graphene-Based Scaffolds, Membranes and Coatings

Abstract

Bone regeneration or replacement has been proved to be one of the most effective methods available for the treatment of bone defects caused by different musculoskeletal disorders. However, the great contradiction between the large demand for clinical therapies and the insufficiency and deficiency of natural bone grafts has led to an urgent need for the development of synthetic bone graft substitutes. Bone tissue engineering has shown great potential in the construction of desired bone grafts, despite the many challenges that remain to be faced before safe and reliable clinical applications can be achieved. Graphene, with outstanding physical, chemical and biological properties, is considered a highly promising material for ideal bone regeneration and has attracted broad attention. In this review, we provide an introduction to the properties of graphene and its derivatives. In addition, based on the analysis of bone regeneration processes, interesting findings of graphene-based materials in bone regenerative medicine are analyzed, with special emphasis on their applications as scaffolds, membranes, and coatings in bone tissue engineering. Finally, the advantages, challenges, and future prospects of their application in bone regenerative medicine are discussed.

Keywords: bone tissue engineering; coatings; graphene; membranes; scaffolds.

FIGURE 1

SEM image of (A) the porous structure in HA/rGO-6/0.3 composite scaffold, and (B) (D) the pore structure, (C) cross-sectional structure of hole wall, (E) pore wall structure and (F) enlarged view of the cross-section of hole wall. (G) Pore structure of HA/rGO-6/0.3 and EDS (H) Ca, (I) P (J) C mapping images of Figure 2G. Reproduced from Zhou et al. (2019) with permission from Copyright 2019 American Chemical Society.

FIGURE 2

In vivo evaluation of the scaffolds using the critical-sized defect (A, C) Three-dimensional reconstruction and (B, D) coronal section analysis of the defect areas at 4 and 12 weeks (A, B) New bone was formed in the four groups at 4 weeks, and (C, D) almost complete healing of the bone defects was observed in 0.1 and 0.2% GO−Col−Ap groups at 12 weeks. Dotted red circle: defect area. Reproduced from Zhou et al. (2018) with permission from Copyright 2018 American Chemical Society.

FIGURE 3

Schematic illustration of the preparation and in vivo application of the GO-collagen tissue engineering chamber in a rat groin model. GO and collagen were dissolved, blended and injected into molds to obtain GO-collagen scaffolds with disc shape and hollow cylindrical shape. After the cross-linking process, GO-collagen scaffolds were fabricated to make a tissue engineering chamber. Then, the BMSCs-gelatin grafts were encased in the GO-collagen chamber and implanted into the rat groin area, with vessels traversing through the graft. Reproduced from Fang et al. (2020) with permission from Copyright 2020 Ivyspring International Publisher.

FIGURE 4

The bone regeneration 8 weeks after surgery. (A) Micromorphometric analysis of treated calvarial defects including superficial, interior, coronal, and sagittal section views of micro-CT images taken at the eighth week after surgery. (B) Micromorphometric bone parameters including bone volume fraction and bone mineral density analyzed after 8 weeks of surgery. Note that both the bone volume fraction and mineral density of the MGH membranes group are higher than the rest of the groups analyzed. (C) Van Gieson’s staining of calvarial undecalcified sections after 8 weeks of implantation. Low-magnification histological images (left) showed osteogenesis of the testing groups with/without barrier membranes (M). High magnification histology (right) showed boxed areas in the left images, both the lateral margin and center region of defects. In the MGH membrane group, the newly formed bone (NB) exhibited a mature lamellar bone structure with external cortical bone (E), diploic bone (D), and internal cortical bone (I) all discernable. Triangles denote the original bone margins. Scale bars, 250 μm. Reproduced from Lu et al. (2016) with permission from Copyright 2016 Wiley.

FIGURE 5

(A) General view of PLGAand PLGA-GO membranes and (B–F) surgical procedure of interposition of PLGAand PLGA-GO membranes in the rabbit supraspinatus tendon repair model. Reproduced from Su et al. (2019) with permission from Copyright 2019 Dove Medical Press Ltd.

FIGURE 6

(A) Photo of the pure Ti, PDA modified Ti (PDA-Ti), and GO-wrapped Ti scaffolds. (B) SEM micrographs showing micropores in the Ti scaffold. (C) PDA ad-layer was coated on the surface of the Ti scaffold. (D) GO uniformly covered on the PDA-Ti scaffold. (E) Magnified image of (D), showing wrinkled GO nanosheets wrapped in the pores of the Ti scaffold. Reproduced from Han et al. (2018b) with permission from Copyright 2018 Royal Society of Chemistry.

FIGURE 7

Schematic of the experimental protocol for the fabrication of GO-Cu-coated CPC scaffolds. (A) The pattern of GO. (B) Premature Cu nanoparticles on GO film. (C) Mature nanoparticles on GO film. (D) GO-Cu coated porous CPC scaffold. Reproduced from Zhang et al. (2016) with permission from Copyright 2016 Wiley.