Biologically Inspired Collagen/Apatite Composite Biomaterials for Potential Use in Bone Tissue Regeneration-A Review

Abstract

Type I collagen and nanocrystalline-substituted hydroxyapatite are the major components of a natural composite-bone tissue. Both of these materials also play a significant role in orthopedic surgery and implantology; however, their separate uses are limited; apatite is quite fragile, while collagen's mechanical strength is very poor. Therefore, in biomaterial engineering, a combination of collagen and hydroxyapatite is used, which provides good mechanical properties with high biocompatibility and osteoinduction. In addition, the porous structure of the composites enables their use not only as bone defect fillers, but also as a drug release system providing controlled release of drugs directly to the bone. This feature makes biomimetic collagen-apatite composites a subject of research in many scientific centers. The review focuses on summarizing studies on biological activity, tested in vitro and in vivo.

Keywords: biocomposite; biomimetic material; bone regeneration; collagen; hydroxyapatite; scaffold.

Figure 1

The multi-scale structure of natural bone.

Figure 2

SEM of scaffolds. (a,b) Pure collagen. (c,d) Col/mHA (collagen/hydroxyapatite-microsphere). Scale bars: 100 μm (a,c), 20 μm (b,d). Reprinted from [44] with permission from Elsevier.

Figure 3

Detailed schematic illustration of the MgHA/Coll (type I collagen matrix with magnesium-doped-hydroxyapatite nanophase) hybrid scaffold’s development: (A) pH-driven, bioinspired biomineralization process; (B) MgHA/Coll crosslinking with ribose scaffolds in pre and post-glycation processes. Reprinted from [57] with permission from Elsevier.

Figure 4

HE-stained histological section (×100) of HAp/Col composite implanted into a beagle’s tibia for 12 weeks. Triangles indicate elongated cells, and arrowheads multinucleated giant cells. Reprinted from [40] with permission from Elsevier.

Figure 5

Confocal microscopy of osteoblast cells cultured on microsphere staining with DNA dye YOYO-1 (HAp: hydroxyapatite, OB: osteoblast; 4 days after seeding). Reprinted from [47] with permission from Elsevier.

Figure 6

Results of X-ray evaluation. The scores improved over time during the follow-up period in both groups. At each time point, the score in the HAp/Col group was higher than that in the β-TCP group. Reprinted from [74] with permission from Elsevier.

Figure 7

Schematic diagram of the experimental procedure for the multifunctionalization of the scaffolds after 3D-printing by using a simple coating process (PLA: polylactide; MH: minocycline hydrochloride; cHA: citrate-hydroxyapatite nanoparticles). Reprinted from [98] with permission from Elsevier.