Nano-hydroxyapatite (n-HAp) is similar to human bone mineral in structure and biochemistry and is, therefore, widely used as bone biomaterial and a drug carrier. Further, n-HAp composite scaffolds have a great potential role in bone regeneration. Loading bioactive factors and drugs onto n-HAp composites has emerged as a promising strategy for bone defect repair in bone tissue engineering. With local delivery of bioactive agents and drugs, biological materials may be provided with the biological activity they lack to improve bone regeneration. This review summarizes classification of n-HAp composites, application of n-HAp composite scaffolds loaded with bioactive factors and drugs in bone tissue engineering and the drug loading methods of n-HAp composite scaffolds, and the research direction of n-HAp composite scaffolds in the future is prospected.
Nano-hydroxyapatite/collagen (nHAC) is a new type of bone tissue engineering scaffold material. To speed up the new bone formation of nHAC, this study used concentrated growth factor (CGF) and nHAC in combination to repair rabbit mandibular defects. nHAC/CGF and nHAC were implanted into rabbit mandibles, and X-ray, Micro-CT, HE and Masson staining, immunohistochemical staining and biomechanical testing were performed at 8, 16 and 24 weeks after surgery. The results showed that as the material degraded, the rate of new bone formation in the nHAC/CGF group was better than that in the nHAC group. The results of the HE and Masson staining showed that the bone continuity or maturity of the nHAC/CGF group was better than that of the nHAC group. Immunohistochemical staining showed that OCN expression gradually increased with time. The nHAC/CGF group showed significantly higher BMP2 than the nHAC group at 8 weeks and the difference gradually decreased with time. The biomechanical test showed that the compressive strength and elastic modulus of the nHAC/CGF group were higher than those of the nHAC group. The results suggest that nHAC/CGF materials can promote new bone formation, providing new ideas for the application of bone tissue engineering scaffold materials in oral clinics.
Bone damage as a consequence of disease or trauma is a common global occurrence. For bone damage treatment - bone implant materials are necessary across three classifications of surgical intervention (i.e. fixation, repair, and replacement). Many types of bone implant materials have been developed to meet the requirements of bone repair. Among them, polyether ether ketone (PEEK) has been considered as one of the next generation of bone implant materials, owing to its advantages related to good biocompatibility, chemical stability, X-ray permeability, elastic modulus comparable to natural bone, as well as the ease of processing and modification. However, as PEEK is a naturally bioinert material, some modification is needed to improve its integration with adjacent bones after implantation. Therefore, it has become a very hot topic of biomaterials research and various strategies for the modification of PEEK including blending, 3D printing, coating, chemical modification and the introduction of bioactive and/or antibacterial substances have been proposed. In this systematic review, the recent advances in modification of PEEK and its application prospect as bone implants are summarized, and the remaining challenges are also discussed.
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