Hydroxyapatite-collagen composites

Formation and properties of a synthetic bone composite hydroxyapatite-collagen. Journal of Biomedical Materials Research, 29, 803-10. 

In order to achieve the firm fixation of the artificial cornea to host tissues, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite were synthesized by a hydroxyapatite particles kneading method. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite material were studied. PVA-COL-HAp composites were successfully synthesized. A micro-porous structure of the PVA-COL-HAp could be introduced by hydrochloric acid treatment and the porosity could be controlled by the pH of the hydrochloric acid solution, the treatment time, and the crystallinity of the HAp particles. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-COL-HAp composites. This material showed potential for keratoprosthesis application. Further study such as a long-term animal study is now required [241]. 

Kikuchi, M., Itoh, S., Matsumoto, H.N., Koyama, Y., Takakuda, K., Shinomiya, K., and Tanaka, J., Fibrillogenesis of hydroxyapatite/collagen self-organized nano-composites, Key Eng. Mater., 567, 240-242, 2003. 

Huang Z, Feng Q, Yu B, Li S (2011) Biomimetic properties of an injectable chitosan/nano-hydroxyapatite/collagen composite. Mater Sd Eng C 31 683-687... 

In addition to drug delivery, collagen has been used in applications in the medical-pharmaceutical interface, including tissue engineering (i.e., composites of collagen with hydroxyapatite and tricalcium phosphate in bone grafts or as artificial valve and vessel substitutes) [417] and surgical sutures [418]. 

Cui, F.Z. et al.. Biodegradation of a nano-hydroxyapatite/collagen composite by peritoneal monocyte-macrophages. Cells Mater., 6,31,1996. 

Common long bone defect models include the rabbit radial model (most popular), rat femoral model, and the dog radial model. A composite bone scaffold consisting of nano-hydroxyapatite, collagen, and PLA was found to integrate the rabbit radial defect after 12 weeks [49]. The effect of bone morphogenetic protein was evaluated in the rat femoral defect model [4]. It should be noted that the rat model requires either internal or external fixation. In the dog model, ulnae fractures may occur, resulting in unexpected loss. 

Itoh S, Kikuchi M, Koyama Y et al (2002) Development of an artificial vertebral body using a novel biomaterial, hydroxyapatite/collagen composite. Biomaterieds 23 3919-3926... 

Solchaga LA, Dennis JE, Goldberg VM et al (1999) Hyaluronic acid-based polymers as cell carriers for tissue-engineered repair of bone and cartilage. J Orthop Res 17 205-213 Bakos D, Soldan M, Hernandez-Fuentes I (1999) Hydroxyapatite/collagen/hyaluronic acid composite. Biomaterials 20 191-195... 

Yunoki S, Ikoma T, Tsuchiya A et al (2007) Fabrication and mechaniceil and tissue ingrowth properties of unidirectionaHy porous hydroxyapatite/collagen composite. J Biomed Mater Res Part B Appl Biomater SOB 166-173... 

Bone tissue can be defined as a composite material. Collagen, one of the most common proteins of the body, represents almost 90% of the bone organic component and endows elasticity and impact resistance to the tissue. The second component, the inorganic one, stiffens and hardens the organic matrix and is formd in form of crystals from the hydroxyapatite mineral family [1-4]. 

Du, C., Cui, F.Z., Feng, Q.L, Zhu, X.D. and de Groot, K. (1998) Tissue response to nano-hydroxyapatite/collagen composite implants in marrow cavity. Journal of Biomedical Materials Research, 42, 540-8. 

Collagen (protein) and hydroxyapatite. Collagen aids the biomineralization process and adds flexibility to the composite. Hydroxyapatite provides hardness, strength and abrasion resistance. 

Liao, S., et al., 2005. A three-layered nano-carbonated hydroxyapatite/collagen/PLGA composite membrane for guided tissue regeneration. Biomaterials 26 (36), 7564—7571. Available at http //www.ncbi.nlm.nih.gOv/pubmed/16005963 (accessed 10.10.14.). 

Liao, S., Ngiam, M., Chan, C.K., Ramakiishna, S., 2009. Fabrication of nano-hydroxyapatite/ collagen/osteonectin composites for bone graft applications. Biomedical Materials 4, 025019. 

The design of an ideal bone graft that emulates bone s own structure and behaviour is stiU challenging. Owing to the composition and structural similarity to natural bone, most of the current investigations focus on nanocomposites, and particularly on the hydroxyapatite-collagen system. 

S. Itoh, M. Kikuchi, K. Takakuda, Y. Koyama, H.N. Matsumoto, S. Ichinose, J. Tanaka, T. Kawauchi, K. Shinomiya, The biocompatibility and osteoconductive activity of a novel hydroxyapatite/collagen composite biomateiial, and its function as a carrier of rhBMP-2, J. Biomed. Mater. Res. 54 (2001) 445-453. 

NIS 95] NISHIHARA K. and HIROTA K., Successful pressure sintering of hydroxyapatite-collagen composite . Advances in Science and Technology - Materials in Clinieal Applications, vol. 12, p. 297-304,1995. 

Bone is a porous tissue composite material containing a fluid phase, a calcified bone mineral, hydroxyapatite (HA), and organic components (mainly, collagen type). The variety of cellular and noncellular components consist of approximately 69% organic and 22% inorganic material and 9% water. The principal constiments of bone tissue are calcium (Ca ), phosphate (PO ), and hydroxyl (OH ) ions and calcium carbonate. There are smaller quantities of sodium, magnesium, and fluoride. The major compound, HA, has the formula Caio(P04)g(OH)2 in its unit cell. The porosity of bone includes membrane-lined capillary blood vessels, which function to transport nutrients and ions in bone, canaliculi, and the lacunae occupied in vivo by bone cells (osteoblasts), and the micropores present in the matrix. 

---