The aim of this study is to obtain pure natural hydroxyapatite (HAp) and tricalcium phosphate (TCP) from a Goniopora spp. and from hump coral (Porites cylindrica), both sourced from Australia. Due to the nature of the conversion process, commercial coralline HAp has retained coral or CaCO3, and the structure possesses both nano- and mesopores within the interpore trabeculae resulting in high dissolution rates. To overcome these limitations, a newly patented coral double-conversion technique has been developed. The current technique involves a two-stage application route where in the first-stage complete conversion of coral to pure HAp is achieved. In the second stage, a sol-gel-derived HAp nanocoating is directly applied to cover the meso- and nanopores within the intrapore material, while maintaining the large pores. Here, we specifically investigated the morphological changes and characterized these corals prior to and after conversion. For this purpose, four groups designated as C0, C1, C2, and C3 were used. C0 is Porites, Goniopora, and cylindrica; the original coral is calcium carbonate with aragonite structure that contains proteins and polysaccharides. C1 is coral cleaned under ultrasound in bleach diluted with water. C2 is coral converted to hydroxyapatite (HAp) by hydrothermal treatment method at 200 °C under pressure in the presence of ammonium biphosphate. C3 is obtained by coating C2 with sol-gel alkoxide-derived nanohydroxyapatite to obtain a more bioactive osteoconductive material and improve mechanical properties. All groups were characterized by XRD, EDAX, DTA/TGA, and SEM. The results showed that the biaxial strengths of the C2 and C3 were significantly higher than the original coral. The work also showed the advantages of the hydrothermal conversion method and the effect of the nanocoating which is expected to improve the final bioactivity through microstructural changes of the surfaces.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Price excludes VAT (USA)
Tax calculation will be finalised during checkout.
Ben-Nissan, B.: Natural bioceramics: from coral to bone and beyond. Curr Opinion Solid State Mater Sci. 7(4–5), 283–288 (2003)
Macha, I.J., Ozyegin, L.S., Oktar, F.N., Ben-Nissan, B.: Conversion of ostrich eggshells (Struthio camelus) to calcium phosphates. J Aust Ceram Soc. 51(1), 125–133 (2015)
Kel, D., Gökçe, H., Bilgiç, D., Ağaoğulları, D., Duman, I., Öveçoğlu, M.L., Kayalı, E.S., Kiyici, I.A., Agathopoulos, S., Oktar, F.N.: Production of natural bioceramic from land snails. Key Eng Mater. 493-494, 287–292 (2012)
Ozyegin, L.S., Sima, F., Ristoscu, C., Kiyici, I.A., Mihailescu, I.N., Meydanoglu, O., Agathopoulos, S., Oktar, F.N.: Sea snail: an alternative source for nano-bioceramic production. Key Eng Mater. 493-494, 781–786 (2012)
Rocha, J.H.G., Lemos, A.F., Agathopoulos, S., Valério, P., Kannan, S., Oktar, F.N., Ferreira, J.M.F.: Scaffolds for bone restoration from cuttlefish. Bone. 37(6), 850–857 (2005)
Agaogulları, D., Kel, D., Gokce, H., Duman, I., Öveçoğlu, M.L., Akarsubasi, A.T., Bilgic, D., Oktar, F.N.: Bioceramic production from sea urchins. Acta Phys Pol A. 121(1), 23–26 (2012)
Samur, R., Ozyegin, L.S., Agaogullari, D., Oktar, F.N., Agathopoulos, S., Kalkandelen, C., Duman, I., Ben-Nissan, B.: Calcium phosphate formation from sea urchine (brissus latecarinatus) via modified mechano-chemical (ultrasonic) conversation method. Metal. 52, 375–378 (2013)
Karacan, I., Gunduz, O., Ozyegin, L.S., Gökce, H., Ben-Nissan, B., Akyol, S., Oktar, F.N.: The natural nano-bioceramic powder production from organ pipe red coral (tubipora musica) by a simple chemical conversion method. J Aust Ceram Soc. 54(2), 317–329 (2018)
Oktar, F.N., Gokce, H., Gunduz, O., Sahin, Y.M., Agaogullari, D., Turner, I.G., Ozyegin, L.S., Ben-Nissan, B.: Bioceramic production from giant purple barnacle (megabalanus tintinnabulum). Key Eng Mater. 631, 137–142 (2015)
Green, D.W., Ben-Nissan, B., Yoon, K.S., Milthorpe, B., Jung, H.S.: Bioinspired materials for regenerative medicine: going beyond the human archetypes. J Mater Chem B. 4(14), 2396–2406 (2016)
Laine, J., Labady, M., Albornoz, A., Yunes, S.: Porosities and pore sizes in coralline calcium carbonate. Mater Charact. 59(10), 1522–1525 (2008)
Roy, D., Linnehan, S.: Hydroxyapatite formed from coral skeletal carbonate by hydrothermal exchange. Nature. 247(438), 220–222 (1974)
Hing, K.A., Best, S.M., Tanner, K.E., Bonfield, W., Revell, P.A.: Quantification of bone ingrowth within bone-derived porous hydroxyapatite implants of varying density. J Mater Sci Mater Med. 10(10/11), 663–670 (1999)
Ben-Nissan B.: Discovery and development of marine biomaterials, In Functional Marine Biomaterials, Properties and Applications, Chapter1, Edited by Se-Kwon Kim, Woodhead Publishing, Print Book ISBN : 9781782420866, 3–32 (2015)
Chou, J., Valenzuela, S., Bishop, D., Ben-Nissan, B., Milthorpe, B.: Strontium- and magnesium-enriched biomimetic beta-TCP macrospheres with potential for bone tissue morphogenesis. J Tissue Eng Regen Med. 8(10), (2012)
Chai, C.S., Ben-Nissan, B.: Bioactive nanocrystalline sol-gel hydroxyapatite coatings. J Mater Sci Mater Med. 10(8), 465–469 (1999)
Gross, K.A., Chai, C.S., Kannangara, G.S.K., Ben-Nissan, B., Hanley, L.: Thin hydroxyapatite coatings via sol–gel synthesis. J Mater Sci Mater Med. 9(12), 839–843 (1998)
Ben-Nissan, B., Choi, A.H.: Sol-gel production of bioactive nanocoatings for medical applications. Part 1: an introduction. Future Medicine Ltd. 1(3), 311–319 (2006)
Zreiqat, H., Valenzuela, S.M., Ben-Nissan, B., Roest, R., Knabe, C., Radlanski, R.J.: The effect of surface chemistry modification of titanium alloy on signaling pathways in human osteoblasts. Biomaterials. 26(36), 7579–7586 (2005)
Elsinger, E.C., Leal, L.: Coralline hydroxyapatite bone graft substitutes. The Journal of Foot and Ankle Surgery. 35(5) (9–10), 396–399 (1996)
Songer, M., Baskin, D., Kabins, M., Reynolds, A., Zak, P.: Prospective randomized comparison of ProOsteon 200 Coralline Hydroxyapatite bone graft substitute versus iliac crest autograft in anterior cervical fusions. Spine J. 2(5), 64–64 (2002)
Markel, D.C., Guthrie, S.T., Wu, B., Song, Z., Wooley, P.H.: Characterization of the inflammatory response to four commercial bone graft substitutes using a murine biocompatibility model. J Inflamm Res. 2012, 13–18 (2018)
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Akyol, S., Ben Nissan, B., Karacan, I. et al. Morphology, characterization, and conversion of the corals Goniopora spp. and Porites cylindrica to hydroxyapatite. J Aust Ceram Soc 55, 893–901 (2019). https://doi.org/10.1007/s41779-018-00304-4