Kyushu University Academic Staff Educational and Research Activities Database
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Kishida Ryo Last modified date:2024.05.02

Graduate School

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Official website of Department of Biomaterials, Kyushu University .
Academic Degree
Ph D
Country of degree conferring institution (Overseas)
Field of Specialization
Biomaterials, Computational Chemistry
Total Priod of education and research career in the foreign country
Research Interests
  • Engineering porous materials and cements mimicking bone composition
    keyword : carbonate apatite, bone substitute, bone cement, setting reaction, porous materials
Academic Activities
1. Maab Elsheikh, Ryo Kishida, Koichiro Hayashi, Akira Tsuchiya, Masaya Shimabukuro, Kunio Ishikawa, Effects of pore interconnectivity on bone regeneration in carbonate apatite blocks, Regenerative Biomaterials, 10.1093/rb/rbac010, 9, 9, 2022.04, Porous architecture in bone substitutes, notably the interconnectivity of pores, is a critical factor for bone ingrowth. However, controlling the pore interconnectivity while maintaining the microarchitecture has not yet been achieved using conventional methods, such as sintering. Herein, we fabricated a porous block using the crystal growth of calcium sulfate dihydrate, and controlled the pore interconnectivity by limiting the region of crystal growth. The calcium sulfate dihydrate blocks were transformed to bone apatite, carbonate apatite (CO3Ap) through dissolution–precipitation reactions. Thus, CO3Ap blocks with 15% and 30% interconnected pore volumes were obtained while maintaining the microarchitecture: they were designated as CO3Ap-15 and CO3Ap-30, respectively. At 4 weeks after implantation in a rabbit femur defect, new bone formed throughout CO3Ap-30, whereas little bone was formed in the center region of CO3Ap-15. At 12 weeks after implantation, a large portion of CO3Ap-30 was replaced with new bone and the boundary with the host bone became blurred. In contrast, CO3Ap-15 remained in the defect and the boundary with the host bone was still clear. Thus, the interconnected pores promote bone ingrowth, followed by replacement of the material with new bone. These findings provide a useful guide for designing bone substitutes for rapid bone regeneration. <p></p>.
2. Pery Freitas, Ryo Kishida, Koichiro Hayashi, Akira Tsuchiya, Masaya Shimabukuro, Kunio Ishikawa, Fabrication and histological evaluation of porous carbonate apatite blocks using disodium hydrogen phosphate crystals as a porogen and phosphatization accelerator, Journal of Biomedical Materials Research Part A, 10.1002/jbm.a.37374, 110, 6, 1278-1290, 110, 6, 1278-1290, 2022.02.
3. Ryo Kishida, Maab Elsheikh, Koichiro Hayashi, Akira Tsuchiya, Kunio Ishikawa, Fabrication of highly interconnected porous carbonate apatite blocks based on the setting reaction of calcium sulfate hemihydrate granules, Ceramics International, 10.1016/j.ceramint.2021.03.324, 47, 14, 19856-19863, 47, 19856, 2021.04, [URL], Interconnected porous carbonate apatite (CO3Ap) blocks that emulate cancellous bone have potential as an alternative to autografts. The present study aimed to evaluate the feasibility of fabricating a block via a stepwise compositional transformation to CO3Ap through dissolution-precipitation reactions of an interconnected porous calcium sulfate dihydrate (CSD) block, which was obtained by the setting reaction of calcium sulfate hemihydrate (CSH) granules. Exposure of the CSH granules to water resulted in a setting reaction. However, the gaps between the granules were clogged, preventing the fabrication of interconnected porous structures. Removing the water in the gaps using filter paper was beneficial in avoiding gap clogging and in fabricating interconnected porous CSD blocks. Although the CSD blocks transformed into CaCO3 blocks, which maintained the interconnected porous structure through a dissolution-precipitation reaction in a Na2CO3 solution, their mechanical strength was quite low (diametral tensile strength: DTS = 75 kPa). In contrast, a CaCO3 block with a much greater mechanical strength (DTS = 0.98 MPa) was fabricated when a calcium sulfate anhydrous block made via the heat treatment of the CSD block was used as a precursor. The CaCO3 block transformed into a CO3Ap block (DTS = 2.1 MPa), maintaining the interconnected porous structure through a dissolution-precipitation reaction when immersed in a Na2HPO4 solution. The CO3Ap block had macropores initiated by the gaps between the granules and micropores created by the setting reaction of CSH granules and the dissolution-precipitation reactions to form CO3Ap. The results obtained in the present study demonstrate that this method is useful for fabricating interconnected porous CO3Ap blocks..
Membership in Academic Society
  • The Ceramic Society of Japan
  • Japanese Society for Pigment Cell Research
  • The Japanese Society of Applied Physics
  • The Physical Society of Japan
  • Japanese Society for Biomaterials
  • The Japanese Society for Dental Materials and Devices