{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T09:50:25Z","timestamp":1776851425890,"version":"3.51.2"},"reference-count":30,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2021,10,21]],"date-time":"2021-10-21T00:00:00Z","timestamp":1634774400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100015045","name":"Kaohsiung Armed Forces General Hospital","doi-asserted-by":"publisher","award":["Grant 109-06"],"award-info":[{"award-number":["Grant 109-06"]}],"id":[{"id":"10.13039\/501100015045","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>The tibia of New Zealand White rabbits was used as a model of critical bone defects to investigate a new design of composite scaffold for bone defects composed of dual materials. The all-in-one design of a titanium alloy (Ti-6Al-4V) scaffold comprised the structure of a bone plate and gradient porosity cage. Hydroxyapatite (HAp), a biodegradable material, was encapsulated in the center of the scaffold. The gradient pore structure was designed with 70%-65%-60%-55%-50% porosity, since the stresses could be distributed more uniformly when the all-in-one scaffold was placed on the bone contact surface. By covering the center of the scaffold with a low strength of HAp to contact the relatively low strength of bone marrow tissues, the excessive stiffness of the Ti-6Al-4V can be effectively reduced and further diminish the incidence of the stress shielding effect. The simulation results show that the optimized composite scaffold for the 3D model of tibia had a maximum stress value of 27.862 MPa and a maximum strain of 0.065%. The scaffold prepared by selective laser melting was annealed and found that the Young\u2019s coefficient increased from 126.44 GPa to 131.46 GPa, the hardness increased from 3.9 GPa to 4.12 GPa, and the strain decreased from 2.27% to 1.13%. The result demonstrates that the removal of residual stress can lead to a more stable structural strength, which can be used as a reference for the design of future clinical tibial defect repair scaffolds.<\/jats:p>","DOI":"10.3390\/mi12111294","type":"journal-article","created":{"date-parts":[[2021,10,22]],"date-time":"2021-10-22T00:22:02Z","timestamp":1634862122000},"page":"1294","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["A New Design of Porosity Gradient Ti-6Al-4V Encapsulated Hydroxyapatite Dual Materials Composite Scaffold for Bone Defects"],"prefix":"10.3390","volume":"12","author":[{"given":"Cheng-Tang","family":"Pan","sequence":"first","affiliation":[{"name":"Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wen-Hsin","family":"Hsu","sequence":"additional","affiliation":[{"name":"Department of Emergency Medicine, Kaohsiung Armed Forces General Hospital, Kaohsiung 80284, Taiwan"},{"name":"Institute of Medical Science and Technology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu-Shun","family":"Cheng","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4411-044X","authenticated-orcid":false,"given":"Zhi-Hong","family":"Wen","sequence":"additional","affiliation":[{"name":"Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wen-Fan","family":"Chen","sequence":"additional","affiliation":[{"name":"Institute of Medical Science and Technology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1097\/00003086-198007000-00045","article-title":"The optimum pore size for the fixation of porous-surfaced metal implants by the ingrowth of bone","volume":"150","author":"Bobyn","year":"1980","journal-title":"Clin. 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