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Hayashi K, Kishida R, Tsuchiya A, Ishikawa K. Effects of Space Dimensionality within Scaffold for Bone Regeneration with Large and Oriented Blood Vessels. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7518. [PMID: 38138660 PMCID: PMC10744811 DOI: 10.3390/ma16247518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 11/30/2023] [Accepted: 12/02/2023] [Indexed: 12/24/2023]
Abstract
The internal structure of the scaffolds is a key factor for bone regeneration. In this study, we focused on the space dimensionality within the scaffold that may control cell migration and evaluated the effects on the size and orientation of blood vessels and the amount of bone formation in the scaffold. The carbonate apatite scaffolds with intrascaffold space allowing one-dimensional (1D), two-dimensional (2D), or three-dimensional (3D) cell migration were fabricated by 3D printing. These scaffolds had the same space size, i.e., distances between the struts (~300 µm). The scaffolds were implanted into the medial condyle of rabbit femurs for four weeks. Both the size and orientation degree of the blood vessels formed in the scaffolds allowing 1D cell migration were 2.5- to 4.0-fold greater than those of the blood vessels formed in the scaffolds allowing 2D and 3D cell migration. Furthermore, the amount of bone formed in the scaffolds allowing 1D cell migration was 1.4-fold larger than that formed in the scaffolds allowing 2D and 3D cell migration. These are probably because the 1D space limited the direction of cell migration and prevented the branching of blood vessels, whereas 2D and 3D spaces provided the opportunity for random cell migration and blood vessel branching. Thus, scaffolds with 1D space are advantageous for inducing large and oriented blood vessels, resulting in a larger amount of bone formation.
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Affiliation(s)
- Koichiro Hayashi
- Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; (R.K.); (A.T.); (K.I.)
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Hayashi K, Kishida R, Tsuchiya A, Ishikawa K. Superiority of Triply Periodic Minimal Surface Gyroid Structure to Strut-Based Grid Structure in Both Strength and Bone Regeneration. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37433180 DOI: 10.1021/acsami.3c06263] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
The aging population has rapidly driven the demand for bone regeneration. The pore structure of a scaffold is a critical factor that affects its mechanical strength and bone regeneration. Triply periodic minimal surface gyroid structures similar to the trabecular bone structure are considered superior to strut-based lattice structures (e.g., grids) in terms of bone regeneration. However, at this stage, this is only a hypothesis and is not supported by evidence. In this study, we experimentally validated this hypothesis by comparing gyroid and grid scaffolds composed of carbonate apatite. The gyroid scaffolds possessed compressive strength approximately 1.6-fold higher than that of the grid scaffolds because the gyroid structure prevented stress concentration, whereas the grid structure could not. The porosity of gyroid scaffolds was higher than that of the grid scaffolds; however, porosity and compressive strength generally have a trade-off relationship. Moreover, the gyroid scaffolds formed more than twice the amount of bone as grid scaffolds in a critical-sized bone defect in rabbit femur condyles. This favorable bone regeneration using gyroid scaffolds was attributed to the high permeability (i.e., larger volume of macropores or porosity) and curvature profile of the gyroid structure. Thus, this study validated the conventional hypothesis using in vivo experiments and revealed factors that led to this hypothetical outcome. The findings of this study are expected to contribute to the development of scaffolds that can achieve early bone regeneration without sacrificing the mechanical strength.
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Affiliation(s)
- Koichiro Hayashi
- Department of Biomaterials, Faculty of Dental Science, Kyushu University 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Ryo Kishida
- Department of Biomaterials, Faculty of Dental Science, Kyushu University 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Akira Tsuchiya
- Department of Biomaterials, Faculty of Dental Science, Kyushu University 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kunio Ishikawa
- Department of Biomaterials, Faculty of Dental Science, Kyushu University 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Hayashi K, Yanagisawa T, Kishida R, Tsuchiya A, Ishikawa K. Gear-shaped carbonate apatite granules with a hexagonal macropore for rapid bone regeneration. Comput Struct Biotechnol J 2023; 21:2514-2523. [PMID: 37077175 PMCID: PMC10106487 DOI: 10.1016/j.csbj.2023.03.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/31/2023] [Accepted: 03/31/2023] [Indexed: 04/08/2023] Open
Abstract
Synthetic bone grafts are in high demand owing to increased age-related bone disorders in the global aging population. Here, we report fabrication of gear-shaped granules (G-GRNs) for rapid bone healing. G-GRNs possessed six protrusions and a hexagonal macropore in the granular center. These were composed of carbonate apatite, i.e., bone mineral, microspheres with ∼1-μm micropores in the spaces between the microspheres. G-GRNs formed new bone and blood vessels (both on the granular surface and within the macropores) 4 weeks after implantation in the rabbit femur defects. The formed bone structure was similar to that of cancellous bone. The bone percentage in the defect recovered to that in a normal rabbit femur at week-4 post-implantation, and the bone percentage remained constant for the following 8 weeks. Throughout the entire period, the bone percentage in the G-GRN-implanted group was ∼10% higher than that of the group implanted with conventional carbonate apatite granules. Furthermore, a portion of the G-GRNs resorbed at week-4, and resorption continued for the following 8 weeks. Thus, G-GRNs are involved in bone remodeling and are gradually replaced with new bone while maintaining a suitable bone level. These findings provide a basis for the design and fabrication of synthetic bone grafts for achieving rapid bone regeneration.
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Vezenkova A, Locs J. Sudoku of porous, injectable calcium phosphate cements – Path to osteoinductivity. Bioact Mater 2022; 17:109-124. [PMID: 35386461 PMCID: PMC8964990 DOI: 10.1016/j.bioactmat.2022.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 12/28/2021] [Accepted: 01/03/2022] [Indexed: 12/16/2022] Open
Abstract
With the increase of global population, people's life expectancy is growing as well. Humans tend to live more active lifestyles and, therefore, trauma generated large defects become more common. Instances of tumour resection or pathological conditions and complex orthopaedic issues occur more frequently increasing necessity for bone substitutes. Composition of calcium phosphate cements (CPCs) is comparable to the chemical structure of bone minerals. Their ability to self-set and resorb in vivo secures a variety of potential applications in bone regeneration. Despite the years-long research and several products already reaching the market, finding the right properties for calcium phosphate cement to be osteoinductive and both injectable and suitable for clinical use is still a sudoku. This article is focused on injectable, porous CPCs, reviewing the latest developments on the path toward finding osteoinductive material, which is suitable for injection. Phase separation is an essential factor to be improved to obtain injectable material; several methods have been proposed. Osteoinductive bone substitutes – possible solution for bad mechanical performance of CPCs. Osteoinductivity of CPC could be attained even without the addition of different supplements. Less complex composition of CPC – potentially reduced price of the final product and wider availability on the market.
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Hayashi K, Yanagisawa T, Kishida R, Ishikawa K. Effects of Scaffold Shape on Bone Regeneration: Tiny Shape Differences Affect the Entire System. ACS NANO 2022; 16:11755-11768. [PMID: 35833725 PMCID: PMC9413413 DOI: 10.1021/acsnano.2c03776] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Although studies on scaffolds for tissue generation have mainly focused on the chemical composition and pore structure, the effects of scaffold shape have been overlooked. Scaffold shape determines the scaffold surface area (SA) at the single-scaffold level (i.e., microscopic effects), although it also affects the amount of interscaffold space in the tissue defect at the whole-system level (i.e., macroscopic effects). To clarify these microscopic and macroscopic effects, this study reports the osteogenesis abilities of three types of carbonate apatite granular scaffolds with different shapes, namely, irregularly shaped dense granules (DGs) and two types of honeycomb granules (HCGs) with seven hexagonal channels (∼255 μm in length between opposite sides). The HCGs possessed either 12 protuberances (∼75 μm in length) or no protuberances. Protuberances increased the SA of each granule by 3.24 mm2 while also widening interscaffold spaces and increasing the space percentage in the defect by ∼7.6%. Interscaffold spaces were lower in DGs than HCGs. On DGs, new bone formed only on the surface, whereas on HCGs, bone simultaneously formed on the surface and in intrascaffold channels. Interestingly, HCGs without protuberances formed approximately 30% more new bone than those with protuberances. Thus, even tiny protuberances on the scaffold surface can affect the percentage of interscaffold space, thereby exerting dominant effects on osteogenesis. Our findings demonstrate that bone regeneration can be improved by considering macroscopic shape effects beyond the microscopic effects of the scaffold.
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Hayashi K, Yanagisawa T, Shimabukuro M, Kishida R, Ishikawa K. Granular honeycomb scaffolds composed of carbonate apatite for simultaneous intra- and inter-granular osteogenesis and angiogenesis. Mater Today Bio 2022; 14:100247. [PMID: 35378911 PMCID: PMC8976130 DOI: 10.1016/j.mtbio.2022.100247] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/14/2022] [Accepted: 03/22/2022] [Indexed: 02/08/2023] Open
Abstract
Granular porous calcium phosphate scaffolds are used for bone regeneration in dentistry. However, in conventional granules, the macropore interconnectivity is poor and has varying size. Herein, we developed a productive method for fabricating carbonate apatite honeycomb granules with uniformly sized macropores based on extrusion molding. Each honeycomb granule possesses three hexagonal macropores of ∼290 μm along its diagonal. Owing to these macropores, honeycomb granules simultaneously formed new and mature bone and blood vessels in both the interior and exterior of the granules at 4 weeks after implantation. The honeycomb granules are useful for achieving rapid osteogenesis and angiogenesis.
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Lei L, Wei Y, Wang Z, Han J, Sun J, Chen Y, Yang X, Wu Y, Chen L, Gou Z. Core–Shell Bioactive Ceramic Robocasting: Tuning Component Distribution Beneficial for Highly Efficient Alveolar Bone Regeneration and Repair. ACS Biomater Sci Eng 2020; 6:2376-2387. [PMID: 33455330 DOI: 10.1021/acsbiomaterials.0c00152] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Lihong Lei
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Yingming Wei
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Zhongxiu Wang
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Jiayin Han
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Jianwei Sun
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Yi Chen
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Xianyan Yang
- Bio-nanomaterials and Regenerative Medicine Research Division, Zhejiang-California International Nanosystem Institute, Zhejiang University, Hangzhou 310058, China
| | - Yanmin Wu
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Lili Chen
- Department of Periodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310008, China
| | - Zhongru Gou
- Bio-nanomaterials and Regenerative Medicine Research Division, Zhejiang-California International Nanosystem Institute, Zhejiang University, Hangzhou 310058, China
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