Additive manufacturing has enabled the customization of biomedical systems, including transplantable medical devices, to achieve mechanical biocompatibility. For bone implants, patient-specific bone models must be used to evaluate the mechanical properties of implant compression and subsidence. This study proposes a methodology for designing and fabricating bone models to evaluate patient-specific bone implants. The method involves three-dimensional printing of infill-varied structure, with alternating high-low-high infill density regions, which undergo sequential deformation from the surficial region during compression with an implant. Based on this deformation behavior, the relationship between infill density parameters and mechanical properties was confirmed with the tunability of mechanical properties involving stiffness and failure load. The infill-varied design was applied to the inner structures of artificial vertebra models based on computed tomography scans for cadaver specimens. By tailoring the infill density conditions, the stiffness and failure load were approximated to those of the natural vertebrae. Furthermore, this infill-varied artificial vertebra could be used to evaluate additive-manufactured patient-specific implants. The patient-specific implant had greater resistance to subsidence than the commercial implant, suggesting the feasibility of a biomimicking bone model. The bone-mimetic infill-varied structure could be used to evaluate patient-specific manufactured implants and could be applied to other bone engineering structures with optimized biomechanical properties.
{"title":"Additive-manufactured synthetic bone model with biomimicking tunable mechanical properties for evaluation of medical implants","authors":"Ju Chan Yuk, Kyoung Hyup Nam, Suk Hee Park","doi":"10.36922/ijb.1067","DOIUrl":"https://doi.org/10.36922/ijb.1067","url":null,"abstract":"Additive manufacturing has enabled the customization of biomedical systems, including transplantable medical devices, to achieve mechanical biocompatibility. For bone implants, patient-specific bone models must be used to evaluate the mechanical properties of implant compression and subsidence. This study proposes a methodology for designing and fabricating bone models to evaluate patient-specific bone implants. The method involves three-dimensional printing of infill-varied structure, with alternating high-low-high infill density regions, which undergo sequential deformation from the surficial region during compression with an implant. Based on this deformation behavior, the relationship between infill density parameters and mechanical properties was confirmed with the tunability of mechanical properties involving stiffness and failure load. The infill-varied design was applied to the inner structures of artificial vertebra models based on computed tomography scans for cadaver specimens. By tailoring the infill density conditions, the stiffness and failure load were approximated to those of the natural vertebrae. Furthermore, this infill-varied artificial vertebra could be used to evaluate additive-manufactured patient-specific implants. The patient-specific implant had greater resistance to subsidence than the commercial implant, suggesting the feasibility of a biomimicking bone model. The bone-mimetic infill-varied structure could be used to evaluate patient-specific manufactured implants and could be applied to other bone engineering structures with optimized biomechanical properties.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139439510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ying Lu, Xiaomin Zhang, Youjie Rong, Yannan Xu, Xiaohong Yao, Guobao Pang, Qinying Shi, Xiaobo Huang, Meiwen An, Jianbo Song
Boluses are a type of materials used to enhance skin dose during the treatment of superficial lesions. However, the current commercially available boluses cannot fully conform to irregular skin surfaces due to their uniform thickness, thereby compromising the efficacy of radiotherapy. Three-dimensional (3D) bioprinting boasts a huge potential in the creation of customized boluses, but the use of this technique is limited by shortcomings of the prevailing materials, such as their indirect printability and substance rigidity. As a potential substitute, hydrogels possessing a tensile modulus comparable to that of skin tissue are optimal candidates for customizing boluses. In this study, we developed a photocurable bioink for multifunctional boluses using digital light processing (DLP). Alginate, acrylamide, polyethylene glycol diacrylate, lithium phenyl-2,4,6-trimethylbenzoylphosphinate, and protocatechuic acid were synergistically combined to fabricate the bioink. The bolus printed using this bioink was endowed with enhanced toughness, superior adhesion, tissue equivalence, anti-dehydration and anti-bacterial properties, as well as excellent biocompatibility and radiation performance. In conclusion, the DLP-based 3D bioprinting of the proposed bioink can provide an avenue for obtaining personalized boluses in radiotherapy treatment of superficial tumors.
{"title":"3D bioprinting of adhesive, anti-bacterial alginate/polyacrylamide-based customized boluses using digital light processing for radiotherapy applications","authors":"Ying Lu, Xiaomin Zhang, Youjie Rong, Yannan Xu, Xiaohong Yao, Guobao Pang, Qinying Shi, Xiaobo Huang, Meiwen An, Jianbo Song","doi":"10.36922/ijb.1589","DOIUrl":"https://doi.org/10.36922/ijb.1589","url":null,"abstract":"Boluses are a type of materials used to enhance skin dose during the treatment of superficial lesions. However, the current commercially available boluses cannot fully conform to irregular skin surfaces due to their uniform thickness, thereby compromising the efficacy of radiotherapy. Three-dimensional (3D) bioprinting boasts a huge potential in the creation of customized boluses, but the use of this technique is limited by shortcomings of the prevailing materials, such as their indirect printability and substance rigidity. As a potential substitute, hydrogels possessing a tensile modulus comparable to that of skin tissue are optimal candidates for customizing boluses. In this study, we developed a photocurable bioink for multifunctional boluses using digital light processing (DLP). Alginate, acrylamide, polyethylene glycol diacrylate, lithium phenyl-2,4,6-trimethylbenzoylphosphinate, and protocatechuic acid were synergistically combined to fabricate the bioink. The bolus printed using this bioink was endowed with enhanced toughness, superior adhesion, tissue equivalence, anti-dehydration and anti-bacterial properties, as well as excellent biocompatibility and radiation performance. In conclusion, the DLP-based 3D bioprinting of the proposed bioink can provide an avenue for obtaining personalized boluses in radiotherapy treatment of superficial tumors.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139628350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stem cell differentiation has important implications for biomedical device design and tissue engineering. Recently, inherent material properties, including surface chemistry, stiffness, and topography, have been found to influence stem cell fate. Among these, surface topography is a key regulator of stem cells in contact with materials. The most important aspect of ideal bone tissue engineering is to control the organization of the bone extracellular matrix with fully differentiated osteoblasts. Here, we found that laser powder bed fusion (PBF-LB)-fabricated grooved surface inspired by the microstructure of bone, which induced human mesenchymal stem cell (hMSC) differentiation into the osteogenic lineage without any differentiation supplements. The periodic grooved structure was fabricated by PBF-LB which induced cell elongation facilitated by cytoskeletal tension along the grooves. This resulted in the upregulation of osteogenesis via Runx2 expression. The aligned hMSCs successfully differentiated into osteoblasts and further organized the bone mimetic-oriented extracellular matrix microstructure. Our results indicate that metal additive manufacturing technology has a great advantage in controlling stem cell fate into the osteogenic lineage, and in the construction of bone-mimetic microstructural organization. Our findings on material-induced stem cell differentiation under standard cell culture conditions open new avenues for the development of medical devices that realize the desired tissue regeneration mediated by regulated stem cell functions.
{"title":"PBF-LB fabrication of microgrooves for induction of osteogenic differentiation of human mesenchymal stem cells","authors":"Aira Matsugaki, Tadaaki Matsuzaka, Toko Mori, Mitsuka Saito, Kazuma Funaoku, Riku Yamano, O. Gokcekaya, Ryosuke Ozasa, Takayoshi Nakano","doi":"10.36922/ijb.1425","DOIUrl":"https://doi.org/10.36922/ijb.1425","url":null,"abstract":"Stem cell differentiation has important implications for biomedical device design and tissue engineering. Recently, inherent material properties, including surface chemistry, stiffness, and topography, have been found to influence stem cell fate. Among these, surface topography is a key regulator of stem cells in contact with materials. The most important aspect of ideal bone tissue engineering is to control the organization of the bone extracellular matrix with fully differentiated osteoblasts. Here, we found that laser powder bed fusion (PBF-LB)-fabricated grooved surface inspired by the microstructure of bone, which induced human mesenchymal stem cell (hMSC) differentiation into the osteogenic lineage without any differentiation supplements. The periodic grooved structure was fabricated by PBF-LB which induced cell elongation facilitated by cytoskeletal tension along the grooves. This resulted in the upregulation of osteogenesis via Runx2 expression. The aligned hMSCs successfully differentiated into osteoblasts and further organized the bone mimetic-oriented extracellular matrix microstructure. Our results indicate that metal additive manufacturing technology has a great advantage in controlling stem cell fate into the osteogenic lineage, and in the construction of bone-mimetic microstructural organization. Our findings on material-induced stem cell differentiation under standard cell culture conditions open new avenues for the development of medical devices that realize the desired tissue regeneration mediated by regulated stem cell functions.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fan Liu, Chaohan Wu, Xinhui Wang, Rong-Zuo Guo, Tianhua Dong, Tao Zhang
The aim of this study was to investigate the use of three-dimensional (3D) printing technology to create a biodegradable scaffold loaded with WNT5A protein and assess its impact on chronic tibial osteomyelitis with bone defects (CTO&BD), focusing on osteoblast differentiation and angiogenesis. We extracted RNA from peripheral blood of healthy individuals and CTO&BD patients for sequencing, followed by differential expression and functional enrichment analysis. Network analysis was performed to identify core genes associated with CTO&BD and construct a protein–protein interaction network. Using Masquelet technique, we fabricated a 3D-printed biodegradable scaffold (G40T60@WNT5A) and conducted various experiments, including rheological testing, printability evaluation, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy analysis, as well as mechanical and degradation performance assessments. In in vivo experiments, we observed the formation of induced membranes in a CTO&BD rat model implanted with the scaffold. In vitro experiments involved the assessment of scaffold toxicity on rat bone marrow mesenchymal stem cells and umbilical vein endothelial cells, as well as the influence on osteoblast differentiation and angiogenesis. Molecular biology techniques were used to analyze gene and protein expression levels. We discovered for the first time that WNT5A may play a crucial role in CTO&BD. The biodegradable scaffold prepared by 3D printing (G40T60@WNT5A) exhibited excellent biocompatibility in vitro. This scaffold significantly promoted the formation of induced membranes in CTO&BD rats and further enhanced osteoblast differentiation and angiogenesis. In conclusion, this study utilized innovative 3D printing technology to fabricate the G40T60@WNT5A scaffold, confirming its potential application in the treatment of CTO&BD, particularly in promoting osteoblast differentiation and angiogenesis. This research provides new methods and theoretical support for the treatment of bone defects.
{"title":"Building a degradable scaffold with 3D printing using Masquelet technique to promote osteoblast differentiation and angiogenesis in chronic tibial osteomyelitis with bone defects","authors":"Fan Liu, Chaohan Wu, Xinhui Wang, Rong-Zuo Guo, Tianhua Dong, Tao Zhang","doi":"10.36922/ijb.1461","DOIUrl":"https://doi.org/10.36922/ijb.1461","url":null,"abstract":"The aim of this study was to investigate the use of three-dimensional (3D) printing technology to create a biodegradable scaffold loaded with WNT5A protein and assess its impact on chronic tibial osteomyelitis with bone defects (CTO&BD), focusing on osteoblast differentiation and angiogenesis. We extracted RNA from peripheral blood of healthy individuals and CTO&BD patients for sequencing, followed by differential expression and functional enrichment analysis. Network analysis was performed to identify core genes associated with CTO&BD and construct a protein–protein interaction network. Using Masquelet technique, we fabricated a 3D-printed biodegradable scaffold (G40T60@WNT5A) and conducted various experiments, including rheological testing, printability evaluation, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy analysis, as well as mechanical and degradation performance assessments. In in vivo experiments, we observed the formation of induced membranes in a CTO&BD rat model implanted with the scaffold. In vitro experiments involved the assessment of scaffold toxicity on rat bone marrow mesenchymal stem cells and umbilical vein endothelial cells, as well as the influence on osteoblast differentiation and angiogenesis. Molecular biology techniques were used to analyze gene and protein expression levels. We discovered for the first time that WNT5A may play a crucial role in CTO&BD. The biodegradable scaffold prepared by 3D printing (G40T60@WNT5A) exhibited excellent biocompatibility in vitro. This scaffold significantly promoted the formation of induced membranes in CTO&BD rats and further enhanced osteoblast differentiation and angiogenesis. In conclusion, this study utilized innovative 3D printing technology to fabricate the G40T60@WNT5A scaffold, confirming its potential application in the treatment of CTO&BD, particularly in promoting osteoblast differentiation and angiogenesis. This research provides new methods and theoretical support for the treatment of bone defects.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Li Zhang, Haofan Liu, Linghong Guo, Xuebing Jiang, Siyi Wang, Run Tian, Yiting Huang, Xian Jiang, Maling Gou
Skin photodamage is a common disease that can cause various skin problems, and vitamin C is frequently used as an antioxidant to protect the skin from photodamage. However, vitamin C is a charged and hydrophilic molecule, which decreases skin permeability. In this study, we developed a type of microneedle particles (MNPs) to enhance topical vitamin C delivery. The MNPs are millimeter-sized particles with micron-sized needle-like structures that can be rapidly and accurately fabricated through a digital light processing (DLP)-based micro-printing process. The mechanical properties of these MNPs are reliable for forming micropores across the stratum corneum in a painless manner. Following a topical application to the dorsal skin of mice, the MNPs increased the permeability of medications. The effectiveness of vitamin C in mitigating skin photodamage is significantly improved. In conclusion, this study presents micro-printing of MNPs for transdermal vitamin C delivery, which has potential applications in future treatment of skin photodamage.
皮肤光损伤是一种常见疾病，可导致各种皮肤问题，维生素 C 经常被用作抗氧化剂，以保护皮肤免受光损伤。然而，维生素 C 是一种带电的亲水分子，会降低皮肤的渗透性。在这项研究中，我们开发了一种微针颗粒（MNPs）来增强维生素 C 的局部输送。MNPs 是一种具有微米级针状结构的毫米级颗粒，可通过基于数字光处理（DLP）的微打印工艺快速、准确地制造出来。这些 MNPs 的机械性能可靠，能以无痛方式在角质层形成微孔。在小鼠背侧皮肤局部使用后，MNPs 增加了药物的渗透性。维生素 C 在减轻皮肤光损伤方面的效果显著提高。总之，本研究介绍了用于透皮维生素 C 给药的 MNPs 微印刷技术，它在未来治疗皮肤光损伤方面具有潜在的应用价值。
{"title":"Improving the transdermal delivery of vitamin C by 3D-printed microneedle particles for alleviating skin photodamage","authors":"Li Zhang, Haofan Liu, Linghong Guo, Xuebing Jiang, Siyi Wang, Run Tian, Yiting Huang, Xian Jiang, Maling Gou","doi":"10.36922/ijb.1285","DOIUrl":"https://doi.org/10.36922/ijb.1285","url":null,"abstract":"Skin photodamage is a common disease that can cause various skin problems, and vitamin C is frequently used as an antioxidant to protect the skin from photodamage. However, vitamin C is a charged and hydrophilic molecule, which decreases skin permeability. In this study, we developed a type of microneedle particles (MNPs) to enhance topical vitamin C delivery. The MNPs are millimeter-sized particles with micron-sized needle-like structures that can be rapidly and accurately fabricated through a digital light processing (DLP)-based micro-printing process. The mechanical properties of these MNPs are reliable for forming micropores across the stratum corneum in a painless manner. Following a topical application to the dorsal skin of mice, the MNPs increased the permeability of medications. The effectiveness of vitamin C in mitigating skin photodamage is significantly improved. In conclusion, this study presents micro-printing of MNPs for transdermal vitamin C delivery, which has potential applications in future treatment of skin photodamage.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139628958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microfluidics is a facile platform that manipulates fluids for the production of droplets, particles, and microcapsules. However, the application of microfluidics is limited to the manipulation of the droplet position and the presence of a continuous oil phase, which needs to be removed for biomedical applications. Here, we used air as the continuous phase and developed a facile method for droplet generation and patterning by air-focused microfluidic three-dimensional (3D) droplet printing (AFMDP). By tuning the viscous drag of a focused air flow, monodisperse droplets with tunable size were generated in a microfluidic device, and droplet patterns were designed by combining the control system of the 3D printer. When using droplets as templates, hydrogel particles were prepared by AFMDP and crosslinked in a CaCl2 bath. These hydrogel particles were proven to be good carriers for the cell culture, controlled release, and immune therapy using chimeric antigen receptor (CAR) T cells. Cell viability and activity results confirmed that encapsulation of CAR-T cells in hydrogel particles did not compromise their cell activity and functionality but facilitated their manipulation and cell culture. Therefore, the AFMDP system provided a versatile platform for the design of droplets, particles, and microcapsules for biomedical applications.
{"title":"Controlled preparation of droplets for cell encapsulation by air-focused microfluidic bioprinting ","authors":"Chenjing Yang, Wei Wu, Yang 1†, Shuxing Lao, Shikai Zhang, Jianghui Tang, Xingqun Pu, Xingyu Lu, Fangfu Ye, Peng Zhao, Dong Chen","doi":"10.36922/ijb.1102","DOIUrl":"https://doi.org/10.36922/ijb.1102","url":null,"abstract":"Microfluidics is a facile platform that manipulates fluids for the production of droplets, particles, and microcapsules. However, the application of microfluidics is limited to the manipulation of the droplet position and the presence of a continuous oil phase, which needs to be removed for biomedical applications. Here, we used air as the continuous phase and developed a facile method for droplet generation and patterning by air-focused microfluidic three-dimensional (3D) droplet printing (AFMDP). By tuning the viscous drag of a focused air flow, monodisperse droplets with tunable size were generated in a microfluidic device, and droplet patterns were designed by combining the control system of the 3D printer. When using droplets as templates, hydrogel particles were prepared by AFMDP and crosslinked in a CaCl2 bath. These hydrogel particles were proven to be good carriers for the cell culture, controlled release, and immune therapy using chimeric antigen receptor (CAR) T cells. Cell viability and activity results confirmed that encapsulation of CAR-T cells in hydrogel particles did not compromise their cell activity and functionality but facilitated their manipulation and cell culture. Therefore, the AFMDP system provided a versatile platform for the design of droplets, particles, and microcapsules for biomedical applications.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139628962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, a series of new gradient porous scaffolds were innovatively designed via a dual-unit continuous transition connection strategy based on the minimal surface structures (primitive [P], diamond [D], and gyroid [G]). The scaffolds were successfully prepared through selective laser melting technology. The results showed that the dual-unit continuous transition connection strategy significantly improved the mechanical properties of the connected scaffolds. The compression strength of the scaffolds was found to be (P-G)>(P-D)>(G-P)>(G-D)>(D-G)>(D-P), with the P-G structure exhibiting a compression strength of 167.7 MPa and an elastic modulus of 3.3 GPa. The mechanical properties of the porous scaffolds were primarily influenced by the outer unit type, the connection condition between different units, the unit size, and the porosity. Scaffolds with the outer P unit demonstrated better mechanical properties due to the higher mechanical strength of the P structure. The connection performance between different units varied, with P and G units forming a good continuous transition connection, while the connection performance between P and D units was the weakest. The dual-unit continuous transition connection strategy offers a promising approach to optimize the connection performance of different units, providing new insights into the design of medical porous scaffolds.
本研究基于最小表面结构（原始结构[P]、菱形结构[D]和陀螺结构[G]），通过双单元连续过渡连接策略，创新性地设计了一系列新型梯度多孔支架。通过选择性激光熔融技术成功制备了支架。结果表明，双单元连续过渡连接策略显著提高了连接支架的力学性能。支架的压缩强度依次为（P-G）>（P-D）>（G-P）>（G-D）>（D-G）>（D-P），其中 P-G 结构的压缩强度为 167.7 MPa，弹性模量为 3.3 GPa。多孔支架的力学性能主要受外单元类型、不同单元之间的连接条件、单元尺寸和孔隙率的影响。由于 P 结构的机械强度较高，外层为 P 单元的支架具有更好的机械性能。不同单元之间的连接性能各不相同，P 单元和 G 单元形成了良好的连续过渡连接，而 P 单元和 D 单元之间的连接性能最弱。双单元连续过渡连接策略为优化不同单元的连接性能提供了一种可行的方法，为医用多孔支架的设计提供了新的思路。
{"title":"Design of biomedical gradient porous scaffold via a minimal surface dual-unit continuous transition connection strategy","authors":"Yuting Lv, Zheng Shi, Binghao Wang, Miao Luo, Ouyang Xing, Jia Liu, Hao Dong, Yanlei Sun, Liqiang Wang","doi":"10.36922/ijb.1263","DOIUrl":"https://doi.org/10.36922/ijb.1263","url":null,"abstract":"In this work, a series of new gradient porous scaffolds were innovatively designed via a dual-unit continuous transition connection strategy based on the minimal surface structures (primitive [P], diamond [D], and gyroid [G]). The scaffolds were successfully prepared through selective laser melting technology. The results showed that the dual-unit continuous transition connection strategy significantly improved the mechanical properties of the connected scaffolds. The compression strength of the scaffolds was found to be (P-G)>(P-D)>(G-P)>(G-D)>(D-G)>(D-P), with the P-G structure exhibiting a compression strength of 167.7 MPa and an elastic modulus of 3.3 GPa. The mechanical properties of the porous scaffolds were primarily influenced by the outer unit type, the connection condition between different units, the unit size, and the porosity. Scaffolds with the outer P unit demonstrated better mechanical properties due to the higher mechanical strength of the P structure. The connection performance between different units varied, with P and G units forming a good continuous transition connection, while the connection performance between P and D units was the weakest. The dual-unit continuous transition connection strategy offers a promising approach to optimize the connection performance of different units, providing new insights into the design of medical porous scaffolds.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139448082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Regeneration of large-sized cartilage injury is a challenging endeavor. In vitro bioprinting for cartilage repair has several drawbacks, such as the tedious process of material preparation, potential contamination, and the mismatch between implant and defect. This study aimed to investigate the application of in situ bioprinting in cartilage repair using a parallel manipulator. In particular, the material extrusion rate and printing speed were adjusted to obtain the suitable forming parameters in a custom-made parallel manipulator. Cell experiments were conducted to determine the biocompatibility. Finally, a rabbit cartilage defect model was used to evaluate the feasibility of in situ bioprinting combined with machine vision. The results showed that to achieve optimum printing using the custom-made three-dimensional printer, 400–560 mm/min should be set as the standard printing speed, with an extrusion multiplier of 0.09–0.10. Cartilage defects can be precisely and easily segmented using a bimodal method with a 2% deviation error. In vitro experiments revealed that the utilized materials are highly biocompatible. Furthermore, according to the results from in vivo experiments, in situ bioprinting lends itself useful in the repair of cartilage defects. The overall results confirmed the feasibility of applying a parallel manipulator in in situ bioprinting for cartilage repair. Additional optimizations of the proposed approach are warranted prior to translation into clinical applications in the future.
{"title":"In situ bioprinting for cartilage repair using a parallel manipulator","authors":"Hao-Yang Lei, You-Rong Chen, Zi-Bin Liu, Yi-Nong Li, Bing-Bing Xu, Chang-Hui Song, Jia-Kuo Yu","doi":"10.36922/ijb.1437","DOIUrl":"https://doi.org/10.36922/ijb.1437","url":null,"abstract":"Regeneration of large-sized cartilage injury is a challenging endeavor. In vitro bioprinting for cartilage repair has several drawbacks, such as the tedious process of material preparation, potential contamination, and the mismatch between implant and defect. This study aimed to investigate the application of in situ bioprinting in cartilage repair using a parallel manipulator. In particular, the material extrusion rate and printing speed were adjusted to obtain the suitable forming parameters in a custom-made parallel manipulator. Cell experiments were conducted to determine the biocompatibility. Finally, a rabbit cartilage defect model was used to evaluate the feasibility of in situ bioprinting combined with machine vision. The results showed that to achieve optimum printing using the custom-made three-dimensional printer, 400–560 mm/min should be set as the standard printing speed, with an extrusion multiplier of 0.09–0.10. Cartilage defects can be precisely and easily segmented using a bimodal method with a 2% deviation error. In vitro experiments revealed that the utilized materials are highly biocompatible. Furthermore, according to the results from in vivo experiments, in situ bioprinting lends itself useful in the repair of cartilage defects. The overall results confirmed the feasibility of applying a parallel manipulator in in situ bioprinting for cartilage repair. Additional optimizations of the proposed approach are warranted prior to translation into clinical applications in the future.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139628666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Porous structure is an efficient tool for optimizing the elastic modulus and osseointegration properties of titanium alloy materials. However, the investigations on pore shape remain scarce. In this study, we created porous Ti6Al4V scaffolds with a pore size of 600 μm but different lattices (cubic pentagon, diamond, cuboctahedron). The mechanical and biological properties of the scaffolds were investigated in static simulation analysis, in vitro mechanical compression test, computational fluid dynamics, as well as cell and animal experiments. The results demonstrated that the calculated yield strength difference between the three Ti6Al4V porous scaffolds was negligible, at approximately 140 MPa, allowing them to match the strength requirements of human bones. The diamond scaffold has the lowest calculated elastic modulus (11.6 GPa), which is conducive for preventing stress shielding. The shear stress was largely concentrated in the diamond scaffold, and the stress range of 120–140 MPa accounted for the greatest share. The mouse MC3T3-E1 cells were found to attach to all three scaffolds, with the diamond scaffold displaying a higher degree of cell adherence. There was more proliferating cells on the diamond and cubic pentagon scaffolds than on the cuboctahedron scaffolds (P < 0.05). The diamond scaffold exhibited the highest alkaline phosphatase activity and calcium salt accumulation in cell differentiation tests. Besides, the expression of osteogenic genes on the diamond scaffold was higher than that on the cuboctahedron scaffold, the cubic pentagon scaffold displaying the lowest expression. The in vivo studies revealed that all three scaffolds fused well with the surrounding bone and that there was no loosening or movement of the prosthesis. Micro-computed tomography, corroborated by the staining results of hard tissues, revealed that the level of new bone formation was the highest in the diamond scaffold, followed by the cuboctahedron scaffold (P < 0.05). Taken together, the diamond scaffold is comparatively better at optimizing the elastic modulus and osseointegration properties of titanium alloy materials, and thus is a preferred choice for porous design.
{"title":"Effect of lattice type on biomechanical and osseointegration properties of 3D-printed porous Ti6Al4V scaffolds","authors":"Jiantao Liu, Kao Wang, Runqing Wang, Zhanhai Yin, Xiaoling Zhou, Aofei Xu, Xiwei Zhang, Yiming Li, Ruiyan Wang, Shuyuan Zhang, Jun Cheng, Weiguo Bian, Jia Li, Zhiwei Ren, Mengyuan Sun, Yin Yang, Dezhi Wang, Jing Ren","doi":"10.36922/ijb.1698","DOIUrl":"https://doi.org/10.36922/ijb.1698","url":null,"abstract":"Porous structure is an efficient tool for optimizing the elastic modulus and osseointegration properties of titanium alloy materials. However, the investigations on pore shape remain scarce. In this study, we created porous Ti6Al4V scaffolds with a pore size of 600 μm but different lattices (cubic pentagon, diamond, cuboctahedron). The mechanical and biological properties of the scaffolds were investigated in static simulation analysis, in vitro mechanical compression test, computational fluid dynamics, as well as cell and animal experiments. The results demonstrated that the calculated yield strength difference between the three Ti6Al4V porous scaffolds was negligible, at approximately 140 MPa, allowing them to match the strength requirements of human bones. The diamond scaffold has the lowest calculated elastic modulus (11.6 GPa), which is conducive for preventing stress shielding. The shear stress was largely concentrated in the diamond scaffold, and the stress range of 120–140 MPa accounted for the greatest share. The mouse MC3T3-E1 cells were found to attach to all three scaffolds, with the diamond scaffold displaying a higher degree of cell adherence. There was more proliferating cells on the diamond and cubic pentagon scaffolds than on the cuboctahedron scaffolds (P < 0.05). The diamond scaffold exhibited the highest alkaline phosphatase activity and calcium salt accumulation in cell differentiation tests. Besides, the expression of osteogenic genes on the diamond scaffold was higher than that on the cuboctahedron scaffold, the cubic pentagon scaffold displaying the lowest expression. The in vivo studies revealed that all three scaffolds fused well with the surrounding bone and that there was no loosening or movement of the prosthesis. Micro-computed tomography, corroborated by the staining results of hard tissues, revealed that the level of new bone formation was the highest in the diamond scaffold, followed by the cuboctahedron scaffold (P < 0.05). Taken together, the diamond scaffold is comparatively better at optimizing the elastic modulus and osseointegration properties of titanium alloy materials, and thus is a preferred choice for porous design.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139535611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Kocich, L. Kuncická, Marek Benč, Adam Weiser, Gergely Németh
Additive manufacturing (AM) is gaining increasing popularity in various fields, including biomedical engineering. Although AM enables fabrication of tailored components with complex geometries, the manufactured parts typically feature several internal issues, such as unpredictable distribution of residual stress and printing defects. However, these issues can be reduced or eliminated by post-processing via thermomechanical treatment. The study investigated the effects of combinations of AM and post-processing by the intensive plastic deformation method of rotary swaging (variable swaging ratios) on microstructures, residual stress, and corrosion behaviors of AISI 316L stainless steel workpieces; the corrosion tests were performed in an ionized simulated body fluid. The results showed that the gradual swaging process favorably refined the grains and homogenized the grain size. The imposed swaging ratio also directly influenced the development of substructure and dislocations density. A high density of dislocations positively affected the corrosion resistance, whereas annihilation of dislocations and formation of subgrains had a negative effect on the corrosion behavior. The first few swaging passes homogenized the distribution of residual stress within the workpiece and acted toward imparting a predominantly compressive stress state, which also favorably influenced the corrosion behavior. Lastly, the presence of the {111}||swaging direction texture fiber (of a high intensity) increased the resistance to pitting corrosion. Overall, the most favorable corrosion behavior was acquired for the AM sample subjected to the swaging ratio of 0.8, exhibiting a strong fiber texture and a high density of dislocations.
快速成型制造（AM）在包括生物医学工程在内的各个领域越来越受欢迎。虽然增材制造可以制造出具有复杂几何形状的定制部件，但制造出的部件通常会出现一些内部问题，如不可预知的残余应力分布和打印缺陷。不过，这些问题可以通过热机械处理的后处理方法来减少或消除。该研究调查了 AM 与旋转锻造（可变锻造比）强化塑性变形方法后处理的组合对 AISI 316L 不锈钢工件的微观结构、残余应力和腐蚀行为的影响；腐蚀测试在离子化模拟体液中进行。结果表明，渐进式锻造过程有利于细化晶粒和均匀晶粒尺寸。所施加的锻造比率也直接影响了亚结构和位错密度的发展。位错密度高会对耐腐蚀性产生积极影响，而位错湮灭和亚晶粒的形成则会对腐蚀行为产生消极影响。前几道锻造工序使工件内部的残余应力分布均匀化，并形成了以压应力为主的应力状态，这也对腐蚀行为产生了有利影响。最后，{111}|||浇铸方向纹理纤维（高强度）的存在提高了抗点蚀能力。总体而言，采用 0.8 拉伸比的 AM 样品具有最理想的腐蚀性能，表现出较强的纤维纹理和较高的位错密度。
{"title":"Corrosion behavior of selective laser melting-manufactured bio-applicable 316L stainless steel in ionized simulated body fluid","authors":"R. Kocich, L. Kuncická, Marek Benč, Adam Weiser, Gergely Németh","doi":"10.36922/ijb.1416","DOIUrl":"https://doi.org/10.36922/ijb.1416","url":null,"abstract":"Additive manufacturing (AM) is gaining increasing popularity in various fields, including biomedical engineering. Although AM enables fabrication of tailored components with complex geometries, the manufactured parts typically feature several internal issues, such as unpredictable distribution of residual stress and printing defects. However, these issues can be reduced or eliminated by post-processing via thermomechanical treatment. The study investigated the effects of combinations of AM and post-processing by the intensive plastic deformation method of rotary swaging (variable swaging ratios) on microstructures, residual stress, and corrosion behaviors of AISI 316L stainless steel workpieces; the corrosion tests were performed in an ionized simulated body fluid. The results showed that the gradual swaging process favorably refined the grains and homogenized the grain size. The imposed swaging ratio also directly influenced the development of substructure and dislocations density. A high density of dislocations positively affected the corrosion resistance, whereas annihilation of dislocations and formation of subgrains had a negative effect on the corrosion behavior. The first few swaging passes homogenized the distribution of residual stress within the workpiece and acted toward imparting a predominantly compressive stress state, which also favorably influenced the corrosion behavior. Lastly, the presence of the {111}||swaging direction texture fiber (of a high intensity) increased the resistance to pitting corrosion. Overall, the most favorable corrosion behavior was acquired for the AM sample subjected to the swaging ratio of 0.8, exhibiting a strong fiber texture and a high density of dislocations.","PeriodicalId":48522,"journal":{"name":"International Journal of Bioprinting","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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