51
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Boschetto F, Marin E, Ohgitani E, Adachi T, Zanocco M, Horiguchi S, Zhu W, McEntire BJ, Mazda O, Bal BS, Pezzotti G. Surface functionalization of PEEK with silicon nitride. Biomed Mater 2020; 16. [PMID: 32906100 DOI: 10.1088/1748-605x/abb6b1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022]
Abstract
Surface roughness, bioactivity, and antibacterial properties are desirable in skeletal implants. We hot-pressed a mix of particulate sodium chloride (NaCl) salt and silicon nitride (β-Si3N4) onto the surface of bulk PEEK. NaCl grains were removed by leaching in water, resulting in a porous PEEK surface embedded with ~15 vol.% β-Si3N4 particles. This functionalized surface showed the osteogenic and antibacterial properties previously reported in bulk silicon nitride implants. Surface enhancement of PEEK with β-Si3N4 could improve the performance of spinal fusion cages, by facilitating arthrodesis and resisting bacteria.
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Affiliation(s)
| | - Elia Marin
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, JAPAN
| | | | | | - Matteo Zanocco
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, JAPAN
| | | | - Wenliang Zhu
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Research Institute for Nanoscience, Sakyo-ku, Matsugasaki, 606-8585 Kyoto, Kyoto, JAPAN
| | | | - Osam Mazda
- Kyoto Prefectural University of Medicine, Kyoto, JAPAN
| | - B Sonny Bal
- SINTX Technologies, Salt Lake City, UNITED STATES
| | - Giuseppe Pezzotti
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto, Kyoto, JAPAN
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52
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Huo S, Meng X, Zhang S, Yue B, Zhao Y, Long T, Nie B, Wang Y. Hydrofluoric acid and nitric acid cotreatment for biofunctionalization of polyetheretherketone in M2 macrophage polarization and osteogenesis. J Biomed Mater Res A 2020; 109:879-892. [PMID: 32780520 DOI: 10.1002/jbm.a.37079] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/22/2020] [Accepted: 07/28/2020] [Indexed: 12/14/2022]
Abstract
Due to its excellent mechanical and low-friction properties, polyetheretherketone (PEEK) has been widely investigated for use in orthopedic applications over the past decade. However, the bioinertness and poor osteogenic properties of PEEK have hampered its clinical application. In this study, the surface of PEEK was modified by co-treatment with hydrofluoric acid and nitric acid (AFN). The microstructures of the modified PEEK surfaces were investigated using scanning electron microscopy. The water contact angles of the surfaces were also measured. To evaluate their cytocompatibility, PEEK samples were used as substrates to culture rat bone mesenchymal stem cells, and cell adhesion, viability, and expression of specific marker genes were measured. Treatment of PEEK with AFN (PEEK-AFN) was found to enable better osteoblast adhesion, spreading, and proliferation; the activity of alkaline phosphatase (an early osteogenic differentiation marker) was also found to be enhanced post-treatment. Furthermore, PEEK-AFN was able to modulate macrophage polarization and down regulated the expression of proinflammatory factors via inhibiting the NF-κB pathway. Thus, treatment of PEEK with AFN could promote M2 polarization of the macrophages and stimulate the differentiation of osteoblasts. These results provide valuable information that could facilitate the use of PEEK-based composites as bone implant materials.
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Affiliation(s)
- Shicheng Huo
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
| | - Xiangchao Meng
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
| | - Shutao Zhang
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
| | - Bing Yue
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
| | - Yaochao Zhao
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
| | - Teng Long
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
| | - Bin'en Nie
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
| | - You Wang
- Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, China
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Zanjanijam AR, Major I, Lyons JG, Lafont U, Devine DM. Fused Filament Fabrication of PEEK: A Review of Process-Structure-Property Relationships. Polymers (Basel) 2020; 12:E1665. [PMID: 32726994 PMCID: PMC7465918 DOI: 10.3390/polym12081665] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/16/2020] [Accepted: 07/18/2020] [Indexed: 12/15/2022] Open
Abstract
Poly (ether ether ketone) (PEEK) is a high-performance engineering thermoplastic polymer with potential for use in a variety of metal replacement applications due to its high strength to weight ratio. This combination of properties makes it an ideal material for use in the production of bespoke replacement parts for out-of-earth manufacturing purposes, in particular on the International Space Station (ISS). Additive manufacturing (AM) may be employed for the production of these parts, as it has enabled new fabrication pathways for articles with complex design considerations. However, AM of PEEK via fused filament fabrication (FFF) encounters significant challenges, mostly stemming from the semi crystalline nature of PEEK and its associated high melting temperature. This makes PEEK highly susceptible to changes in processing conditions which leads to a large reported variation in the literature on the final performance of PEEK. This has limited the adaption of FFF printing of PEEK in space applications where quality assurance and reproducibility are paramount. In recent years, several research studies have examined the effect of printing parameters on the performance of the 3D-printed PEEK parts. The aim of the current review is to provide comprehensive information in relation to the process-structure-property relationships in FFF 3D-printing of PEEK to provide a clear baseline to the research community and assesses its potential for space applications, including out-of-earth manufacturing.
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Affiliation(s)
- Ali Reza Zanjanijam
- Materials Research Institute, Athlone Institute of Technology, N37 HD68 Athlone, Ireland
| | - Ian Major
- Materials Research Institute, Athlone Institute of Technology, N37 HD68 Athlone, Ireland
| | - John G Lyons
- Faculty of Engineering and Informatics, Athlone Institute of Technology, N37 HD68 Athlone, Ireland
| | - Ugo Lafont
- European Space Technology and Research Centre, European Space Agency, Keplerlaan 1, 2201 AZ Noordwijk, The Netherland
| | - Declan M Devine
- Materials Research Institute, Athlone Institute of Technology, N37 HD68 Athlone, Ireland
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da Cruz MB, Marques JF, Peñarrieta-Juanito GM, Costa M, Souza JCM, Magini RS, Miranda G, Silva FS, Caramês JMM, da Mata ADSP. Bioactive-Enhanced Polyetheretherketone Dental Implant Materials: Mechanical Characterization and Cellular Responses. J ORAL IMPLANTOL 2020; 47:9-17. [DOI: 10.1563/aaid-joi-d-19-00172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to characterize the mechanical properties of a bioactive-modified polyetheretherketone (PEEK) manufacturing approach for dental implants and to compare the in vitro biological behavior with titanium alloy (Ti6Al4V) as the reference. PEEK, PEEK with 5% hydroxyapatite (HA), PEEK with 5% beta-tricalcium phosphate (βTCP), and Ti6Al4V discs were produced using hot pressing technology to create a functionally graded material (FGM). Surface roughness values (Ra, Rz), water contact angle, shear bond strength, and Vickers hardness tests were performed. Human osteoblasts and gingival fibroblasts bioactivity was evaluated by a resazurin-based method, alkaline phosphatase activity (ALP), and confocal laser scanning microscopy (CLSM) images of fluorescent-stained fibroblasts. Morphology and cellular adhesion were confirmed using field emission gun-scanning electron microscopy (FEG-SEM). Group comparisons were tested using analysis of variance (Tukey post hoc test), α = .05. All groups presented similar roughness values (P > .05). Ti6Al4V group was found to have the highest contact angle (P < .05). Shear bond strength and Vickers hardness of different PEEK materials were similar (P > .05); however, the mean values in the Ti6Al4V group were significantly higher when compared with those of the other groups (P < .05). Cell viability and proliferation of osteoblast and fibroblast cells were higher in the PEEK group (P < .05). PEEK-βTCP showed the highest significant ALP activity over time (P < .05 at 14 days of culture). An enhanced bone and soft-tissue cell behavior on pure PEEK was obtained to the gold standard (Ti6Al4V) with equivalent roughness. The results substantiate the potential role of chemical composition rather than physical properties of materials in biological responses. The addition of 5% HA or βTCP by FGM did not enhance PEEK mechanical properties or periodontal cell behavior.
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Affiliation(s)
- Mariana Brito da Cruz
- Oral Biology and Biochemistry Research Group, LIBPhys, Faculty of Dental Medicine, Universidade de Lisboa, Lisboa, Portugal
| | - Joana Faria Marques
- Oral Biology and Biochemistry Research Group, LIBPhys, Faculty of Dental Medicine, Universidade de Lisboa, Lisboa, Portugal
| | - Gabriella M. Peñarrieta-Juanito
- Center for Research on Dental Implants, Postgraduate Program in Dentistry, School of Dentistry, Federal University of Santa Catarina, Florianópolis/SC, Brazil
| | - Mafalda Costa
- Center for Microelectromechanical Systems, Department of Mechanical Engineering, University of Minho, Guimarães, Portugal
| | - Júlio C. M. Souza
- Center for Research on Dental Implants, Postgraduate Program in Dentistry, School of Dentistry, Federal University of Santa Catarina, Florianópolis/SC, Brazil
| | - Ricardo S. Magini
- Center for Research on Dental Implants, Postgraduate Program in Dentistry, School of Dentistry, Federal University of Santa Catarina, Florianópolis/SC, Brazil
| | - Georgina Miranda
- Center for Microelectromechanical Systems, Department of Mechanical Engineering, University of Minho, Guimarães, Portugal
| | - Filipe Samuel Silva
- Center for Microelectromechanical Systems, Department of Mechanical Engineering, University of Minho, Guimarães, Portugal
| | - João Manuel Mendez Caramês
- Bone Physiology Research Group, LIBPhys, Faculty of Dental Medicine, Universidade de Lisboa, Lisboa, Portugal
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Abar B, Alonso-Calleja A, Kelly A, Kelly C, Gall K, West JL. 3D printing of high-strength, porous, elastomeric structures to promote tissue integration of implants. J Biomed Mater Res A 2020; 109:54-63. [PMID: 32418348 DOI: 10.1002/jbm.a.37006] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 04/10/2020] [Accepted: 04/19/2020] [Indexed: 12/19/2022]
Abstract
Despite advances in biomaterials research, there is no ideal device for replacing weight-bearing soft tissues like menisci or intervertebral discs due to poor integration with tissues and mechanical property mismatch. Designing an implant with a soft and porous tissue-contacting structure using a material conducive to cell attachment and growth could potentially address these limitations. Polycarbonate urethane (PCU) is a soft and tough biocompatible material that can be 3D printed into porous structures with controlled pore sizes. Porous biomaterials of appropriate chemistries can support cell proliferation and tissue ingrowth, but their optimal design parameters remain unclear. To investigate this, porous PCU structures were 3D-printed in a crosshatch pattern with a range of in-plane pore sizes (0 to 800 μm) forming fully interconnected porous networks. Printed porous structures had ultimate tensile strengths ranging from 1.9 to 11.6 MPa, strains to failure ranging from 300 to 486%, Young's moduli ranging from 0.85 to 12.42 MPa, and porosity ranging from 13 to 71%. These porous networks can be loaded with hydrogels, such as collagen gels, to provide additional biological support for cells. Bare PCU structures and collagen-hydrogel-filled porous PCU support robust NIH/3T3 fibroblast cell line proliferation over 14 days for all pore sizes. Results highlight PCU's potential in the development of tissue-integrating medical implants.
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Affiliation(s)
- Bijan Abar
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | | | - Alexander Kelly
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Cambre Kelly
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Ken Gall
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Jennifer L West
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
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Conrad TL, Roeder RK. Effects of porogen morphology on the architecture, permeability, and mechanical properties of hydroxyapatite whisker reinforced polyetheretherketone scaffolds. J Mech Behav Biomed Mater 2020; 106:103730. [DOI: 10.1016/j.jmbbm.2020.103730] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/08/2020] [Accepted: 03/13/2020] [Indexed: 11/16/2022]
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Basgul C, MacDonald DW, Siskey R, Kurtz SM. Thermal Localization Improves the Interlayer Adhesion and Structural Integrity of 3D printed PEEK Lumbar Spinal Cages. MATERIALIA 2020; 10:100650. [PMID: 32318685 PMCID: PMC7172383 DOI: 10.1016/j.mtla.2020.100650] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Additive manufacturing (AM) is a potential application for polyetheretherketone (PEEK) spinal interbody fusion cages, which were introduced as an alternative to titanium cages because of their biocompatibility, radiolucency and strength. However, AM of PEEK is challenging due to high melting temperature and thermal gradient. Although fused filament fabrication (FFF) techniques have been shown to 3D print PEEK, layer delamination was identified in PEEK cages printed with a first generation FFF PEEK printer [1]. A standard cage design [2] was 3D printed with a second generation FFF PEEK printer. The effect of changing layer cooling time on FFF cages' mechanical strength was investigated by varying nozzle sizes (0.2 mm and 0.4 mm), print speeds (1500 and 2500 mm/min), and the number of cages printed in a single build (1, 4 and 8). To calculate the porosity percentage, FFF cages were micro-CT scanned prior to destructive testing. Mechanical tests were then conducted on FFF cages according to ASTM F2077 [2]. Although altering the cooling time of a layer was not able to change the failure mechanism of FFF cages, it was able to improve cages' mechanical strength. Printing a single cage per build caused a higher ultimate load than printing multiple cages per build. Regardless of the cage number printed per build, cages printed with bigger nozzle diameter achieved higher ultimate load compared to cages printed with smaller nozzle diameter. Printing with a bigger nozzle diameter resulted in less porosity, which might have an additional affect on the interlayer delamination failure mechanism.
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Affiliation(s)
- Cemile Basgul
- Implant Research Center, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA
| | - Daniel W. MacDonald
- Implant Research Center, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA
| | - Ryan Siskey
- Implant Research Center, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA
- Exponent, Inc., Philadelphia, PA
| | - Steven M. Kurtz
- Implant Research Center, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA
- Exponent, Inc., Philadelphia, PA
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58
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Effects of Surface Topography and Chemistry on Polyether-Ether-Ketone (PEEK) and Titanium Osseointegration. Spine (Phila Pa 1976) 2020; 45:E417-E424. [PMID: 31703050 DOI: 10.1097/brs.0000000000003303] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An in vivo study examining the functional osseointegration of smooth, rough, and porous surface topographies presenting polyether-ether-ketone (PEEK) or titanium surface chemistry. OBJECTIVE To investigate the effects of surface topography and surface chemistry on implant osseointegration. SUMMARY OF BACKGROUND DATA Interbody fusion devices have been used for decades to facilitate fusion across the disc space, yet debate continues over their optimal surface topography and chemistry. Though both factors influence osseointegration, the relative effects of each are not fully understood. METHODS Smooth, rough, and porous implants presenting either a PEEK or titanium surface chemistry were implanted into the proximal tibial metaphyses of 36 skeletally mature male Sprague Dawley rats. At 8 weeks, animals were euthanized and bone-implant interfaces were subjected to micro-computed tomography analysis (n = 12), histology (n = 4), and biomechanical pullout testing (n = 8) to assess functional osseointegration and implant fixation. RESULTS Micro-computed tomography analysis demonstrated that bone ingrowth was 38.9 ± 2.8% for porous PEEK and 30.7 ± 3.3% for porous titanium (P = 0.07). No differences in fixation strength were detected between porous PEEK and porous titanium despite titanium surfaces exhibiting an overall increase in bone-implant contact compared with PEEK (P < 0.01). Porous surfaces exhibited increased fixation strength compared with smooth and rough surfaces regardless of surface chemistry (P < 0.05). Across all groups both surface topography and chemistry had a significant overall effect on fixation strength (P < 0.05), but topography accounted for 65.3% of the total variance (ω = 0.65), whereas surface chemistry accounted for 5.9% (ω = 0.06). CONCLUSIONS The effect of surface topography (specifically porosity) dominated the effect of surface chemistry in this study and could lead to further improvements in orthopedic device design. The poor osseointegration of existing smooth PEEK implants may be linked more to their smooth surface topography rather than their material composition. LEVEL OF EVIDENCE N/A.
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59
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Pereira HF, Cengiz IF, Silva FS, Reis RL, Oliveira JM. Scaffolds and coatings for bone regeneration. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2020; 31:27. [PMID: 32124052 DOI: 10.1007/s10856-020-06364-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/13/2020] [Indexed: 05/28/2023]
Abstract
Bone tissue has an astonishing self-healing capacity yet only for non-critical size defects (<6 mm) and clinical intervention is needed for critical-size defects and beyond that along with non-union bone fractures and bone defects larger than critical size represent a major healthcare problem. Autografts are, still, being used as preferred to treat large bone defects. Mostly, due to the presence of living differentiated and progenitor cells, its osteogenic, osteoinductive and osteoconductive properties that allow osteogenesis, vascularization, and provide structural support. Bone tissue engineering strategies have been proposed to overcome the limited supply of grafts. Complete and successful bone regeneration can be influenced by several factors namely: the age of the patient, health, gender and is expected that the ideal scaffold for bone regeneration combines factors such as bioactivity and osteoinductivity. The commercially available products have as their main function the replacement of bone. Moreover, scaffolds still present limitations including poor osteointegration and limited vascularization. The introduction of pores in scaffolds are being used to promote the osteointegration as it allows cell and vessel infiltration. Moreover, combinations with growth factors or coatings have been explored as they can improve the osteoconductive and osteoinductive properties of the scaffold. This review focuses on the bone defects treatments and on the research of scaffolds for bone regeneration. Moreover, it summarizes the latest progress in the development of coatings used in bone tissue engineering. Despite the interesting advances which include the development of hybrid scaffolds, there are still important challenges that need to be addressed in order to fasten translation of scaffolds into the clinical scenario. Finally, we must reflect on the main challenges for bone tissue regeneration. There is a need to achieve a proper mechanical properties to bear the load of movements; have a scaffolds with a structure that fit the bone anatomy.
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Affiliation(s)
- Helena Filipa Pereira
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, University of Minho, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, Barco, 4805-017, Guimarães, Portugal.
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
- Center for Micro-Electro Mechanical Systems, University of Minho, Azurém Campus, 4800-058, Guimarães, Portugal.
| | - Ibrahim Fatih Cengiz
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, University of Minho, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, Barco, 4805-017, Guimarães, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
- The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, AvePark, Barco, 4805-017, Guimarães, Portugal
| | - Filipe Samuel Silva
- Center for Micro-Electro Mechanical Systems, University of Minho, Azurém Campus, 4800-058, Guimarães, Portugal
| | - Rui Luís Reis
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, University of Minho, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, Barco, 4805-017, Guimarães, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
- The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, AvePark, Barco, 4805-017, Guimarães, Portugal
| | - Joaquim Miguel Oliveira
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, University of Minho, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, Barco, 4805-017, Guimarães, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
- The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, AvePark, Barco, 4805-017, Guimarães, Portugal
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Pastukhov LV, Kanters MJW, Engels TAP, Govaert LE. Physical background of the endurance limit in poly(ether ether ketone). JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1002/pol.20190091] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Leonid V. Pastukhov
- Polymer TechnologyEindhoven University of Technology Eindhoven The Netherlands
- Dutch Polymer Institute (DPI) Eindhoven The Netherlands
| | - Marc J. W. Kanters
- Polymer TechnologyEindhoven University of Technology Eindhoven The Netherlands
| | - Tom A. P. Engels
- Polymer TechnologyEindhoven University of Technology Eindhoven The Netherlands
| | - Leon E. Govaert
- Polymer TechnologyEindhoven University of Technology Eindhoven The Netherlands
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Does annealing improve the interlayer adhesion and structural integrity of FFF 3D printed PEEK lumbar spinal cages? J Mech Behav Biomed Mater 2020; 102:103455. [DOI: 10.1016/j.jmbbm.2019.103455] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 11/19/2022]
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Kumar S, Nehra M, Kedia D, Dilbaghi N, Tankeshwar K, Kim KH. Nanotechnology-based biomaterials for orthopaedic applications: Recent advances and future prospects. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 106:110154. [DOI: 10.1016/j.msec.2019.110154] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/04/2019] [Accepted: 08/31/2019] [Indexed: 12/13/2022]
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Mixed Modification of the Surface Microstructure and Chemical State of Polyetheretherketone to Improve Its Antimicrobial Activity, Hydrophilicity, Cell Adhesion, and Bone Integration. ACS Biomater Sci Eng 2019; 6:842-851. [DOI: 10.1021/acsbiomaterials.9b01148] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Li Y, Wang J, He D, Wu G, Chen L. Surface sulfonation and nitrification enhance the biological activity and osteogenesis of polyetheretherketone by forming an irregular nano-porous monolayer. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2019; 31:11. [PMID: 31875263 DOI: 10.1007/s10856-019-6349-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
Polyether-ether-ketone (PEEK) is becoming a popular component of clinical spinal and orthopedic applications, but its practical use suffers from several limitations. In this study, irregular nano-porous monolayer with differently functional groups was formed on the surface of PEEK through sulfonation and nitrification. The surface characteristics were detected by field-emission scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectrometry, water contact angle measurements and Fourier transform infrared spectroscopy. In vitro cellular behaviors were evaluated by cell adhesion, morphological changes, proliferation, alkalinity, phosphatase activity, real-time RT-PCR and western blot analyses. In vivo osseointegration was examined through micro-CT and histological assessments. Our results reveal that the irregular nano-porous of PEEK affect the biological properties. High-temperature hydrothermal NP treatment induced early osteogenic differentiation and early osteogenesis. Modification by sulfonation and nitrification can broaden the use of PEEK in orthopedic and dental applications. This study provides a theoretical basis for the wider clinical application of PEEK. a To obtain a uniform porous structure, PEEK samples were treated by concentrated sulfuric acid and fuming nitric acid (82-80%) with magnetic stirring sequentially. b Effects of nanopores on biological behavior of bMSCS.
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Affiliation(s)
- Yanhua Li
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Wenhua Xi Road No. 44-1, Jinan, 250012, Shandong, PR China
- Department of Orthodontics, School of Stomatology, Shandong University, Jinan, Shandong, PR China
| | - Jing Wang
- Department of Stomatology, PLA 960th hospital, Jinan, 250031, Shandong, PR China
| | - Dong He
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Wenhua Xi Road No. 44-1, Jinan, 250012, Shandong, PR China
- Department of Orthodontics, School of Stomatology, Shandong University, Jinan, Shandong, PR China
| | - Gaoyi Wu
- Department of Stomatology, PLA 960th hospital, Jinan, 250031, Shandong, PR China
| | - Lei Chen
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Wenhua Xi Road No. 44-1, Jinan, 250012, Shandong, PR China.
- Department of Orthodontics, School of Stomatology, Shandong University, Jinan, Shandong, PR China.
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Knaus J, Schaffarczyk D, Cölfen H. On the Future Design of Bio-Inspired Polyetheretherketone Dental Implants. Macromol Biosci 2019; 20:e1900239. [PMID: 31802617 DOI: 10.1002/mabi.201900239] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 10/10/2019] [Indexed: 11/09/2022]
Abstract
Polyetheretherketone (PEEK) is a promising implant material because of its excellent mechanical characteristics. Although this polymer is a standard material in spinal applications, PEEK is not in use in the manufacturing of dental implants, where titanium is still the most-used material. This may be caused by its relative bio-inertness. By the use of various surface modification techniques, efforts have been made to enhance its osseointegrative characteristics to enable the polymer to be used in dentistry. In this feature paper, the state-of-the-art for dental implants is given and different surface modification techniques of PEEK are discussed. The focus will lie on a covalently attached surface layer mimicking natural bone. The usage of such covalently anchored biomimetic composite materials combines many advantageous properties: A biocompatible organic matrix and a mineral component provide the cells with a surrounding close to natural bone. Bone-related cells may not recognize the implant as a foreign body and therefore, may heal and integrate faster and more firmly. Because neither metal-based nor ceramics are ideal material candidates for a dental implant, the combination of PEEK and a covalently anchored mineralized biopolymer layer may be the start of the desired evolution in dental surgery.
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Affiliation(s)
- Jennifer Knaus
- Department of Chemistry, Physical Chemistry, University of Konstanz, Universitätsstraße 10, 78457, Konstanz, Germany.,stimOS GmbH, Byk-Gulden-Straße 2, 78467, Konstanz, Germany
| | | | - Helmut Cölfen
- Department of Chemistry, Physical Chemistry, University of Konstanz, Universitätsstraße 10, 78457, Konstanz, Germany
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Buck E, Li H, Cerruti M. Surface Modification Strategies to Improve the Osseointegration of Poly(etheretherketone) and Its Composites. Macromol Biosci 2019; 20:e1900271. [DOI: 10.1002/mabi.201900271] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 10/18/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Emily Buck
- Department of Mining and Materials EngineeringMcGill University 3610 University Street Montreal QC H3A 0C5 Canada
| | - Hao Li
- Department of Mining and Materials EngineeringMcGill University 3610 University Street Montreal QC H3A 0C5 Canada
| | - Marta Cerruti
- Department of Mining and Materials EngineeringMcGill University 3610 University Street Montreal QC H3A 0C5 Canada
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67
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Zhong G, Vaezi M, Mei X, Liu P, Yang S. Strategy for Controlling the Properties of Bioactive Poly-Ether-Ether-Ketone/Hydroxyapatite Composites for Bone Tissue Engineering Scaffolds. ACS OMEGA 2019; 4:19238-19245. [PMID: 31763547 PMCID: PMC6868901 DOI: 10.1021/acsomega.9b02572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
A strategy for the preparation of bioactive poly-ether-ether-ketone/hydroxyapatite (PEEK/HA) composites was proposed in this study with the aim of controlling the biological and mechanical properties of different parts of the composites. The strategy integrated solvent-based extrusion freeforming 3D printing technology in order to print high-resolution HA scaffolds and compression molding processes for the production of bioactive PEEK/HA composites. To this end, an optimized model, established using response surface methodology, was employed to optimize the extrusion process parameters on the basis of accurate characterization of the extrusion pressure, and the effects of the filament/pore sizes on the PEEK infiltration depth into the HA scaffold were investigated. The results of scanning electron microscopy and computed tomography analyses revealed that the PEEK/HA composites exhibited a uniform microstructure and a good interface between the HA filaments and the PEEK matrix following the optimization of the process parameters. The HA scaffolds were fully infiltrated by PEEK in both vertical and lateral directions with an infiltration depth of 3 mm while maintaining the HA network structure and uniformity. The biological and mechanical performance test results validated that the PEEK/HA composites possessed excellent biocompatibility as well as yields and compressive strengths within the range of human cortical bone suitable for load-bearing applications.
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Affiliation(s)
- Gaoyan Zhong
- College
of Engineering, Nanjing Agricultural University, Nanjing 210031, Jiangsu, China
- Faculty
of Engineering and the Environment, University
of Southampton, Southampton SO17 1BJ, Hampshire, U.K.
- State
Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
| | - Mohammad Vaezi
- Faculty
of Engineering and the Environment, University
of Southampton, Southampton SO17 1BJ, Hampshire, U.K.
- Department
of Mechanical Engineering and Marine Technology, University of Rostock, Rostock 18059, Germany
- Department
of Mechanical Engineering, Babol Noshirvani
University of Technology, Babol 4714871167, Mazandaran, Iran
| | - Xinliang Mei
- College
of Engineering, Nanjing Agricultural University, Nanjing 210031, Jiangsu, China
| | - Ping Liu
- College
of Engineering, Nanjing Agricultural University, Nanjing 210031, Jiangsu, China
| | - Shoufeng Yang
- College
of Engineering, Nanjing Agricultural University, Nanjing 210031, Jiangsu, China
- Faculty
of Engineering and the Environment, University
of Southampton, Southampton SO17 1BJ, Hampshire, U.K.
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68
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Bi-directional regulatable mechanical properties of 3D braided polyetheretherketone (PEEK). MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 103:109811. [DOI: 10.1016/j.msec.2019.109811] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/08/2019] [Accepted: 05/27/2019] [Indexed: 02/05/2023]
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69
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Li Y, Wang D, Qin W, Jia H, Wu Y, Ma J, Tang B. Mechanical properties, hemocompatibility, cytotoxicity and systemic toxicity of carbon fibers/poly(ether-ether-ketone) composites with different fiber lengths as orthopedic implants. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2019; 30:1709-1724. [PMID: 31464157 DOI: 10.1080/09205063.2019.1659711] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Poly(ether-ether-ketone) (PEEK) has attracted more and more attention due to its chemical resistance, biocompatibility and other properties. Furthermore, carbon fibers-PEEK composite (CF-PEEK) has been considered as a novel implant because of its high mechanical strength and elastic modulus that matching with human bones. However, the length of CF has a great influence on mechanical strength and elastic modulus of the randomly distributed chopped CF-PEEK composites. In this work, CF-PEEK composites with more than 10 times length difference of fibers (length of short CF: 150-200 μm and length of long CF: 2-3 mm) were studied. As the results shown, the mechanical strength (including tensile strength, bending strength and compressive strength) of long CF-PEEK composites were more than two times of that of short CF-PEEK composites. Meanwhile, tensile modulus and bending modulus of the two kinds of composites matched well with the modulus of human cortical bone. In addition, according to the results of cytotoxicity test and hemocompatibility assessment, it indicated that the two kinds of CF-PEEK composites showed mild toxicity and no hemolytic reaction. And the histopathological section of systemic toxicity test showed that the CF-PEEK composites had no obvious acute toxicity to organisms.
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Affiliation(s)
- Ying Li
- Changhai Hospital, The Second Military Medical University , Yangpu Qu , China.,Dental Medicine MDT Center, The First Hospital of Shanxi Medical University , Taiyuan , China
| | - Dalin Wang
- Department of Stomatology, Changhai Hospital, The Second Military Medical University , Yangpu Qu , China
| | - Wen Qin
- Institute of New Carbon Materials, Taiyuan University of Technology , Taiyuan , China
| | - Hui Jia
- Department of Stomatology, Shanxi Medical University , Taiyuan , China
| | - Yang Wu
- Department of Stomatology, Shanxi Medical University , Taiyuan , China
| | - Jing Ma
- Institute of New Carbon Materials, Taiyuan University of Technology , Taiyuan , China
| | - Bin Tang
- Institute of New Carbon Materials, Taiyuan University of Technology , Taiyuan , China
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Gunzburg R, Colloca CJ, Jones CF, Hall DJ, McAviney J, Callary S, Hegazy MA, Szpalski M, Freeman BJC. Does nanoscale porous titanium coating increase lumbar spinal stiffness of an interbody fusion cage? An in vivo biomechanical analysis in an ovine model. Clin Biomech (Bristol, Avon) 2019; 67:187-196. [PMID: 31176064 DOI: 10.1016/j.clinbiomech.2019.04.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Quantitative objective measures to determine fusion achievement further enable the comparison of new technologies, such as interbody cage surface enhancement. Our aims were to compare in vivo biomechanical responses of ovine L4/5 lumbar motion segments with two cages: 1) Polyetheretherketone or 2) Polyetheretherketone with a nanosurfaced titanium porous scaffold from Nanovis, Inc. METHODS Fourteen Merino sheep randomly received either 1) standard Polyetheretherketone cage or 2) Nanocoated Polyetheretherketone cage at L4/L5 with autologous bone graft. At baseline and one-year follow-up, dynamic spinal stiffness was quantified in vivo using a validated mechanical assessment at 2 Hz, 6 Hz, and 12 Hz. The dorsoventral secant stiffness (ky = force/displacement, N/mm) and L4-L5 accelerations were determined at each frequency. A repeated measures analysis of variance with Bonferonni correction was used to evaluate within and between group differences among the biomechanical variables. FINDINGS Both implants increased spinal stiffness at 2 Hz (21 and 39%, respectively, p < .005), and at 6 Hz (12 and 27%, p < .0001). Significantly greater spinal stiffness was observed with Nanocoated Polyetheretherketone at one-year for both frequencies (p < .05). No significant differences were observed at 12 Hz within or between groups. L4-L5 dorsoventral accelerations were significantly decreased one year following cage placement only with Nanocoated Polyetheretherketone (p < .05) and greater reductions in acceleration were observed with Nanocoated Polyetheretherketone compared to standard Polyetheretherketone (p < .05). INTERPRETATION Both cages increased spinal stiffness, yet, nanosurfaced cages resulted in greater spinal stiffness changes and decreases in L4-L5 accelerations. These findings may assist in clinical decision making and post-operative recovery strategies.
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Affiliation(s)
- Robert Gunzburg
- Department of Orthopaedic Surgery, Edith Cavell Clinic, Brussels, Belgium.
| | | | - Claire F Jones
- Adelaide Centre for Spinal Research, SA Pathology, Adelaide, Australia; Centre for Orthopaedic and Trauma Research, University of Adelaide, Australia
| | - David J Hall
- Adelaide Centre for Spinal Research, SA Pathology, Adelaide, Australia; Department of Spinal Surgery, Royal Adelaide Hospital, Adelaide, Australia
| | | | - Stuart Callary
- School of Mechanical Engineering, University of Adelaide, Australia
| | - Mostafa A Hegazy
- Science Department, Southwest Minnesota State University, Marshall, MN, USA
| | - Marek Szpalski
- Department of Orthopedics, Hôpitaux Iris Sud/IRIS South Teaching Hospitals, Brussels, Belgium
| | - Brian J C Freeman
- Adelaide Centre for Spinal Research, SA Pathology, Adelaide, Australia; Centre for Orthopaedic and Trauma Research, University of Adelaide, Australia; Department of Spinal Surgery, Royal Adelaide Hospital, Adelaide, Australia
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71
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Polymers for additive manufacturing and 4D-printing: Materials, methodologies, and biomedical applications. Prog Polym Sci 2019. [DOI: 10.1016/j.progpolymsci.2019.03.001] [Citation(s) in RCA: 243] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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72
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Carpenter RD, Klosterhoff BS, Torstrick FB, Foley KT, Burkus JK, Lee CSD, Gall K, Guldberg RE, Safranski DL. Effect of porous orthopaedic implant material and structure on load sharing with simulated bone ingrowth: A finite element analysis comparing titanium and PEEK. J Mech Behav Biomed Mater 2019; 80:68-76. [PMID: 29414477 DOI: 10.1016/j.jmbbm.2018.01.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 12/29/2022]
Abstract
Osseointegration of load-bearing orthopaedic implants, including interbody fusion devices, is critical to long-term biomechanical functionality. Mechanical loads are a key regulator of bone tissue remodeling and maintenance, and stress-shielding due to metal orthopaedic implants being much stiffer than bone has been implicated in clinical observations of long-term bone loss in tissue adjacent to implants. Porous features that accommodate bone ingrowth have improved implant fixation in the short term, but long-term retrieval studies have sometimes demonstrated limited, superficial ingrowth into the pore layer of metal implants and aseptic loosening remains a problem for a subset of patients. Polyether-ether-ketone (PEEK) is a widely used orthopaedic material with an elastic modulus more similar to bone than metals, and a manufacturing process to form porous PEEK was recently developed to allow bone ingrowth while preserving strength for load-bearing applications. To investigate the biomechanical implications of porous PEEK compared to porous metals, we analyzed finite element (FE) models of the pore structure-bone interface using two clinically available implants with high (> 60%) porosity, one being constructed from PEEK and the other from electron beam 3D-printed titanium (Ti). The objective of this study was to investigate how porous PEEK and porous Ti mechanical properties affect load sharing with bone within the porous architectures over time. Porous PEEK substantially increased the load share transferred to ingrown bone compared to porous Ti under compression (i.e. at 4 weeks: PEEK = 66%; Ti = 13%), tension (PEEK = 71%; Ti = 12%), and shear (PEEK = 68%; Ti = 9%) at all time points of simulated bone ingrowth. Applying PEEK mechanical properties to the Ti implant geometry and vice versa demonstrated that the observed increases in load sharing with PEEK were primarily due to differences in intrinsic elastic modulus and not pore architecture (i.e. 4 weeks, compression: PEEK material/Ti geometry = 53%; Ti material/PEEK geometry = 12%). Additionally, local tissue energy effective strains on bone tissue adjacent to the implant under spinal load magnitudes were over two-fold higher with porous PEEK than porous Ti (i.e. 4 weeks, compression: PEEK = 784 ± 351 microstrain; Ti = 180 ± 300 microstrain; and 12 weeks, compression: PEEK = 298 ± 88 microstrain; Ti = 121 ± 49 microstrain). The higher local strains on bone tissue in the PEEK pore structure were below previously established thresholds for bone damage but in the range necessary for physiological bone maintenance and adaptation. Placing these strain magnitudes in the context of literature on bone adaptation to mechanical loads, this study suggests that porous PEEK structures may provide a more favorable mechanical environment for bone formation and maintenance under spinal load magnitudes than currently available porous 3D-printed Ti, regardless of the level of bone ingrowth.
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Affiliation(s)
- R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, USA.
| | - Brett S Klosterhoff
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - F Brennan Torstrick
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kevin T Foley
- Departments of Neurosurgery, Orthopaedic Surgery, and Biomedical Engineering, University of Tennessee Health Sciences Center, Memphis, TN, USA; Semmes-Murphey Neurologic & Spine Institute, Memphis, TN, USA
| | | | | | - Ken Gall
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA; Vertera Inc., Atlanta, GA, USA; MedShape Inc., Atlanta, GA, USA
| | - Robert E Guldberg
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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74
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Feng P, He J, Peng S, Gao C, Zhao Z, Xiong S, Shuai C. Characterizations and interfacial reinforcement mechanisms of multicomponent biopolymer based scaffold. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 100:809-825. [PMID: 30948118 DOI: 10.1016/j.msec.2019.03.030] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 03/02/2019] [Accepted: 03/09/2019] [Indexed: 12/20/2022]
Abstract
It is difficult for a single component biopolymer to meet the requirements of scaffold at present. The development of multicomponent biopolymer based scaffold provides an effective method to solve the issue based on the advantages of each kind of the biomaterials. However, the compatibility between different components might be very poor due to the difficulties in forming strong interfacial bonding, and thereby significantly degrading the integrated mechanical properties of the scaffold. In recent years, interface phase introduction, surface modification and in situ growth have been the major strategies for enhancing interfacial bonding. This article presents a comprehensive overview on the research in the area of constructing multicomponent biopolymer based scaffold and reinforcing their interfacial properties, and more importantly, the interfacial bonding mechanisms are systematically summarized. Detailly, interface phase introduction can build a bridge between biopolymer and other components to form strong interface bonding with the two phases under the action of interface phase. Surface modification can graft organic molecules or polymers containing functional groups onto other components to crosslink with biopolymer. In situ growth can directly in situ synthesize other components with the action of nucleating agent serving as an adherent platform for the nucleation and growth of other components to biopolymer surface by chemical bonding. In addition, the mechanical properties (including strength and modulus) and biological properties (including bioactivity, cytocompatibility and biosensing in vitro, and tissue compatibility, bone regeneration capacity in vivo) of multicomponent biopolymer based scaffold after interfacial reinforcing are also reviewed and discussed. Finally, suggestions for further research are given with highlighting the need for specific investigations to assess the interface formation, structure, properties, and more in vivo studies of scaffold before applications.
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Affiliation(s)
- Pei Feng
- State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
| | - Jiyao He
- State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
| | - Shuping Peng
- Hunan Provincial Tumor Hospital and the Affiliated Tumor Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, China
| | - Chengde Gao
- State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
| | - Zhenyu Zhao
- Shenzhen Institute of Information Technology, Shenzhen 518172, China
| | - Shixian Xiong
- Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Cijun Shuai
- State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China; Jiangxi University of Science and Technology, Ganzhou 341000, China; Shenzhen Institute of Information Technology, Shenzhen 518172, China.
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75
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Wetting Properties of Polyetheretherketone Plasma Activated and Biocoated Surfaces. COLLOIDS AND INTERFACES 2019. [DOI: 10.3390/colloids3010040] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Polyetheretherketone (PEEK) biomaterial is a polymer which has been widely used since the early 90s as a material for human bone implant preparations. Nowadays it is increasingly used due to its high biocompatibility and easily modeling, as well as better mechanical properties and price compared to counterparts made of titanium or platinum alloys. In this paper, air low-temperature and pressure plasma was used to enhance PEEK adhesive properties as well as surface sterilization. On the activated polymeric carrier, biologically-active substances have been deposited with the Langmuir-Blodgett technique. Thereafter, the surface was characterized using optical profilometry, and wettability was examined by contact angle measuring. Next, the contact angle hysteresis (CAH) model was used to calculate the surface free energy of the modified surface of PEEK. The variations of wettability and surface free energy were observed depending on the deposited monolayer type and its components.
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76
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Multifunctional sulfonated polyetheretherketone coating with beta-defensin-14 for yielding durable and broad-spectrum antibacterial activity and osseointegration. Acta Biomater 2019; 86:323-337. [PMID: 30641289 DOI: 10.1016/j.actbio.2019.01.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 12/14/2022]
Abstract
To address periprosthetic joint infection (PJI), a formidable complication after joint arthroplasty, an implant with excellent osseointegration and effective antibacterial activity has being extensively pursued and developed. In this work, the mouse beta-defensin-14 (MBD-14) was immobilized on the polyetheretherketone (PEEK) surface with three-dimensional (3D) porous structure to improve its antibacterial activity and osseointegration. An in vitro antibacterial evaluation showed that the porous PEEK loaded with MBD-14 wages a durable and effective fight against both Staphylococcus aureus (gram-positive) and Pseudomonas aeruginosa (gram-negative). In addition to the superior antibacterial activity, we found that the enhanced proliferation and osteogenic differentiation of bone mesenchymal stem cells were verified through various in vitro analyses. To evaluate the in vivo bactericidal effect and osseointegration of the samples, the rat femoral models with infection and non-infection were established. The enhanced osseointegration of the MBD-14-loaded samples was found in both two in vivo models. And no bacteria survived on the surfaces of samples with a relatively high MBD-14 concentration. Above results indicate that the 3D porous PEEK coating loaded with MBD-14 simultaneously yields excellent osseointegration while exerting durable and broad-spectrum antibacterial activity. And it paves the way for PEEK to be applied clinically to address PJI. STATEMENT OF SIGNIFICANCE: (1). By using the physio-chemical technique including sulfonation and lyophilization etc., a three-dimensional porous network is developed on polyetheretherketone (PEEK) surface, in which mouse beta-defensin-14 (MBD-14, a broad-spectrum antimicrobial peptide) is then loaded. It endows PEEK with antibacterial activity and osseointegration. (2). Two in vivo animal models with infection and non-infection are used to prove the new bone formation around the samples. (3). Supplementary material also proves that MBD-14 promotes the osteogenic differentiation of BMSCs. However, its potential mechanism needs to be further studied in future. (4). The modified PEEK, including excellent osseointegration and a durable and broad-spectrum antibacterial activity, could be applied clinically to address PJI which is a hot potato for surgeons and patients undergoing total joint arthroplasty.
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77
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Fukuda N, Tsuchiya A, Sunarso, Toita R, Tsuru K, Mori Y, Ishikawa K. Surface plasma treatment and phosphorylation enhance the biological performance of poly(ether ether ketone). Colloids Surf B Biointerfaces 2019; 173:36-42. [DOI: 10.1016/j.colsurfb.2018.09.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 08/05/2018] [Accepted: 09/13/2018] [Indexed: 01/29/2023]
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Tomoglu S, Caner G, Arabaci A, Mutlu I. Production and sulfonation of bioactive polyetheretherketone foam for bone substitute applications. INT J POLYM MATER PO 2018. [DOI: 10.1080/00914037.2018.1539985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Saitali Tomoglu
- Metallurgical and Materials Engineering Department, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Gulnihal Caner
- Metallurgical and Materials Engineering Department, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Aliye Arabaci
- Metallurgical and Materials Engineering Department, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Ilven Mutlu
- Metallurgical and Materials Engineering Department, Istanbul University-Cerrahpasa, Istanbul, Turkey
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79
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Torstrick FB, Lin AS, Potter D, Safranski DL, Sulchek TA, Gall K, Guldberg RE. Porous PEEK improves the bone-implant interface compared to plasma-sprayed titanium coating on PEEK. Biomaterials 2018; 185:106-116. [DOI: 10.1016/j.biomaterials.2018.09.009] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 08/31/2018] [Accepted: 09/07/2018] [Indexed: 12/14/2022]
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80
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Qin W, Li Y, Ma J, Liang Q, Tang B. Mechanical properties and cytotoxicity of hierarchical carbon fiber-reinforced poly (ether-ether-ketone) composites used as implant materials. J Mech Behav Biomed Mater 2018; 89:227-233. [PMID: 30296704 DOI: 10.1016/j.jmbbm.2018.09.040] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/19/2018] [Accepted: 09/25/2018] [Indexed: 11/27/2022]
Abstract
Weak mechanical properties affect the application of PEEK as an implant. Carbon fiber (CFR) reinforcement provides an excellent solution to improve the mechanical strength of PEEK and to provide perfect matching of elastic modulus between CFR-PEEK composites and human bone. To investigate the effect of carbon fiber content on the mechanical, thermal properties and cytotoxicity of CFR reinforced PEEK composites, a series of CFR-PEEK composites with different carbon fiber content (25 wt%, 30 wt%, 35 wt%, 40 wt%) was prepared in this work. Thermal decomposition behavior and melting temperature were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. Subsequently, mechanical properties including bending strength, compressive strength, impact strength and hardness were tested respectively. Afterwards, the fracture morphology of the bending test samples was observed by scanning electron microscopy (SEM). In addition, murine fibroblast L929 cells were adopted for cytotoxicity test by CCK-8 assay in vitro, and the morphology of cells was observed by inverted fluorescence microscope simultaneously, cell compatibility of CFR-PEEK composites was tested.
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Affiliation(s)
- Wen Qin
- School of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Ying Li
- Department of Prosthodontics, The First Hospital of Shanxi Medical University, Taiyuan 030001, China
| | - Jing Ma
- School of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Qian Liang
- School of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Bin Tang
- School of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
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Kassick AJ, Yerneni SS, Gottlieb E, Cartieri F, Peng Y, Mao G, Kharlamov A, Miller MC, Xu C, Oh M, Kowalewski T, Cheng B, Campbell PG, Averick S. Osteoconductive Enhancement of Polyether Ether Ketone: A Mild Covalent Surface Modification Approach. ACS APPLIED BIO MATERIALS 2018; 1:1047-1055. [DOI: 10.1021/acsabm.8b00274] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew J. Kassick
- Neuroscience Disruptive Research Lab, Allegheny Health Network Research Institute, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
- Neuroscience Institute, Allegheny Health Network, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
| | - Saigopalakrishna S. Yerneni
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15217, United States
| | - Eric Gottlieb
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15217, United States
| | - Francis Cartieri
- Department of Surgery Allegheny Health Network, West Penn Hospital, Pittsburgh, Pennsylvania 15212, United States
| | - Yushuan Peng
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15217, United States
| | - Gordon Mao
- Neuroscience Institute, Allegheny Health Network, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
| | - Alexander Kharlamov
- Department of Orthopedic Surgery, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
| | - Mark C. Miller
- Department of Orthopedic Surgery, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
- Departments of Mechanical Engineering and Materials Science & Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Chen Xu
- Neuroscience Institute, Allegheny Health Network, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
| | - Michael Oh
- Neuroscience Institute, Allegheny Health Network, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
| | - Tomasz Kowalewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15217, United States
| | - Boyle Cheng
- Neuroscience Institute, Allegheny Health Network, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
| | - Phil G. Campbell
- Department of Biomedical Engineering and Engineering Research Accelerator, Carnegie Mellon University, Pittsburgh, Pennsylvania 15217, United States
| | - Saadyah Averick
- Neuroscience Disruptive Research Lab, Allegheny Health Network Research Institute, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
- Neuroscience Institute, Allegheny Health Network, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, United States
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82
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Yuan B, Cheng Q, Zhao R, Zhu X, Yang X, Yang X, Zhang K, Song Y, Zhang X. Comparison of osteointegration property between PEKK and PEEK: Effects of surface structure and chemistry. Biomaterials 2018; 170:116-126. [DOI: 10.1016/j.biomaterials.2018.04.014] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/05/2018] [Accepted: 04/07/2018] [Indexed: 10/17/2022]
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83
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Torstrick FB, Klosterhoff BS, Westerlund LE, Foley KT, Gochuico J, Lee CSD, Gall K, Safranski DL. Impaction durability of porous polyether-ether-ketone (PEEK) and titanium-coated PEEK interbody fusion devices. Spine J 2018; 18:857-865. [PMID: 29366985 DOI: 10.1016/j.spinee.2018.01.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/01/2017] [Accepted: 01/10/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Various surface modifications, often incorporating roughened or porous surfaces, have recently been introduced to enhance osseointegration of interbody fusion devices. However, these topographical features can be vulnerable to damage during clinical impaction. Despite the potential negative impact of surface damage on clinical outcomes, current testing standards do not replicate clinically relevant impaction loading conditions. PURPOSE The purpose of this study was to compare the impaction durability of conventional smooth polyether-ether-ketone (PEEK) cervical interbody fusion devices with two surface-modified PEEK devices that feature either a porous structure or plasma-sprayed titanium coating. STUDY DESIGN/SETTING A recently developed biomechanical test method was adapted to simulate clinically relevant impaction loading conditions during cervical interbody fusion procedures. METHODS Three cervical interbody fusion devices were used in this study: smooth PEEK, plasma-sprayed titanium-coated PEEK, and porous PEEK (n=6). Following Kienle et al., devices were impacted between two polyurethane blocks mimicking vertebral bodies under a constant 200 N preload. The posterior tip of the device was placed at the entrance between the polyurethane blocks, and a guided 1-lb weight was impacted upon the anterior face with a maximum speed of 2.6 m/s to represent the strike force of a surgical mallet. Impacts were repeated until the device was fully impacted. Porous PEEK durability was assessed using micro-computed tomography (µCT) pre- and postimpaction. Titanium-coating coverage pre- and postimpaction was assessed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. Changes to the surface roughness of smooth and titanium-coated devices were also evaluated. RESULTS Porous PEEK and smooth PEEK devices showed minimal macroscopic signs of surface damage, whereas the titanium-coated devices exhibited substantial visible coating loss. Quantification of the porous PEEK deformation demonstrated that the porous structure maintained a high porosity (>65%) following impaction that would be available for bone ingrowth, and exhibited minimal changes to pore size and depth. SEM and energy dispersive X-ray spectroscopy analysis of titanium-coated devices demonstrated substantial titanium coating loss after impaction that was corroborated with a decrease in surface roughness. Smooth PEEK showed minimal signs of damage using SEM, but demonstrated a decrease in surface roughness. CONCLUSION Although recent surface modifications to interbody fusion devices are beneficial for osseointegration, they may be susceptible to damage and wear during impaction. The current study found porous PEEK devices to show minimal damage during simulated cervical impaction, whereas titanium-coated PEEK devices lost substantial titanium coverage.
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Affiliation(s)
- F Brennan Torstrick
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332
| | - Brett S Klosterhoff
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332
| | - L Erik Westerlund
- St. Francis Spine Center, St. Francis Hospital, 2300 Manchester Expressway, Columbus, GA 31904
| | - Kevin T Foley
- Neurologic & Spine Institute, Semmes-Murphey Clinic, 6325 Humphreys Blvd, Memphis, TN 38120; Department of Neurosurgery, University of Tennessee Health Science Center, 847 Monroe Ave Suite 427, Memphis, TN 38163
| | - Joanna Gochuico
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332; Vertera, Inc, 739 Trabert Ave NW Suite B, Atlanta, GA 30318
| | | | - Ken Gall
- Vertera, Inc, 739 Trabert Ave NW Suite B, Atlanta, GA 30318; Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, NC 27708; MedShape, Inc., 1575 Northside Dr NW Suite 440, Atlanta, GA 30318
| | - David L Safranski
- Vertera, Inc, 739 Trabert Ave NW Suite B, Atlanta, GA 30318; MedShape, Inc., 1575 Northside Dr NW Suite 440, Atlanta, GA 30318.
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84
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Ahn H, Patel RR, Hoyt AJ, Lin ASP, Torstrick FB, Guldberg RE, Frick CP, Carpenter RD, Yakacki CM, Willett NJ. Biological evaluation and finite-element modeling of porous poly(para-phenylene) for orthopaedic implants. Acta Biomater 2018; 72:352-361. [PMID: 29563069 DOI: 10.1016/j.actbio.2018.03.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 12/22/2022]
Abstract
Poly(para-phenylene) (PPP) is a novel aromatic polymer with higher strength and stiffness than polyetheretherketone (PEEK), the gold standard material for polymeric load-bearing orthopaedic implants. The amorphous structure of PPP makes it relatively straightforward to manufacture different architectures, while maintaining mechanical properties. PPP is promising as a potential orthopaedic material; however, the biocompatibility and osseointegration have not been well investigated. The objective of this study was to evaluate biological and mechanical behavior of PPP, with or without porosity, in comparison to PEEK. We examined four specific constructs: 1) solid PPP, 2) solid PEEK, 3) porous PPP and 4) porous PEEK. Pre-osteoblasts (MC3T3) exhibited similar cell proliferation among the materials. Osteogenic potential was significantly increased in the porous PPP scaffold as assessed by ALP activity and calcium mineralization. In vivo osseointegration was assessed by implanting the cylindrical materials into a defect in the metaphysis region of rat tibiae. Significantly more mineral ingrowth was observed in both porous scaffolds compared to the solid scaffolds, and porous PPP had a further increase compared to porous PEEK. Additionally, porous PPP implants showed bone formation throughout the porous structure when observed via histology. A computational simulation of mechanical push-out strength showed approximately 50% higher interfacial strength in the porous PPP implants compared to the porous PEEK implants and similar stress dissipation. These data demonstrate the potential utility of PPP for orthopaedic applications and show improved osseointegration when compared to the currently available polymeric material. STATEMENT OF SIGNIFICANCE PEEK has been widely used in orthopaedic surgery; however, the ability to utilize PEEK for advanced fabrication methods, such as 3D printing and tailored porosity, remain challenging. We present a promising new orthopaedic biomaterial, Poly(para-phenylene) (PPP), which is a novel class of aromatic polymers with higher strength and stiffness than polyetheretherketone (PEEK). PPP has exceptional mechanical strength and stiffness due to its repeating aromatic rings that provide strong anti-rotational biaryl bonds. Furthermore, PPP has an amorphous structure making it relatively easier to manufacture (via molding or solvent-casting techniques) into different geometries with and without porosity. This ability to manufacture different architectures and use different processes while maintaining mechanical properties makes PPP a very promising potential orthopaedic biomaterial which may allow for closer matching of mechanical properties between the host bone tissue while also allowing for enhanced osseointegration. In this manuscript, we look at the potential of porous and solid PPP in comparison to PEEK. We measured the mechanical properties of PPP and PEEK scaffolds, tested these scaffolds in vitro for osteocompatibility with MC3T3 cells, and then tested the osseointegration and subsequent functional integration in vivo in a metaphyseal drill hole model in rat tibia. We found that PPP permits cell adhesion, growth, and mineralization in vitro. In vivo it was found that porous PPP significantly enhanced mineralization into the construct and increased the mechanical strength required to push out the scaffold in comparison to PEEK. This is the first study to investigate the performance of PPP as an orthopaedic biomaterial in vivo. PPP is an attractive material for orthopaedic implants due to the ease of manufacturing and superior mechanical strength.
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Affiliation(s)
- Hyunhee Ahn
- Department of Orthopaedics, Emory University, Atlanta, GA, USA; The Atlanta Veterans Affairs Medical Center Atlanta, Decatur, GA, USA
| | - Ravi R Patel
- Department of Mechanical Engineering, University of Colorado, Denver, CO, USA
| | - Anthony J Hoyt
- Department of Mechanical Engineering, University of Wyoming, Laramie, WY, USA
| | - Angela S P Lin
- George W. Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - F Brennan Torstrick
- George W. Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Robert E Guldberg
- George W. Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Carl P Frick
- Department of Mechanical Engineering, University of Wyoming, Laramie, WY, USA
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado, Denver, CO, USA
| | | | - Nick J Willett
- Department of Orthopaedics, Emory University, Atlanta, GA, USA; The Atlanta Veterans Affairs Medical Center Atlanta, Decatur, GA, USA.
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85
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Kelly CN, Miller AT, Hollister SJ, Guldberg RE, Gall K. Design and Structure-Function Characterization of 3D Printed Synthetic Porous Biomaterials for Tissue Engineering. Adv Healthc Mater 2018; 7:e1701095. [PMID: 29280325 DOI: 10.1002/adhm.201701095] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/19/2017] [Indexed: 12/18/2022]
Abstract
3D printing is now adopted for use in a variety of industries and functions. In biomedical engineering, 3D printing has prevailed over more traditional manufacturing methods in tissue engineering due to its high degree of control over both macro- and microarchitecture of porous tissue scaffolds. However, with the improved flexibility in design come new challenges in characterizing the structure-function relationships between various architectures and both mechanical and biological properties in an assortment of clinical applications. Presently, the field of tissue engineering lacks a comprehensive body of literature that is capable of drawing meaningful relationships between the designed structure and resulting function of 3D printed porous biomaterial scaffolds. This work first discusses the role of design on 3D printed porous scaffold function and then reviews characterization of these structure-function relationships for 3D printed synthetic metallic, polymeric, and ceramic biomaterials.
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Affiliation(s)
- Cambre N. Kelly
- Department of Mechanical Engineering and Materials Science; Duke University; Box 90300 Hudson Hall Durham NC 27708 USA
| | - Andrew T. Miller
- Department of Mechanical Engineering and Materials Science; Duke University; Box 90300 Hudson Hall Durham NC 27708 USA
| | - Scott J. Hollister
- Coulter Department of Biomedical Engineering; Georgia Institute of Technology; 313 Ferst Drive, Room 2127 Atlanta GA 30332 USA
| | - Robert E. Guldberg
- Parker H. Petit Institute for Bioengineering and Bioscience; Georgia Institute of Technology; 315 Ferst Drive Atlanta GA 30332 USA
| | - Ken Gall
- Department of Mechanical Engineering and Materials Science; Duke University; Box 90300 Hudson Hall Durham NC 27708 USA
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86
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Zhang J, Wei W, Yang L, Pan Y, Wang X, Wang T, Tang S, Yao Y, Hong H, Wei J. Stimulation of cell responses and bone ingrowth into macro-microporous implants of nano-bioglass/polyetheretherketone composite and enhanced antibacterial activity by release of hinokitiol. Colloids Surf B Biointerfaces 2018; 164:347-357. [PMID: 29413616 DOI: 10.1016/j.colsurfb.2018.01.058] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/22/2018] [Accepted: 01/28/2018] [Indexed: 12/17/2022]
Abstract
Poor osteogenesis and bacterial infection lead to the failure of implants, thus enhancements of osteogenic activity and antibacterial activity of the implants have significances in orthopedic applications. In this study, macro-microporous bone implants of nano-bioglass (nBG) and polyetheretherketone (PK) composite (mBPC) were fabricated. The results indicated that the mBPC with the porosity of around 70% exhibited interconnected macropores (sizes of about 400 μm) and micropores (sizes of about 10 μm). The apatite mineralization ability of mBPC in simulated body fluid (SBF) was significantly improved compared with macroporous nBG/PK composite (BPC) without micropores and macroporous PK (mPK). Drug of hinokitiol (HK) was loaded into mBPC (dmBPC), which displayed excellent in vitro antibacterial activity against Staphylococcus aureus. The MC3T3-E1 cells proliferation and ALP activity were significantly promoted by mBPC and dmBPC as compared with BPC and mPK. The micro-CT and histological evaluation showed that both mBPC and dmBPC containing nBG and micropores induced higher new bone formation into porous implants than mPK and BPC. The immunohistochemistry analysis indicated that the expression of BMP-2 in mBPC and dmBPC exhibited obviously higher level than mPK and BPC. The results suggested that the incorporation of nBG and micropores in mBPC obviously improved the osteogenic activity, and mBPC load with HK also promoted osteogenesis, indicating good biocompatibility. The dmBPC with HK significantly enhanced osteogenesis and antibacterial activity, which had great potential as bone implant for hard tissue repair.
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Affiliation(s)
- Jue Zhang
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China
| | - Wu Wei
- College of Materials Science & Engineering, Nanjing Tech. University, Nanjing, 210009, China
| | - Lili Yang
- Department of Orthopaedic Surgery, Changzheng Hospital, The Second Military Medical University, Shanghai, 200003, China
| | - Yongkang Pan
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China
| | - Xuehong Wang
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China
| | - Tinglan Wang
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China
| | - Songchao Tang
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China
| | - Yuan Yao
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China
| | - Hua Hong
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China.
| | - Jie Wei
- Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, 200237, Shanghai, China.
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87
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Hughes EAB, Parkes A, Williams RL, Jenkins MJ, Grover LM. Formulation of a covalently bonded hydroxyapatite and poly(ether ether ketone) composite. J Tissue Eng 2018; 9:2041731418815570. [PMID: 30574291 PMCID: PMC6299303 DOI: 10.1177/2041731418815570] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/31/2018] [Indexed: 01/21/2023] Open
Abstract
Spinal fusion devices can be fabricated from composites based on combining hydroxyapatite and poly(ether ether ketone) phases. These implants serve as load-bearing scaffolds for the formation of new bone tissue between adjacent vertebrae. In this work, we report a novel approach to covalently bond hydroxyapatite and poly(ether ether ketone) to produce a novel composite formulation with enhanced interfacial adhesion between phases. Compared to non-linked composites (HA_PEEK), covalently linked composites (HA_L_PEEK), loaded with 1.25 vol% hydroxyapatite, possessed a greater mean flexural strength (170 ± 5.4 vs 171.7 ± 14.8 MPa (mean ± SD)) and modulus (4.8 ± 0.2 vs 5.0 ± 0.3 GPa (mean ± SD)). Although the mechanical properties were not found to be significantly different (p > 0.05), PEEK_L_HA contained substantially larger hydroxyapatite inclusions (100-1000 µm) compared to HA_PEEK (50-200 µm), due to the inherently agglomerative nature of the covalently bonded hydroxyapatite and poly(ether ether ketone) additive. Larger inclusions would expectedly weaken the HA_L_PEEK composite; however, there is no significant difference between the flexural modulus of poly(ether ether ketone) with respect to HA_L_PEEK (p = 0.13). In addition, the flexural modulus of HA_PEEK is significantly lower compared to poly(ether ether ketone) (p = 0.03). Ultimately, covalent linking reduces hydroxyapatite particulate de-bonding from the polymeric matrix and inhibits micro-crack development, culminating in enhanced transfer of stiffness between hydroxyapatite and poly(ether ether ketone) under loading.
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Affiliation(s)
- Erik AB Hughes
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
- NIHR Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital, Birmingham, UK
| | - Andrew Parkes
- School of Metallurgy and Materials, University of Birmingham, Birmingham, UK
| | - Richard L Williams
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Mike J Jenkins
- School of Metallurgy and Materials, University of Birmingham, Birmingham, UK
| | - Liam M Grover
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
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88
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Chatham LS, Patel VV, Yakacki CM, Dana Carpenter R. Interbody Spacer Material Properties and Design Conformity for Reducing Subsidence During Lumbar Interbody Fusion. J Biomech Eng 2017; 139:2613838. [PMID: 28334320 DOI: 10.1115/1.4036312] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Indexed: 11/08/2022]
Abstract
There is a need to better understand the effects of intervertebral spacer material and design on the stress distribution in vertebral bodies and endplates to help reduce complications such as subsidence and improve outcomes following lumbar interbody fusion. The main objective of this study was to investigate the effects of spacer material on the stress and strain in the lumbar spine after interbody fusion with posterior instrumentation. A standard spacer was also compared with a custom-fit spacer, which conformed to the vertebral endplates, to determine if a custom fit would reduce stress on the endplates. A finite element (FE) model of the L4-L5 motion segment was developed from computed tomography (CT) images of a cadaveric lumbar spine. An interbody spacer, pedicle screws, and posterior rods were incorporated into the image-based model. The model was loaded in axial compression, and strain and stress were determined in the vertebra, spacer, and rods. Polyetheretherketone (PEEK), titanium, poly(para-phenylene) (PPP), and porous PPP (70% by volume) were used as the spacer material to quantify the effects on stress and strain in the system. Experimental testing of a cadaveric specimen was used to validate the model's results. There were no large differences in stress levels (<3%) at the bone-spacer interfaces and the rods when PEEK was used instead of titanium. Use of the porous PPP spacer produced an 8-15% decrease of stress at the bone-spacer interfaces and posterior rods. The custom-shaped spacer significantly decreased (>37%) the stress at the bone-spacer interfaces for all materials tested. A 28% decrease in stress was found in the posterior rods with the custom spacer. Of all the spacer materials tested with the custom spacer design, 70% porous PPP resulted in the lowest stress at the bone-spacer interfaces. The results show the potential for more compliant materials to reduce stress on the vertebral endplates postsurgery. The custom spacer provided a greater contact area between the spacer and bone, which distributed the stress more evenly, highlighting a possible strategy to decrease the risk of subsidence.
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Affiliation(s)
- Lillian S Chatham
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80204
| | - Vikas V Patel
- Department of Orthopaedic Surgery, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045
| | - Christopher M Yakacki
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80204
| | - R Dana Carpenter
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80204
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89
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Abstract
Interbody fusion cages are routinely implanted during spinal fusion procedures to facilitate arthrodesis of a degenerated or unstable vertebral segment. Current cages are most commonly made from polyether-ether-ketone (PEEK) due to its favorable mechanical properties and imaging characteristics. However, the smooth surface of current PEEK cages may limit implant osseointegration and may inhibit successful fusion. We present the development and clinical application of the first commercially available porous PEEK fusion cage (COHERE®, Vertera, Inc., Atlanta, GA) that aims to enhance PEEK osseointegration and spinal fusion outcomes. The porous PEEK structure is extruded directly from the underlying solid and mimics the structural and mechanical properties of trabecular bone to support bone ingrowth and implant fixation. Biomechanical testing of the COHERE® device has demonstrated greater expulsion resistance versus smooth PEEK cages with ridges and greater adhesion strength of porous PEEK versus plasma-sprayed titanium coated PEEK surfaces. In vitro experiments have shown favorable cell attachment to porous PEEK and greater proliferation and mineralization of cell cultures grown on porous PEEK versus smooth PEEK and smooth titanium surfaces, suggesting that the porous structure enhances bone formation at the cellular level. At the implant level, preclinical animal studies have found comparable bone ingrowth into porous PEEK as those previously reported for porous titanium, leading to twice the fixation strength of smooth PEEK implants. Finally, two clinical case studies are presented demonstrating the effectiveness of the COHERE® device in cervical spinal fusion.
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90
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Schwartz AM, Schenker ML, Ahn J, Willett NJ. Building better bone: The weaving of biologic and engineering strategies for managing bone loss. J Orthop Res 2017; 35:1855-1864. [PMID: 28467648 DOI: 10.1002/jor.23592] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 04/24/2017] [Indexed: 02/04/2023]
Abstract
Segmental bone loss remains a challenging clinical problem for orthopaedic trauma surgeons. In addition to the missing bone itself, the local tissues (soft tissue, vascular) are often highly traumatized as well, resulting in a less than ideal environment for bone regeneration. As a result, attempts at limb salvage become a highly expensive endeavor, often requiring multiple operations and necessitating the use of every available strategy (autograft, allograft, bone graft substitution, Masquelet, bone transport, etc.) to achieve bony union. A cost-sensitive, functionally appropriate, and volumetrically adequate engineered substitute would be practice-changing for orthopaedic trauma surgeons and these patients with difficult clinical problems. In tissue engineering and bone regeneration fields, numerous research efforts continue to make progress toward new therapeutic interventions for segmental bone loss, including novel biomaterial development as well as cell-based strategies. Despite an ever-evolving literature base of these new therapeutic and engineered options, there remains a disconnect with the clinical practice, with very few translating into clinical use. A symposium entitled "Building better bone: The weaving of biologic and engineering strategies for managing bone loss," was presented at the 2016 Orthopaedic Research Society Conference to further explore this engineering-clinical disconnect, by surveying basic, translational, and clinical researchers along with orthopaedic surgeons and proposing ideas for pushing the bar forward in the field of segmental bone loss. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1855-1864, 2017.
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Affiliation(s)
| | - Mara L Schenker
- Department of Orthopaedics, Emory University, Decatur, Georgia
| | - Jaimo Ahn
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nick J Willett
- Department of Orthopaedics, Emory University, Decatur, Georgia.,Atlanta Veteran's Affairs Medical Center, Decatur, Georgia.,Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia.,Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia
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91
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Miller AT, Safranski DL, Wood C, Guldberg RE, Gall K. Deformation and fatigue of tough 3D printed elastomer scaffolds processed by fused deposition modeling and continuous liquid interface production. J Mech Behav Biomed Mater 2017; 75:1-13. [PMID: 28689135 DOI: 10.1016/j.jmbbm.2017.06.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/27/2017] [Accepted: 06/30/2017] [Indexed: 12/16/2022]
Abstract
Polyurethane (PU) based elastomers continue to gain popularity in a variety of biomedical applications as compliant implant materials. In parallel, advancements in additive manufacturing continue to provide new opportunities for biomedical applications by enabling the creation of more complex architectures for tissue scaffolding and patient specific implants. The purpose of this study was to examine the effects of printed architecture on the monotonic and cyclic mechanical behavior of elastomeric PUs and to compare the structure-property relationship across two different printing approaches. We examined the tensile fatigue of notched specimens, 3D crosshatch scaffolds, and two 3D spherical pore architectures in a physically crosslinked polycarbonate urethane (PCU) printed via fused deposition modeling (FDM) as well as a photo-cured, chemically-crosslinked, elastomeric PU printed via continuous liquid interface production (CLIP). Both elastomers were relatively tolerant of 3D geometrical features as compared to stiffer synthetic implant materials such as PEEK and titanium. PCU and crosslinked PU samples with 3D porous structures demonstrated a reduced tensile failure stress as expected without a significant effect on tensile failure strain. PCU crosshatch samples demonstrated similar performance in strain-based tensile fatigue as solid controls; however, when plotted against stress amplitude and adjusted by porosity, it was clear that the architecture had an impact on performance. Square shaped notches or pores in crosslinked PU appeared to have a modest effect on strain-based tensile fatigue while circular shaped notches and pores had little impact relative to smooth samples. When plotted against stress amplitude, any differences in fatigue performance were small or not statistically significant for crosslinked PU samples. Despite the slight difference in local architecture and tolerances, crosslinked PU solid samples were found to perform on par with PCU solid samples in tensile fatigue, when appropriately adjusted for material hardness. Finally, tests of samples with printed architecture localized to the gage section revealed an effect in which fatigue performance appeared to drastically improve despite the localization of strain.
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Affiliation(s)
- Andrew T Miller
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, United States.
| | - David L Safranski
- MedShape, Inc., 1575 Northside Drive, NW, Suite 440, Atlanta, GA 30318, United States.
| | - Catherine Wood
- Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, NC 27708, United States.
| | - Robert E Guldberg
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, United States; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive, Atlanta, GA 30332, United States.
| | - Ken Gall
- Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, NC 27708, United States; MedShape, Inc., 1575 Northside Drive, NW, Suite 440, Atlanta, GA 30318, United States.
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92
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Liu X, Han F, Zhao P, Lin C, Wen X, Ye X. Layer-by-layer self-assembled multilayers on PEEK implants improve osseointegration in an osteoporosis rabbit model. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2017; 13:1423-1433. [PMID: 28131883 DOI: 10.1016/j.nano.2017.01.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 10/28/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
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93
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Youssef A, Hollister SJ, Dalton PD. Additive manufacturing of polymer melts for implantable medical devices and scaffolds. Biofabrication 2017; 9:012002. [DOI: 10.1088/1758-5090/aa5766] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Evans NT, Torstrick FB, Safranski DL, Guldberg RE, Gall K. Local deformation behavior of surface porous polyether-ether-ketone. J Mech Behav Biomed Mater 2017; 65:522-532. [DOI: 10.1016/j.jmbbm.2016.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/02/2016] [Accepted: 09/04/2016] [Indexed: 10/21/2022]
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95
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Cai L, Pan Y, Tang S, Li Q, Tang T, Zheng K, Boccaccini AR, Wei S, Wei J, Su J. Macro-mesoporous composites containing PEEK and mesoporous diopside as bone implants: characterization, in vitro mineralization, cytocompatibility, and vascularization potential and osteogenesis in vivo. J Mater Chem B 2017; 5:8337-8352. [PMID: 32264503 DOI: 10.1039/c7tb02344h] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Superior in vitro bioactivity, cytocompatibility, and in vivo osteogenesis and vascularization potential.
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96
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Mahjoubi H, Buck E, Manimunda P, Farivar R, Chromik R, Murshed M, Cerruti M. Surface phosphonation enhances hydroxyapatite coating adhesion on polyetheretherketone and its osseointegration potential. Acta Biomater 2017; 47:149-158. [PMID: 27717913 DOI: 10.1016/j.actbio.2016.10.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/28/2016] [Accepted: 10/03/2016] [Indexed: 12/19/2022]
Abstract
Polyetheretherketone (PEEK) has excellent mechanical properties, biocompatibility, chemical resistance and radiolucency, making it suitable for use as orthopedic implants. However, its surface is hydrophobic and bioinert, and surface modification is required to improve its bioactivity. In this work, we showed that grafting phosphonate groups via diazonium chemistry enhances the bioactivity of PEEK. Decreased contact angle indicated reduced hydrophobicity as a result of the treatment and X-ray photoelectron spectroscopy (XPS) confirmed the attachment of phosphonate groups to the surface. The surface treatment not only accelerated hydroxyapatite (HA) deposition after immersion in simulated body fluid but also significantly increased the adhesion strength of HA particles on PEEK. MC3T3-E1 cell viability, metabolic activity and deposition of calcium-containing minerals were also enhanced by the phosphonation. After three months of implantation in a critical size calvarial defect model, a fibrous capsule surrounded untreated PEEK while no fibrous capsule was observed around the treated PEEK. Instead, mineral deposition was observed in the region between the treated PEEK implant and underlying bone. This work introduces a simple method to improve the potential of PEEK-based orthopedic implants. STATEMENT OF SIGNIFICANCE We have introduced phosphonate groups on the surface of PEEK substrates using diazonium chemistry. Our results show that the treatment not only increased the adhesion strength of hydroxyapatite particles deposited on PEEK in vitro by approximately 40% compared to unmodified PEEK, but also improved the metabolic activity and mineralization of MC3T3-E1 cells. When implanted in cranial defects in rats, the phosphonate coating enhanced the osseointegration of PEEK by successfully preventing the formation of a fibrous capsule and favoring mineral deposition between the implant and the surrounding bone. This work introduces a simple method to improve the potential of PEEK-based orthopedic implants, particularly those with complex shapes.
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97
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Fracture characteristics of PEEK at various stress triaxialities. J Mech Behav Biomed Mater 2016; 64:173-86. [DOI: 10.1016/j.jmbbm.2016.07.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 07/16/2016] [Accepted: 07/21/2016] [Indexed: 11/19/2022]
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98
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Do Surface Porosity and Pore Size Influence Mechanical Properties and Cellular Response to PEEK? Clin Orthop Relat Res 2016; 474:2373-2383. [PMID: 27154533 PMCID: PMC5052186 DOI: 10.1007/s11999-016-4833-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Despite its widespread use in orthopaedic implants such as soft tissue fasteners and spinal intervertebral implants, polyetheretherketone (PEEK) often suffers from poor osseointegration. Introducing porosity can overcome this limitation by encouraging bone ingrowth; however, the corresponding decrease in implant strength can potentially reduce the implant's ability to bear physiologic loads. We have previously shown, using a single pore size, that limiting porosity to the surface of PEEK implants preserves strength while supporting in vivo osseointegration. However, additional work is needed to investigate the effect of pore size on both the mechanical properties and cellular response to PEEK. QUESTIONS/PURPOSES (1) Can surface porous PEEK (PEEK-SP) microstructure be reliably controlled? (2) What is the effect of pore size on the mechanical properties of PEEK-SP? (3) Do surface porosity and pore size influence the cellular response to PEEK? METHODS PEEK-SP was created by extruding PEEK through NaCl crystals of three controlled ranges: 200 to 312, 312 to 425, and 425 to 508 µm. Micro-CT was used to characterize the microstructure of PEEK-SP. Tensile, fatigue, and interfacial shear tests were performed to compare the mechanical properties of PEEK-SP with injection-molded PEEK (PEEK-IM). The cellular response to PEEK-SP, assessed by proliferation, alkaline phosphatase activity, vascular endothelial growth factor production, and calcium content of osteoblast, mesenchymal stem cell, and preosteoblast (MC3T3-E1) cultures, was compared with that of machined smooth PEEK and Ti6Al4V. RESULTS Micro-CT analysis showed that PEEK-SP layers possessed pores that were 284 ± 35 µm, 341 ± 49 µm, and 416 ± 54 µm for each pore size group. Porosity and pore layer depth ranged from 61% to 69% and 303 to 391 µm, respectively. Mechanical testing revealed tensile strengths > 67 MPa and interfacial shear strengths > 20 MPa for all three pore size groups. All PEEK-SP groups exhibited > 50% decrease in ductility compared with PEEK-IM and demonstrated fatigue strength > 38 MPa at one million cycles. All PEEK-SP groups also supported greater proliferation and cell-mediated mineralization compared with smooth PEEK and Ti6Al4V. CONCLUSIONS The PEEK-SP formulations evaluated in this study maintained favorable mechanical properties that merit further investigation into their use in load-bearing orthopaedic applications and supported greater in vitro osteogenic differentiation compared with smooth PEEK and Ti6Al4V. These results are independent of pore sizes ranging 200 µm to 508 µm. CLINICAL RELEVANCE PEEK-SP may provide enhanced osseointegration compared with current implants while maintaining the structural integrity to be considered for several load-bearing orthopaedic applications such as spinal fusion or soft tissue repair.
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Evaluating Osseointegration Into a Deeply Porous Titanium Scaffold: A Biomechanical Comparison With PEEK and Allograft. Spine (Phila Pa 1976) 2016; 41:E1146-E1150. [PMID: 27135643 DOI: 10.1097/brs.0000000000001672] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN This was a biomechanical push-out testing study using a porcine model. OBJECTIVE The purpose was to evaluate the strength of implant-bone interface of a porous titanium scaffold by comparing it to polyetheretherketone (PEEK) and allograft. SUMMARY OF BACKGROUND DATA Osseointegration is important for achieving maximal stability of spinal fusion implants and it is desirable to achieve as quickly as possible. Common PEEK interbody fusion implants appear to have limited osseointegration potential because of the formation of fibrous tissue along the implant-bone interface. Porous, three-dimensional titanium materials may be an option to enhance osseointegration. METHODS Using the skulls of two swine, in the region of the os frontale, 16 identical holes (4 mm diameter) were drilled to 10 mm depth in each skull. Porous titanium, PEEK, and allograft pins were press fit into the holes. After 5 weeks, animals were euthanized and the skull sections with the implants were cut into sections with each pin centered within a section. Push-out testing was performed using an MTS machine with a push rate of 6 mm/min. Load-deformation curves were used to compute the extrinsic material properties of the bone samples. Maximum force (N) and shear strength (MPa) were extracted from the output to record the bonding strength between the implant and surrounding bone. When calculating shear strength, maximum force was normalized by the actual implant surface area in contact with surrounding bone. RESULTS Mean push-out shear strength was significantly greater in the porous titanium scaffold group than in the PEEK or allograft groups (10.2 vs. 1.5 vs. 3.1 MPa, respectively; P < 0.05). CONCLUSION The push-out strength was significantly greater for the implants with porous titanium coating compared with the PEEK or allograft. These results suggest that the material has promise for facilitating osseointegration for implants, including interbody devices for spinal fusion. LEVEL OF EVIDENCE N/A.
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Impact of surface porosity and topography on the mechanical behavior of high strength biomedical polymers. J Mech Behav Biomed Mater 2016; 59:459-473. [DOI: 10.1016/j.jmbbm.2016.02.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 12/16/2022]
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