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Kolken H, de Jonge C, van der Sloten T, Garcia AF, Pouran B, Willemsen K, Weinans H, Zadpoor A. Additively manufactured space-filling meta-implants. Acta Biomater 2021; 125:345-357. [PMID: 33618018 DOI: 10.1016/j.actbio.2021.02.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/10/2021] [Accepted: 02/14/2021] [Indexed: 12/30/2022]
Abstract
The unprecedented properties of meta-biomaterials could pave the way for the development of life-lasting orthopedic implants. Here, we used non-auxetic meta-biomaterials to address the shortcomings of the current treatment options in acetabular revision surgery. Due to the severe bone deficiencies and poor bone quality, it can be very challenging to acquire adequate initial implant stability and long-term fixation. More advanced treatments, such as patient-specific implants, do guarantee the initial stability, but are formidably expensive and may eventually fail due to stress shielding. We, therefore, developed meta-implants furnished with a deformable porous outer layer. Upon implantation, this layer plastically deforms into the defects, thereby improving the initial stability and homogeneously stimulating the surrounding bone. We first studied the space-filling behavior of additively manufactured pure titanium lattices, based on six different unit cells, in a compression test complemented with full-field strain measurements. The diamond, body-centered cubic, and rhombic dodecahedron unit cells were eventually selected for the design of the deformable porous outer layer. Each design came in three different relative density profiles, namely maximum (MAX), functionally graded (FG), and minimum (MIN). After their compression in bone-mimicking molds with simulated acetabular defects, the space-filling behavior of the implants was evaluated using load-displacement curves, micro-CT images, and 3D reconstructions. The meta-implants with an FG diamond infill exhibited the most promising space-filling behavior. However, the required push-in forces exceed the impact forces currently applied in surgery. Future research should, therefore, focus on design optimization, to improve the space-filling behavior and to facilitate the implantation process for orthopedic surgeons. STATEMENT OF SIGNIFICANCE: Ideally, orthopedic implants would last for the entire lifetime of the patient. Unfortunately, they rarely do. Critically sized defects are a common sight in the revision of acetabular cups, and rather difficult to treat. The permanent deformation of lattice structures can be used to create shape-morphing implants that would fill up the defect site, and thereby restore the physiological loading conditions. Bending-dominated structures were incorporated in the porous outer layer of the space-filling meta-implants for their considerable lateral expansion in response to axial compression. A functionally graded density offered structural integrity at the joint while enhancing the deformability at the bone-implant interface. With the use of a more ductile metal, CP-Ti, these meta-implants could be deformed without strut failure.
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Mancini IAD, Schmidt S, Brommer H, Pouran B, Schäfer S, Tessmar J, Mensinga A, van Rijen MHP, Groll J, Blunk T, Levato R, Malda J, van Weeren PR. A composite hydrogel-3D printed thermoplast osteochondral anchor as example for a zonal approach to cartilage repair: in vivo performance in a long-term equine model. Biofabrication 2020; 12:035028. [PMID: 32434160 DOI: 10.1088/1758-5090/ab94ce] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent research has been focusing on the generation of living personalized osteochondral constructs for joint repair. Native articular cartilage has a zonal structure, which is not reflected in current constructs and which may be a cause of the frequent failure of these repair attempts. Therefore, we investigated the performance of a composite implant that further reflects the zonal distribution of cellular component both in vitro and in vivo in a long-term equine model. Constructs constituted of a 3D-printed poly(ϵ-caprolactone) (PCL) bone anchor from which reinforcing fibers protruded into the chondral part of the construct over which two layers of a thiol-ene cross-linkable hyaluronic acid/poly(glycidol) hybrid hydrogel (HA-SH/P(AGE-co-G)) were fabricated. The top layer contained Articular Cartilage Progenitor Cells (ACPCs) derived from the superficial layer of native cartilage tissue, the bottom layer contained mesenchymal stromal cells (MSCs). The chondral part of control constructs were homogeneously filled with MSCs. After six months in vivo, microtomography revealed significant bone growth into the anchor. Histologically, there was only limited production of cartilage-like tissue (despite persistency of hydrogel) both in zonal and non-zonal constructs. There were no differences in histological scoring; however, the repair tissue was significantly stiffer in defects repaired with zonal constructs. The sub-optimal quality of the repair tissue may be related to several factors, including early loss of implanted cells, or inappropriate degradation rate of the hydrogel. Nonetheless, this approach may be promising and research into further tailoring of biomaterials and of construct characteristics seems warranted.
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Affiliation(s)
- I A D Mancini
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM, Utrecht, The Netherlands. Regenerative Medicine Utrecht, Utrecht University, Utrecht, The Netherlands. Author to whom any correspondence should be addressed
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Boot W, Vogely HC, Jiao C, Nikkels PG, Pouran B, van Rijen MH, Ekkelenkamp MB, Hänsch GM, Dhert WJ, Gawlitta D. Prophylaxis of implant-related infections by local release of vancomycin from a hydrogel in rabbits. Eur Cell Mater 2020; 39:108-120. [PMID: 32072608 DOI: 10.22203/ecm.v039a07] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Local prophylaxis with antibiotic-loaded bone cement is a successful method to prevent post-operative infections in patients receiving orthopaedic implants. No comparable method is available for uncemented implants. Therefore, a hydrogel consisting of hyaluronic and polylactic acids was evaluated in a rabbit model for delivery of antimicrobial agents to prevent post-operative infections. In a pilot study, the suitability of the in vivo model was assessed by testing the hydrogel as carrier material for antimicrobial agents.In the main study, the antimicrobial-agent-loaded hydrogel was evaluated for infection prophylaxis. Rabbits received a titanium rod intramedullary in the tibia after contamination with Staphylococcus aureus. The rods were coated with unloaded hydrogel (Gel), hydrogel loaded with 2 % (Van2) or 5 % vancomycin (Van5), bioactive glass (BAG) or N-acetyl-L-cysteine (NAC). To analyse the infection severity after 28 d, histopathological, bacteriological, micro-computed tomographic and haematological analyses were performed. In the pilot study, the Van5 group had less infection (0/6 infected) as compared to the Gel group (5/5, p = 0.000) and the in vivo model was deemed suitable. In the main study, in the Van2 and Van5 groups, the number of infected animals was lower [1/6 (p = 0.006) and 2/6 (p = 0.044) infected, respectively]. In contrast, BAG and NAC groups showed no infection reduction (5/6 both groups, p = 0.997). The hydrogel can be used as a local carrier of vancomycin for prophylaxis of implant-related infections.The present study showed promising results for local delivery of antibacterial agents by hydrogel to prevent implant-related infections.
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Affiliation(s)
- W Boot
- UMC Utrecht, Heidelberglaan 100 3584 CX, Utrecht, the
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Li Y, Jahr H, Pavanram P, Bobbert F, Paggi U, Zhang XY, Pouran B, Leeflang M, Weinans H, Zhou J, Zadpoor A. Corrigendum to "Additively manufactured functionally graded biodegradable porous iron" [Acta Biomaterialia 96 (2019) 646-661]. Acta Biomater 2020; 101:646. [PMID: 31786087 DOI: 10.1016/j.actbio.2019.11.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Mancini IAD, Rieppo L, Pouran B, Afara IO, Braganca FMS, van Rijen MHP, Kik M, Weinans H, Toyras J, van Weeren PR, Malda J. Effects of body mass on microstructural features of the osteochondral unit: A comparative analysis of 37 mammalian species. Bone 2019; 127:664-673. [PMID: 31279095 DOI: 10.1016/j.bone.2019.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/28/2019] [Accepted: 07/02/2019] [Indexed: 01/26/2023]
Abstract
Since Galileo's days the effect of size on the anatomical characteristics of the structural elements of the body has been a subject of interest. However, the effects of scaling at tissue level have received little interest and virtually no data exist on the subject with respect to the osteochondral unit in the joint, despite this being one of the most lesion-prone and clinically relevant parts of the musculoskeletal system. Imaging techniques, including Fourier transform infrared imaging, polarized light microscopy and micro computed tomography, were combined to study the response to increasing body mass of the osteochondral unit. We analyzed the effect of scaling on structural characteristics of articular cartilage, subchondral plate and the supporting trabecular bone, across a wide range of mammals at microscopic level. We demonstrated that, while total cartilage thickness scales to body mass in a negative allometric fashion, thickness of different cartilage layers did not. Cartilage tissue layers were found to adapt to increasing loads principally in the deep zone with the superficial layers becoming relatively thinner. Subchondral plate thickness was found to have no correlation to body mass, nor did bone volume fraction. The underlying trabecular bone was found to have thicker trabeculae (r=0.75, p<0.001), as expected since this structure carries most loads and plays a role in force mitigation. The results of this study suggest that the osteochondral tissue structure has remained remarkably preserved across mammalian species during evolution, and that in particular, the trabecular bone carries the adaptation to the increasing body mass.
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Affiliation(s)
- I A D Mancini
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands; Regenerative Medicine Utrecht, Utrecht University, Utrecht, the Netherlands
| | - L Rieppo
- Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - B Pouran
- Regenerative Medicine Utrecht, Utrecht University, Utrecht, the Netherlands; Department of Orthopedics, University Medical Centre Utrecht, Utrecht, the Netherlands; Department of Biomechanical Engineering, TU, Delft, the Netherlands
| | - I O Afara
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - F M Serra Braganca
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands
| | - M H P van Rijen
- Regenerative Medicine Utrecht, Utrecht University, Utrecht, the Netherlands; Department of Orthopedics, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - M Kik
- Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, the Netherlands
| | - H Weinans
- Regenerative Medicine Utrecht, Utrecht University, Utrecht, the Netherlands; Department of Orthopedics, University Medical Centre Utrecht, Utrecht, the Netherlands; Department of Biomechanical Engineering, TU, Delft, the Netherlands
| | - J Toyras
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Diagnostic Imaging Centre, Kuopio University Hospital, Kuopio, Finland; School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia
| | - P R van Weeren
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands; Regenerative Medicine Utrecht, Utrecht University, Utrecht, the Netherlands
| | - J Malda
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands; Regenerative Medicine Utrecht, Utrecht University, Utrecht, the Netherlands; Department of Orthopedics, University Medical Centre Utrecht, Utrecht, the Netherlands.
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Li Y, Jahr H, Pavanram P, Bobbert FSL, Paggi U, Zhang XY, Pouran B, Leeflang MA, Weinans H, Zhou J, Zadpoor AA. Additively manufactured functionally graded biodegradable porous iron. Acta Biomater 2019; 96:646-661. [PMID: 31302295 DOI: 10.1016/j.actbio.2019.07.013] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/03/2019] [Accepted: 07/09/2019] [Indexed: 11/28/2022]
Abstract
Additively manufactured (AM) functionally graded porous metallic biomaterials offer unique opportunities to satisfy the contradictory design requirements of an ideal bone substitute. However, no functionally graded porous structures have ever been 3D-printed from biodegradable metals, even though biodegradability is crucial both for full tissue regeneration and for the prevention of implant-associated infections in the long term. Here, we present the first ever report on AM functionally graded biodegradable porous metallic biomaterials. We made use of a diamond unit cell for the topological design of four different types of porous structures including two functionally graded structures and two reference uniform structures. Specimens were then fabricated from pure iron powder using selective laser melting (SLM), followed by experimental and computational analyses of their permeability, dynamic biodegradation behavior, mechanical properties, and cytocompatibility. It was found that the topological design with functional gradients controlled the fluid flow, mass transport properties and biodegradation behavior of the AM porous iron specimens, as up to 4-fold variations in permeability and up to 3-fold variations in biodegradation rate were observed for the different experimental groups. After 4 weeks of in vitro biodegradation, the AM porous scaffolds lost 5-16% of their weight. This falls into the desired range of biodegradation rates for bone substitution and confirms our hypothesis that topological design could indeed accelerate the biodegradation of otherwise slowly degrading metals, like iron. Even after 4 weeks of biodegradation, the mechanical properties of the specimens (i.e., E = 0.5-2.1 GPa, σy = 8-48 MPa) remained within the range of the values reported for trabecular bone. Design-dependent cell viability did not differ from gold standard controls for up to 48 h. This study clearly shows the great potential of AM functionally graded porous iron as a bone substituting material. Moreover, we demonstrate that complex topological design permits the control of mechanical properties, degradation behavior of AM porous metallic biomaterials. STATEMENT OF SIGNIFICANCE: No functionally graded porous structures have ever been 3D-printed from biodegradable metals, even though biodegradability is crucial both for full tissue regeneration and for the prevention of implant-associated infections in the long term. Here, we present the first report on 3D-printed functionally graded biodegradable porous metallic biomaterials. Our results suggest that topological design in general, and functional gradients in particular can be used as an important tool for adjusting the biodegradation behavior of AM porous metallic biomaterials. The biodegradation rate and mass transport properties of AM porous iron can be increased while maintaining the bone-mimicking mechanical properties of these biomaterials. The observations reported here underline the importance of proper topological design in the development of AM porous biodegradable metals.
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Affiliation(s)
- Y Li
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands.
| | - H Jahr
- Department of Anatomy and Cell Biology, University Hospital RWTH Aachen, Aachen 52074, Germany; Department of Orthopedic Surgery, Maastricht UMC+, Maastricht 6202 AZ, The Netherlands
| | - P Pavanram
- Department of Anatomy and Cell Biology, University Hospital RWTH Aachen, Aachen 52074, Germany
| | - F S L Bobbert
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - U Paggi
- 3D Systems - LayerWise NV, Grauwmeer 14, Leuven 3001, Belgium; KU Leuven Department of Mechanical Engineering, Kasteelpark Arenberg 44, Leuven 3001, Belgium
| | - X-Y Zhang
- Department of Mechanical Engineering, Tsinghua University, Beijing 10004, China
| | - B Pouran
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands; Department of Orthopedics, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands
| | - M A Leeflang
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - H Weinans
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands; Department of Orthopedics, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands
| | - J Zhou
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - A A Zadpoor
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
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Croes M, Kruyt MC, Boot W, Pouran B, Braham MV, Pakpahan SA, Weinans H, Vogely HC, Fluit AC, Dhert WJ, Alblas J, Öner FC. The role of bacterial stimuli in inflammation-driven bone formation. Eur Cell Mater 2019; 37:402-419. [PMID: 31094449 DOI: 10.22203/ecm.v037a24] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Immune cells and their soluble factors regulate skeletal cells during normal bone regeneration and pathological bone formation. Bacterial infections can trigger immune responses that activate pro-osteogenic pathways, but these are usually overshadowed by osteolysis and concerns of systemic inflammation. The aim of this study was to determine whether the transient local inflammatory reaction to non-viable bacterial immune agonists could lead to favourable new bone formation. In a series of rabbit studies, as proof-of-concept, how tibial intramedullary injection of viable or killed bacterial species affected bone remodelling and new bone formation was determined. Application of killed bacteria led to considerable new bone formation after 4 weeks, without the prolonged systemic inflammation and exaggerated bone lysis seen with active infection. The osteo-immunomodulatory effects of various species of killed bacteria and the dose response relationship were subsequently screened in ectopically-implanted ceramic scaffolds. Histomorphometry after 8 weeks showed that a relatively low dose of killed bacteria enhanced ectopic bone induction. Moreover, lipoteichoic acid - the bacterial cell-wall derived toll-like-receptor (TLR)-2 activator - was identified as an osteo-stimulatory factor. Collectively, the data indicated that bacterial stimuli could be harnessed to stimulate osteogenesis, which occurs through a synergy with osteoinductive signals. This finding holds promise for the use of non-viable bacteria, bacterial antigens, or their simplified analogues as immuno-modulatory bone regenerating tools in bone biomaterials.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - J Alblas
- Department of Orthopaedics University Medical Centre Utrecht, Rm G05.228, P.O. Box 85500, Utrecht 3508 GA, the Netherlands. j.alblas @umcutrecht.nl
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Tellegen AR, Rudnik-Jansen I, Pouran B, de Visser HM, Weinans HH, Thomas RE, Kik MJL, Grinwis GCM, Thies JC, Woike N, Mihov G, Emans PJ, Meij BP, Creemers LB, Tryfonidou MA. Controlled release of celecoxib inhibits inflammation, bone cysts and osteophyte formation in a preclinical model of osteoarthritis. Drug Deliv 2018; 25:1438-1447. [PMID: 29890922 PMCID: PMC6058666 DOI: 10.1080/10717544.2018.1482971] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Major hallmarks of osteoarthritis (OA) are cartilage degeneration, inflammation and osteophyte formation. COX-2 inhibitors counteract inflammation-related pain, but their prolonged oral use entails the risk for side effects. Local and prolonged administration in biocompatible and degradable drug delivery biomaterials could offer an efficient and safe treatment for the long-term management of OA symptoms. Therefore, we evaluated the disease-modifying effects and the optimal dose of polyesteramide microspheres delivering the COX-2 inhibitor celecoxib in a rat OA model. Four weeks after OA induction by anterior cruciate ligament transection and partial medial meniscectomy, 8-week-old female rats (n = 6/group) were injected intra-articular with celecoxib-loaded microspheres at three dosages (0.03, 0.23 or 0.39 mg). Unloaded microspheres served as control. During the 16-week follow-up, static weight bearing and plasma celecoxib concentrations were monitored. Post-mortem, micro-computed tomography and knee joint histology determined progression of synovitis, osteophyte formation, subchondral bone changes, and cartilage integrity. Systemic celecoxib levels were below the detection limit 6 days upon delivery. Systemic and local adverse effects were absent. Local delivery of celecoxib reduced the formation of osteophytes, subchondral sclerosis, bone cysts and calcified loose bodies, and reduced synovial inflammation, while cartilage histology was unaffected. Even though the effects on pain could not be evualated directly in the current model, our results suggest the application of celecoxib-loaded microspheres holds promise as novel, safe and effective treatment for inflammation and pain in OA.
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Affiliation(s)
- A R Tellegen
- a Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands
| | - I Rudnik-Jansen
- b Department of Orthopaedics , University Medical Centre Utrecht , Utrecht , The Netherlands
| | - B Pouran
- c Department of Rheumatology and Clinical Immunology , University Medical Centre Utrecht , Utrecht , The Netherlands
| | - H M de Visser
- c Department of Rheumatology and Clinical Immunology , University Medical Centre Utrecht , Utrecht , The Netherlands
| | - H H Weinans
- b Department of Orthopaedics , University Medical Centre Utrecht , Utrecht , The Netherlands.,c Department of Rheumatology and Clinical Immunology , University Medical Centre Utrecht , Utrecht , The Netherlands
| | - R E Thomas
- d Department of Pathobiology, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands
| | - M J L Kik
- d Department of Pathobiology, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands
| | - G C M Grinwis
- d Department of Pathobiology, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands
| | - J C Thies
- e DSM Biomedical , Geleen , the Netherlands
| | - N Woike
- e DSM Biomedical , Geleen , the Netherlands
| | - G Mihov
- e DSM Biomedical , Geleen , the Netherlands
| | - P J Emans
- f Department of Orthopaedics , University Medical Centre Maastricht , Maastricht , The Netherlands
| | - B P Meij
- a Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands
| | - L B Creemers
- b Department of Orthopaedics , University Medical Centre Utrecht , Utrecht , The Netherlands
| | - M A Tryfonidou
- a Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands
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Li Y, Jahr H, Lietaert K, Pavanram P, Yilmaz A, Fockaert LI, Leeflang MA, Pouran B, Gonzalez-Garcia Y, Weinans H, Mol JMC, Zhou J, Zadpoor AA. Additively manufactured biodegradable porous iron. Acta Biomater 2018; 77:380-393. [PMID: 29981948 DOI: 10.1016/j.actbio.2018.07.011] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/14/2018] [Accepted: 07/05/2018] [Indexed: 01/14/2023]
Abstract
Additively manufactured (AM) topologically ordered porous metallic biomaterials with the proper biodegradation profile offer a unique combination of properties ideal for bone regeneration. These include a fully interconnected porous structure, bone-mimicking mechanical properties, and the possibility of fully regenerating bony defects. Most of such biomaterials are, however, based on magnesium and, thus, degrade too fast. Here, we present the first report on topologically ordered porous iron made by Direct Metal Printing (DMP). The topological design was based on a repetitive diamond unit cell. We conducted a comprehensive study on the in vitro biodegradation behavior (up to 28 days), electrochemical performance, time-dependent mechanical properties, and biocompatibility of the scaffolds. The mechanical properties of AM porous iron (E = 1600-1800 MPa) were still within the range of the values reported for trabecular bone after 28 days of biodegradation. Electrochemical tests showed up to ≈12 times higher rates of biodegradation for AM porous iron as compared to that of cold-rolled (CR) iron, while only 3.1% of weight loss was measured after 4 weeks of immersion tests. The biodegradation mechanisms were found to be topology-dependent and different between the periphery and central parts of the scaffolds. While direct contact between MG-63 cells and scaffolds revealed substantial and almost instant cytotoxicity in static cell culture, as compared to Ti-6Al-4V, the cytocompatibility according to ISO 10993 was reasonable in in vitro assays for up to 72 h. This study shows how DMP could be used to increase the surface area and decrease the grain sizes of topologically ordered porous metallic biomaterials made from metals that are usually considered to degrade too slowly (e.g., iron), opening up many new opportunities for the development of biodegradable metallic biomaterials. STATEMENT OF SIGNIFICANCE Biodegradation in general and proper biodegradation profile in particular are perhaps the most important requirements that additively manufactured (AM) topologically ordered porous metallic biomaterials should offer in order to become the ideal biomaterial for bone regeneration. Currently, most biodegradable metallic biomaterials are based on magnesium, which degrade fast with gas generation. Here, we present the first report on topologically ordered porous iron made by Direct Metal Printing (DMP). We also conducted a comprehensive study on the biodegradation behavior, electrochemical performance, biocompatibility, and the time evolution of the mechanical properties of the implants. We show that these implants possess bone-mimicking mechanical properties, accelerated degradation rate, and reasonable cytocompatibility, opening up many new opportunities for the development of iron-based biodegradable materials.
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Affiliation(s)
- Y Li
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands.
| | - H Jahr
- Department of Anatomy and Cell Biology, University Hospital RWTH Aachen, Aachen 52074, Germany; Department of Orthopedic Surgery, Maastricht UMC+, Maastricht 6202 AZ, The Netherlands
| | - K Lietaert
- 3D Systems - LayerWise NV, Grauwmeer 14, Leuven 3001, Belgium; KU Leuven Department of Materials Engineering, Kasteelpark Arenberg 44, Leuven 3001, Belgium
| | - P Pavanram
- Department of Anatomy and Cell Biology, University Hospital RWTH Aachen, Aachen 52074, Germany
| | - A Yilmaz
- Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - L I Fockaert
- Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - M A Leeflang
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - B Pouran
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands; Department of Orthopedics, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands
| | - Y Gonzalez-Garcia
- Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - H Weinans
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands; Department of Orthopedics, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands; Department of Rheumatology, University Medical Center Utrecht, Utrecht 3584CX, The Netherlands
| | - J M C Mol
- Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - J Zhou
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - A A Zadpoor
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
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Horeman T, Buiter EC, Pouran B, Stijntjes M, Dankelman J, Tuijthof GJM. In-Vitro Detection of Small Isolated Cartilage Defects: Intravascular Ultrasound Vs. Optical Coherence Tomography. Ann Biomed Eng 2018; 46:1745-1755. [PMID: 29946970 PMCID: PMC6208880 DOI: 10.1007/s10439-018-2073-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/08/2018] [Indexed: 12/20/2022]
Abstract
This experimental work focused on the sensor selection for the development of a needle-like instrument to treat small isolated cartilage defects with hydrogels. The aim was to identify the most accurate and sensitive imaging method to determine the location and size of defects compared to a gold standard (µCT). Only intravascular ultrasound imaging (IVUS) vs. optical coherent tomography (OCT) were looked at, as they fulfilled the criteria for integration in the needle design. An in-vitro study was conducted on six human cadaveric tali that were dissected and submerged in saline. To simulate the natural appearance of cartilage defects, three types of defects were created via a standardised protocol: osteochondral defects (OCD), chondral defects (CD) and cartilage surface fibrillation (CSF), all sized between 0.1 and 3 mm in diameter. The detection rate by two observers for all diameters of OCD were 80, 92 and 100% with IVUS, OCT and µCT, for CD these were 60, 83 and 97%, and for CSF 0, 29 and 24%. Both IVUS and OCT can detect the presence of OCD and CD accurately if they are larger than 2 mm in diameter, and OCT can detect fibrillated cartilage defects larger than 3 mm in diameter. A significant difference between OCT–µCT and IVUS–µCT was found for the diameter error (p = 0.004) and insertion depth error (p = 0.002), indicating that OCT gives values closer to reference µCT. The OCT imaging technique is more sensitive to various types and sizes of defects and has a smaller diameter, and is therefore preferred for the intended application.
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Affiliation(s)
- T Horeman
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands. .,Department of Orthopedic Surgery, Academic Centre for Evidence-based Sports Medicine (ACES), Academic Medical Centre, Amsterdam, The Netherlands.
| | - E C Buiter
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - B Pouran
- Department of Orthopaedics, UMC Utrecht Regenerative Medicine Centre, Utrecht, The Netherlands
| | - M Stijntjes
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - J Dankelman
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - G J M Tuijthof
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands.,Department of Orthopedic Surgery, Academic Centre for Evidence-based Sports Medicine (ACES), Academic Medical Centre, Amsterdam, The Netherlands.,Research Centre Smart Devices, Zuyd University of Applied Sciences, Heerlen, The Netherlands
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Hedayati R, Ahmadi S, Lietaert K, Pouran B, Li Y, Weinans H, Rans C, Zadpoor A. Isolated and modulated effects of topology and material type on the mechanical properties of additively manufactured porous biomaterials. J Mech Behav Biomed Mater 2018; 79:254-263. [DOI: 10.1016/j.jmbbm.2017.12.029] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 12/22/2017] [Accepted: 12/28/2017] [Indexed: 11/29/2022]
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Li Y, Zhou J, Pavanram P, Leeflang M, Fockaert L, Pouran B, Tümer N, Schröder KU, Mol J, Weinans H, Jahr H, Zadpoor A. Additively manufactured biodegradable porous magnesium. Acta Biomater 2018; 67:378-392. [PMID: 29242158 DOI: 10.1016/j.actbio.2017.12.008] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 01/11/2023]
Abstract
An ideal bone substituting material should be bone-mimicking in terms of mechanical properties, present a precisely controlled and fully interconnected porous structure, and degrade in the human body to allow for full regeneration of large bony defects. However, simultaneously satisfying all these three requirements has so far been highly challenging. Here we present topologically ordered porous magnesium (WE43) scaffolds based on the diamond unit cell that were fabricated by selective laser melting (SLM) and satisfy all the requirements. We studied the in vitro biodegradation behavior (up to 4 weeks), mechanical properties and biocompatibility of the developed scaffolds. The mechanical properties of the AM porous WE43 (E = 700-800 MPa) scaffolds were found to fall into the range of the values reported for trabecular bone even after 4 weeks of biodegradation. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), electrochemical tests and µCT revealed a unique biodegradation mechanism that started with uniform corrosion, followed by localized corrosion, particularly in the center of the scaffolds. Biocompatibility tests performed up to 72 h showed level 0 cytotoxicity (according to ISO 10993-5 and -12), except for one time point (i.e., 24 h). Intimate contact between cells (MG-63) and the scaffolds was also observed in SEM images. The study shows for the first time that AM of porous Mg may provide distinct possibilities to adjust biodegradation profile through topological design and open up unprecedented opportunities to develop multifunctional bone substituting materials that mimic bone properties and enable full regeneration of critical-size load-bearing bony defects. STATEMENT OF SIGNIFICANCE The ideal biomaterials for bone tissue regeneration should be bone-mimicking in terms of mechanical properties, present a fully interconnected porous structure, and exhibit a specific biodegradation behavior to enable full regeneration of bony defects. Recent advances in additive manufacturing have resulted in biomaterials that satisfy the first two requirements but simultaneously satisfying the third requirement has proven challenging so far. Here we present additively manufactured porous magnesium structures that have the potential to satisfy all above-mentioned requirements. Even after 4 weeks of biodegradation, the mechanical properties of the porous structures were found to be within those reported for native bone. Moreover, our comprehensive electrochemical, mechanical, topological, and biological study revealed a unique biodegradation behavior and the limited cytotoxicity of the developed biomaterials.
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Ahmadi S, Hedayati R, Li Y, Lietaert K, Tümer N, Fatemi A, Rans C, Pouran B, Weinans H, Zadpoor A. Fatigue performance of additively manufactured meta-biomaterials: The effects of topology and material type. Acta Biomater 2018; 65:292-304. [PMID: 29127065 DOI: 10.1016/j.actbio.2017.11.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 01/13/2023]
Abstract
Additive manufacturing (AM) techniques enable fabrication of bone-mimicking meta-biomaterials with unprecedented combinations of topological, mechanical, and mass transport properties. The mechanical performance of AM meta-biomaterials is a direct function of their topological design. It is, however, not clear to what extent the material type is important in determining the fatigue behavior of such biomaterials. We therefore aimed to determine the isolated and modulated effects of topological design and material type on the fatigue response of metallic meta-biomaterials fabricated with selective laser melting. Towards that end, we designed and additively manufactured Co-Cr meta-biomaterials with three types of repeating unit cells and three to four porosities per type of repeating unit cell. The AM meta-biomaterials were then mechanically tested to obtain their normalized S-N curves. The obtained S-N curves of Co-Cr meta-biomaterials were compared to those of meta-biomaterials with same topological designs but made from other materials, i.e. Ti-6Al-4V, tantalum, and pure titanium, available from our previous studies. We found the material type to be far more important than the topological design in determining the normalized fatigue strength of our AM metallic meta-biomaterials. This is the opposite of what we have found for the quasi-static mechanical properties of the same meta-biomaterials. The effects of material type, manufacturing imperfections, and topological design were different in the high and low cycle fatigue regions. That is likely because the cyclic response of meta-biomaterials depends not only on the static and fatigue strengths of the bulk material but also on other factors that may include strut roughness, distribution of the micro-pores created inside the struts during the AM process, and plasticity. STATEMENT OF SIGNIFICANCE Meta-biomaterials are a special class of metamaterials with unusual or unprecedented combinations of mechanical, physical (e.g. mass transport), and biological properties. Topologically complex and additively manufactured meta-biomaterials have been shown to improve bone regeneration and osseointegration. The mechanical properties of such biomaterials are directly related to their topological design and material type. However, previous studies of such biomaterials have largely neglected the effects of material type, instead focusing on topological design. We show here that neglecting the effects of material type is unjustified. We studied the isolated and combined effects of topological design and material type on the normalized S-N curves of metallic bone-mimicking biomaterials and found them to be more strongly dependent on the material type than topological design.
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Boot W, Gawlitta D, Nikkels PGJ, Pouran B, van Rijen MHP, Dhert WJA, Vogely HC. Hyaluronic Acid-Based Hydrogel Coating Does Not Affect Bone Apposition at the Implant Surface in a Rabbit Model. Clin Orthop Relat Res 2017; 475:1911-1919. [PMID: 28303535 PMCID: PMC5449332 DOI: 10.1007/s11999-017-5310-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 02/28/2017] [Indexed: 01/31/2023]
Abstract
BACKGROUND Uncemented orthopaedic implants rely on the bone-implant interface to provide stability, therefore it is essential that a coating does not interfere with the bone-forming processes occurring at the implant interface. In addition, local application of high concentrations of antibiotics for prophylaxis or treatment of infection may be toxic for osteoblasts and could impair bone growth. QUESTIONS/PURPOSES In this animal study, we investigated the effect of a commercially available hydrogel, either unloaded or loaded with 2% vancomycin. We asked, does unloaded hydrogel or hydrogel with vancomycin (1) interfere with bone apposition and timing of bone deposition near the implant surface; and (2) induce a local or systemic inflammatory reaction as determined by inflammation around the implant and hematologic parameters. METHODS In 18 New Zealand White rabbits, an uncoated titanium rod (n = 6), a rod coated with unloaded hydrogel (n = 6), or a rod coated with 2% vancomycin-loaded hydrogel (n = 6) was implanted in the intramedullary canal of the left tibia. After 28 days, the bone volume fraction near the implant was measured with microCT analysis, inflammation was semiquantitatively scored on histologic sections, and timing of bone apposition was followed by semiquantitative scoring of fluorochrome incorporation on histologic sections. Two observers, blinded to the treatment, scored the sections and reconciled their scores if there was a disagreement. The hematologic inflammatory reaction was analyzed by measuring total and differential leukocyte counts and erythrocyte sedimentation rates in blood. With group sizes of six animals per group, we had 79% power to detect a difference of 25% in histologic scoring for infection and inflammation. RESULTS No differences were found in the amount of bone apposition near the implant in the No Gel group (48.65% ± 14.95%) compared with the Gel group (59.97% ± 5.02%; mean difference [MD], 11.32%; 95% CI, -3.89% to 26.53%; p = 0.16) or for the Van2 group (56.12% ± 10.06%; MD, 7.46; 95% CI, -7.75 to 22.67; p = 0.40), with the numbers available. In addition, the scores for timing of bone apposition did not differ between the No Gel group (0.50 ± 0.55) compared with the Gel group (0.33 ± 0.52; MD, -0.17; 95% CI, -0.86 to 0.53; p = 0.78) or the Van2 group (0.83 ± 0.41; MD, 0.33; 95% CI, -0.36 to 1.03; p = 0.42). Furthermore, we detected no differences in the histopathology scores for inflammation in the No Gel group (2.33 ± 1.67) compared with the Gel group (3.17 ± 1.59; MD, 0.83; 95% CI, -0.59 to 2.26; p = 0.31) or to the Van2 group (2.5 ± 1.24; MD, 0.17; 95% CI, -1.26 to 1.59; p = 0.95). Moreover, no differences in total leukocyte count, erythrocyte sedimentation rate, and neutrophil, monocyte, eosinophil, basophil, and lymphocyte counts were present between the No Gel or Van2 groups compared with the Gel control group, with the numbers available. CONCLUSION The hydrogel coated on titanium implants, unloaded or loaded with 2% vancomycin, had no effect on the volume or timing of bone apposition near the implant, and did not induce an inflammatory reaction in vivo, with the numbers available. CLINICAL RELEVANCE Antibiotic-loaded hydrogel may prove to be a valuable option to protect orthopaedic implants from bacterial colonization. Future clinical safety studies will need to provide more evidence that this product does not impair bone formation near the implant and prove the safety of this product.
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Affiliation(s)
- W. Boot
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - D. Gawlitta
- Department of Oral and Maxillofacial Surgery & Special Dental Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - P. G. J. Nikkels
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - B. Pouran
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M. H. P. van Rijen
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - W. J. A. Dhert
- Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - H. Ch. Vogely
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
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Harteveld AA, Denswil NP, Siero JCW, Zwanenburg JJM, Vink A, Pouran B, Spliet WGM, Klomp DWJ, Luijten PR, Daemen MJ, Hendrikse J, van der Kolk AG. Quantitative Intracranial Atherosclerotic Plaque Characterization at 7T MRI: An Ex Vivo Study with Histologic Validation. AJNR Am J Neuroradiol 2016; 37:802-10. [PMID: 26705320 DOI: 10.3174/ajnr.a4628] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/27/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND PURPOSE In recent years, several high-resolution vessel wall MR imaging techniques have emerged for the characterization of intracranial atherosclerotic vessel wall lesions in vivo. However, a thorough validation of MR imaging results of intracranial plaques with histopathology is still lacking. The aim of this study was to characterize atherosclerotic plaque components in a quantitative manner by obtaining the MR signal characteristics (T1, T2, T2*, and proton density) at 7T in ex vivo circle of Willis specimens and using histopathology for validation. MATERIALS AND METHODS A multiparametric ultra-high-resolution quantitative MR imaging protocol was performed at 7T to identify the MR signal characteristics of different intracranial atherosclerotic plaque components, and using histopathology for validation. In total, 38 advanced plaques were matched between MR imaging and histology, and ROI analysis was performed on the identified tissue components. RESULTS Mean T1, T2, and T2* relaxation times and proton density values were significantly different between different tissue components. The quantitative T1 map showed the most differences among individual tissue components of intracranial plaques with significant differences in T1 values between lipid accumulation (T1 = 838 ± 167 ms), fibrous tissue (T1 = 583 ± 161 ms), fibrous cap (T1 = 481 ± 98 ms), calcifications (T1 = 314 ± 39 ms), and the intracranial arterial vessel wall (T1 = 436 ± 122 ms). CONCLUSIONS Different tissue components of advanced intracranial plaques have distinguishable imaging characteristics with ultra-high-resolution quantitative MR imaging at 7T. Based on this study, the most promising method for distinguishing intracranial plaque components is T1-weighted imaging.
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Affiliation(s)
- A A Harteveld
- From the Departments of Radiology (A.A.H., J.C.W.S., J.J.M.Z., D.W.J.K., P.R.L., J.H., A.G.v.d.K.)
| | - N P Denswil
- Department of Pathology (N.P.D., M.J.D.), Academic Medical Center, Amsterdam, the Netherlands
| | - J C W Siero
- From the Departments of Radiology (A.A.H., J.C.W.S., J.J.M.Z., D.W.J.K., P.R.L., J.H., A.G.v.d.K.)
| | - J J M Zwanenburg
- From the Departments of Radiology (A.A.H., J.C.W.S., J.J.M.Z., D.W.J.K., P.R.L., J.H., A.G.v.d.K.) Image Sciences Institute (J.J.M.Z.), University Medical Center Utrecht, Utrecht, the Netherlands
| | - A Vink
- Pathology (A.V., W.G.M.S.)
| | - B Pouran
- Orthopedics (B.P.) Rheumatology (B.P.) Department of Biomedical Engineering (B.P.), Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Delft, the Netherlands
| | | | - D W J Klomp
- From the Departments of Radiology (A.A.H., J.C.W.S., J.J.M.Z., D.W.J.K., P.R.L., J.H., A.G.v.d.K.)
| | - P R Luijten
- From the Departments of Radiology (A.A.H., J.C.W.S., J.J.M.Z., D.W.J.K., P.R.L., J.H., A.G.v.d.K.)
| | - M J Daemen
- Department of Pathology (N.P.D., M.J.D.), Academic Medical Center, Amsterdam, the Netherlands
| | - J Hendrikse
- From the Departments of Radiology (A.A.H., J.C.W.S., J.J.M.Z., D.W.J.K., P.R.L., J.H., A.G.v.d.K.)
| | - A G van der Kolk
- From the Departments of Radiology (A.A.H., J.C.W.S., J.J.M.Z., D.W.J.K., P.R.L., J.H., A.G.v.d.K.)
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Moshtagh PR, Pouran B, van Tiel J, Rauker J, Zuiddam MR, Arbabi V, Korthagen NM, Weinans H, Zadpoor AA. Micro- and nano-mechanics of osteoarthritic cartilage: The effects of tonicity and disease severity. J Mech Behav Biomed Mater 2016; 59:561-571. [PMID: 27043052 DOI: 10.1016/j.jmbbm.2016.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/23/2016] [Accepted: 03/09/2016] [Indexed: 10/22/2022]
Abstract
The present study aims to discover the contribution of glycosaminoglycans (GAGs) and collagen fibers to the mechanical properties of the osteoarthritic (OA) cartilage tissue. We used nanoindentation experiments to understand the mechanical behavior of mild and severe osteoarthritic cartilage at micro- and nano-scale at different swelling conditions. Contrast enhanced micro-computed tomography (EPIC-μCT) was used to confirm that mild OA specimens had significantly higher GAGs content compared to severe OA specimens. In micro-scale, the semi-equilibrium modulus of mild OA specimens significantly dropped after immersion in a hypertonic solution and at nano-scale, the histograms of the measured elastic modulus revealed three to four components. Comparing the peaks with those observed for healthy cartilage in a previous study indicated that the first and third peaks represent the mechanical properties of GAGs and the collagen network. The third peak shows considerably stiffer elastic modulus for mild OA samples as compared to the severe OA samples in isotonic conditions. Furthermore, this peak clearly dropped when the tonicity increased, indicating the loss of collagen (pre-) stress in the shrunk specimen. Our observations support the association of the third peak with the collagen network. However, our results did not provide any direct evidence to support the association of the first peak with GAGs. For severe OA specimens, the peak associated with the collagen network did not drop when the tonicity increased, indicating a change in the response of OA cartilage to hypertonicity, likely collagen damage, as the disease progresses to its latest stages.
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Affiliation(s)
- P R Moshtagh
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Department of Orthopaedics, University Medical Center Utrecht, Q.03.2.103-1, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
| | - B Pouran
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Department of Orthopaedics, University Medical Center Utrecht, Q.03.2.103-1, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
| | - J van Tiel
- Department of Orthopaedics and Radiology, Erasmus Medical Centre, Rotterdam, The Netherlands.
| | - J Rauker
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
| | - M R Zuiddam
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands.
| | - V Arbabi
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
| | - N M Korthagen
- Department of Orthopaedics, University Medical Center Utrecht, Q.03.2.103-1, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands; Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
| | - H Weinans
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Department of Orthopaedics, University Medical Center Utrecht, Q.03.2.103-1, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands; Department of Rheumatology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - A A Zadpoor
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
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Arbabi V, Pouran B, Weinans H, Zadpoor AA. Transport of Neutral Solute Across Articular Cartilage: The Role of Zonal Diffusivities. J Biomech Eng 2015; 137:2210662. [DOI: 10.1115/1.4030070] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Indexed: 02/02/2023]
Abstract
Transport of solutes through diffusion is an important metabolic mechanism for the avascular cartilage tissue. Three types of interconnected physical phenomena, namely mechanical, electrical, and chemical, are all involved in the physics of transport in cartilage. In this study, we use a carefully designed experimental-computational setup to separate the effects of mechanical and chemical factors from those of electrical charges. Axial diffusion of a neutral solute (Iodixanol) into cartilage was monitored using calibrated microcomputed tomography (micro-CT) images for up to 48 hr. A biphasic-solute computational model was fitted to the experimental data to determine the diffusion coefficients of cartilage. Cartilage was modeled either using one single diffusion coefficient (single-zone model) or using three diffusion coefficients corresponding to superficial, middle, and deep cartilage zones (multizone model). It was observed that the single-zone model cannot capture the entire concentration-time curve and under-predicts the near-equilibrium concentration values, whereas the multizone model could very well match the experimental data. The diffusion coefficient of the superficial zone was found to be at least one order of magnitude larger than that of the middle zone. Since neutral solutes were used, glycosaminoglycan (GAG) content cannot be the primary reason behind such large differences between the diffusion coefficients of the different cartilage zones. It is therefore concluded that other features of the different cartilage zones such as water content and the organization (orientation) of collagen fibers may be enough to cause large differences in diffusion coefficients through the cartilage thickness.
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Affiliation(s)
- V. Arbabi
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628CD, The Netherlands e-mail:
| | - B. Pouran
- Department of Orthopedics, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628CD, The Netherlands
| | - H. Weinans
- Department of Orthopedics and Department of Rheumatology, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628CD, Delft, The Netherlands
| | - A. A. Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628CD, The Netherlands
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Amin Yavari S, Ahmadi S, Wauthle R, Pouran B, Schrooten J, Weinans H, Zadpoor A. Relationship between unit cell type and porosity and the fatigue behavior of selective laser melted meta-biomaterials. J Mech Behav Biomed Mater 2015; 43:91-100. [DOI: 10.1016/j.jmbbm.2014.12.015] [Citation(s) in RCA: 248] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/09/2014] [Accepted: 12/11/2014] [Indexed: 01/02/2023]
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