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Lee SK, Han CM, Park W, Kim IH, Joung YK, Han DK. Synergistically enhanced osteoconductivity and anti-inflammation of PLGA/β-TCP/Mg(OH) 2 composite for orthopedic applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 94:65-75. [PMID: 30423751 DOI: 10.1016/j.msec.2018.09.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 08/01/2018] [Accepted: 09/05/2018] [Indexed: 01/20/2023]
Abstract
Synthetic biodegradable polymers including poly(lactide-co-glycolide) (PLGA) have been widely used as alternatives to metallic implantable materials in the orthopedic field due to their superior biocompatibility and biodegradability. However, weak mechanical properties of the biodegradable polymers and inflammatory reaction caused by the acidic degradation products have limited their biomedical applications. In this study, we have developed a PLGA composite containing beta-tricalcium phosphate (β-TCP) and magnesium hydroxide (Mg(OH)2) as additives to improve mechanical, osteoconductivity, and anti-inflammation property of the biopolymer composite simultaneously. The β-TCP has an osteoconductive effect and the Mg(OH)2 has a pH neutralizing effect. The PLGA/inorganic composites were uniformly blended via a twin extrusion process. The mechanical property of the PLGA/β-TCP/Mg(OH)2 composite was improved compared to the pure PLGA. In particular, the addition of Mg(OH)2 suppressed the inflammatory reaction of normal human osteoblast (NHOst) cells and also inhibited the differentiation of pre-osteoclastic cells into osteoclasts. Moreover, synergistically upregulated late osteogenic differentiation of NHOst cells was observed on the PLGA/β-TCP/Mg(OH)2 composite. Taken all together, we believe that the use of β-TCP and Mg(OH)2 as additives with synthetic biodegradable polymers has great potential by the synergistic effect in orthopedic applications.
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Affiliation(s)
- Seul Ki Lee
- Department of Biomedical Science, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi 13488, Republic of Korea; Department of Biological Science, Korea University, Seoul 02841, Republic of Korea
| | - Cheol-Min Han
- Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Wooram Park
- Department of Biomedical Science, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi 13488, Republic of Korea
| | - Ik Hwan Kim
- Department of Biological Science, Korea University, Seoul 02841, Republic of Korea
| | - Yoon Ki Joung
- Center for Biomaterials, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biomedical Engineering, Korea University of Science and Technology, Daejeon 34113, Republic of Korea.
| | - Dong Keun Han
- Department of Biomedical Science, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi 13488, Republic of Korea.
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52
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da Silva D, Kaduri M, Poley M, Adir O, Krinsky N, Shainsky-Roitman J, Schroeder A. Biocompatibility, biodegradation and excretion of polylactic acid (PLA) in medical implants and theranostic systems. CHEMICAL ENGINEERING JOURNAL (LAUSANNE, SWITZERLAND : 1996) 2018; 340:9-14. [PMID: 31384170 PMCID: PMC6682490 DOI: 10.1016/j.cej.2018.01.010] [Citation(s) in RCA: 316] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Polylactic acid (PLA) is the most commonly used biodegradable polymer in clinical applications today. Examples range from drug delivery systems, tissue engineering, temporary and long-term implantable devices; constantly expanding to new fields. This is owed greatly to the polymer's favorable biocompatibility and to its safe degradation products. Once coming in contact with biological media, the polymer begins breaking down, usually by hydrolysis, into lactic acid (LA) or to carbon dioxide and water. These products are metabolized intracellularly or excreted in the urine and breath. Bacterial infection and foreign-body inflammation enhance the breakdown of PLA, through the secretion of enzymes that degrade the polymeric matrix. The biodegradation occurs both on the surface of the polymeric device and inside the polymer body, by diffusion of water between the polymer chains. The median half-life of the polymer is 30 weeks; however, this can be lengthened or shortened to address the clinical needs. Degradation kinetics can be tuned by determining the molecular composition and the physical architecture of the device. Using L- or D- chirality of the LA will greatly slow or lengthen the degradation rates, respectively. Despite the fact that this polymer is more than 150 years old, PLA remains a fertile platform for biomedical innovation and fundamental understanding of how artificial polymers can safely coexist with biological systems.
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Affiliation(s)
- Dana da Silva
- Laboratory for Targeted Drug Delivery and Personalized Medicine Technologies, Department of Chemical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Maya Kaduri
- Laboratory for Targeted Drug Delivery and Personalized Medicine Technologies, Department of Chemical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Maria Poley
- Laboratory for Targeted Drug Delivery and Personalized Medicine Technologies, Department of Chemical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Omer Adir
- Laboratory for Targeted Drug Delivery and Personalized Medicine Technologies, Department of Chemical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
- The Norman Seiden Multidisciplinary Program for Nanoscience and Nanotechnology, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Nitzan Krinsky
- Laboratory for Targeted Drug Delivery and Personalized Medicine Technologies, Department of Chemical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
- The Interdisciplinary Program for Biotechnology, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Janna Shainsky-Roitman
- Laboratory for Targeted Drug Delivery and Personalized Medicine Technologies, Department of Chemical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
| | - Avi Schroeder
- Laboratory for Targeted Drug Delivery and Personalized Medicine Technologies, Department of Chemical Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
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53
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Urbanek O, Kołbuk D, Wróbel M. Articular cartilage: New directions and barriers of scaffolds development – review. INT J POLYM MATER PO 2018. [DOI: 10.1080/00914037.2018.1452224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Olga Urbanek
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Kołbuk
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Mikołaj Wróbel
- Ortopedika – Centre for Specialized Surgery, Warsaw, Poland
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Schaller B, Matthias Burkhard JP, Chagnon M, Beck S, Imwinkelried T, Assad M. Fracture Healing and Bone Remodeling With Human Standard-Sized Magnesium Versus Polylactide-Co-Glycolide Plate and Screw Systems Using a Mini-Swine Craniomaxillofacial Osteotomy Fixation Model. J Oral Maxillofac Surg 2018; 76:2138-2150. [PMID: 29684308 DOI: 10.1016/j.joms.2018.03.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/27/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
Abstract
PURPOSE This study compared the degradation profile, safety, and efficacy of bioresorbable magnesium alloy and polylactide-co-glycolide (PLGA) polymer osteosynthesis systems for the treatment of fractures in a load-sharing maxillofacial environment using a new mini-swine fracture fixation model. MATERIALS AND METHODS Two types of clinically relevant situations were evaluated in 5 Yucatan miniature pigs. Defined porcine midface osteotomies of the supraorbital rim and zygoma were created and fixed with either a coated magnesium (test animals) or PLGA plate and screw osteosynthesis system (control animals). After surgery, the mini-pigs were able to recover for either 1 or 9 months with continuous in vivo post-implantation monitoring. Standardized computed tomography (CT) imaging was taken immediately postoperatively and at termination for all animals. The 9-month cohort also underwent CT at 2, 4, and 6 months after surgery. At necropsy, osteotomy sites and bone-implant units were harvested, and healing was evaluated by micro-CT, histopathology, and histomorphometry. RESULTS After clinical and radiologic follow-up examination, all fracture sites healed well for both the magnesium and polymer groups regardless of time point. Complete bone union and gradually disappearing osteotomy lines were observed across all implantation sites, with no major consistency change in periprosthetic soft tissue or in soft tissue calcification. Macroscopic and microscopic examination showed no negative influence of gas formation observed with magnesium during the healing process. Histopathologic analysis showed similar fracture healing outcomes for both plating systems with good biocompatibility as evidenced by a minimal or mild tissue reaction. CONCLUSIONS This study confirms that WE43 magnesium alloy exhibited excellent fracture healing properties before its full degradation without causing any substantial inflammatory reactions in a long-term porcine model. Compared with PLGA implants, magnesium represents a promising new biomaterial with reduced implant sizes and improved mechanical properties to support fracture healing in a load-sharing environment.
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Affiliation(s)
- Benoît Schaller
- Senior Physician, Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital, Bern, Switzerland.
| | | | | | - Stefan Beck
- Senior Scientist, Materials Group, Synthes Biomaterials, Oberdorf, Switzerland
| | | | - Michel Assad
- Director, Orthopedics and Biomaterials, AccelLAB, Boisbriand, Quebec, Canada
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Xu TO, Kim HS, Stahl T, Nukavarapu SP. Self-neutralizing PLGA/magnesium composites as novel biomaterials for tissue engineering. Biomed Mater 2018; 13:035013. [PMID: 29362293 PMCID: PMC5884090 DOI: 10.1088/1748-605x/aaaa29] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Controlling acidic degradation of biodegradable polyesters remains a major clinical challenge. This work presents a simple and effective strategy of developing polyester composites with biodegradable magnesium metal or alloys. PLGA samples with compositions of 1, 3, 5, and 10 wt% magnesium were produced using a simple solvent-casting method, which resulted in composite films with near uniform Mg metal/alloy particle dispersion. Degradation study of the composite films showed that all compositions higher than 1 wt% magnesium were able to extend the duration of degradation, and buffer acidic pH resulting from PLGA degradation. PLGA composite with 5 wt% of magnesium showed near-neutral degradation pattern under sink conditions. Magnesium addition also showed improved mechanical characteristics in terms of the tensile modulus. In vitro experiments conducted by seeding PLGA composites with MC3T3-E1 pre-osteoblasts demonstrated increased ALP expression and cellular mineralization. The established new biodegradable polymer-metal system provides a useful biomaterial platform with a wide range of applications in biomedical device development and scaffold-based tissue engineering.
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Affiliation(s)
- Thomas O Xu
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington CT, United States of America. These authors contributed equally
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56
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Gritsch L, Lovell C, Goldmann WH, Boccaccini AR. Do bioresorbable polyesters have antimicrobial properties? JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2018; 29:18. [PMID: 29340853 PMCID: PMC5770478 DOI: 10.1007/s10856-017-6021-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/06/2017] [Indexed: 06/07/2023]
Abstract
Biodegradable and bioresorbable polyesters (BBPEs) are a widespread class of aliphatic polymers with a plethora of applications in the medical field. Some reports speculate that these polymers have intrinsic antibacterial activity as a consequence of their acidic degradation by-products. The release of organic acids as a result of the hydrolytic degradation of BBPEs in vivo and the resulting pH drop could be an effective inhibitor of the growth of pathogens in the local environment adjacent to BBPE-based devices. However, there is no clear and conclusive evidence in the literature concerning the antibacterial activity of BBPE to support or refute this hypothesis. In this communication we address this point through an assessment of the antibacterial properties of six well-established commercially available BBPEs. Agar diffusion assays and optical density measurements at 600 nm were performed on all the polymer samples to characterize the growth of bacteria and any potential inhibition over an incubation period of 24 h. The results indicated that BBPEs do not possess an intrinsic and immediate antibacterial activity, which is consistent with the clear mismatch between the time-scales for bacterial growth and the rate of degradation of the polyesters.
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Affiliation(s)
- Lukas Gritsch
- Institute of Biomaterials, University of Erlangen-Nuremberg, Cauerstraße 6, 91058, Erlangen, Germany
- Lucideon Ltd., Queens Road, Penkhull, Stoke-on-Trent, Staffordshire, ST4 7LQ, UK
| | - Christopher Lovell
- Lucideon Ltd., Queens Road, Penkhull, Stoke-on-Trent, Staffordshire, ST4 7LQ, UK
| | - Wolfgang H Goldmann
- Department of Biophysics, University of Erlangen-Nuremberg, Henkestrasse 91, 91052, Erlangen, Germany
| | - Aldo R Boccaccini
- Institute of Biomaterials, University of Erlangen-Nuremberg, Cauerstraße 6, 91058, Erlangen, Germany.
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57
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Cipriano AF, Lin J, Lin A, Sallee A, Le B, Alcaraz MCC, Guan RG, Botimer G, Inceođlu S, Liu H. Degradation of Bioresorbable Mg-4Zn-1Sr Intramedullary Pins and Associated Biological Responses in Vitro and in Vivo. ACS APPLIED MATERIALS & INTERFACES 2017; 9:44332-44355. [PMID: 29239597 PMCID: PMC5772744 DOI: 10.1021/acsami.7b15975] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
This article reports the degradation and biological properties of as-drawn Mg-4Zn-1Sr (designated as ZSr41) and pure Mg (P-Mg) wires as bioresorbable intramedullary pins for bone repair. Specifically, their cytocompatibility with bone marrow derived mesenchymal stem cells (BMSCs) and degradation in vitro, and their biological effects on peri-implant tissues and in vivo degradation in rat tibiae were studied. The as-drawn ZSr41 pins showed a significantly faster degradation than P-Mg in vitro and in vivo. The in vivo average daily degradation rates of both ZSr41 and P-Mg intramedullary pins were significantly greater than their respective in vitro degradation rates, likely because the intramedullary site of implantation is highly vascularized for removal of degradation products. Importantly, the concentrations of Mg2+, Zn2+, and Sr2+ ions in the BMSC culture in vitro and their concentrations in rat blood in vivo were all lower than their respective therapeutic dosages, i.e., in a safe range. Despite of rapid degradation with a complete resorption time of 8 weeks in vivo, the ZSr41 intramedullary pins showed a significant net bone growth because of stimulatory effects of the metallic ions released. However, proportionally released OH- ions and hydrogen gas caused adverse effects on bone marrow cells and resulted in cavities in surrounding bone. Thus, properly engineering the degradation properties of Mg-based implants is critical for harvesting the bioactivities of beneficial metallic ions, while controlling adverse reactions associated with the release of OH- ions and hydrogen gas. It is necessary to further optimize the alloy processing conditions and/or modify the surfaces, for example, applying coatings onto the surface, to reduce the degradation rate of ZSr41 wires for skeletal implant applications.
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Affiliation(s)
- Aaron F. Cipriano
- Department of Bioengineering, University of California, Riverside California 92521. United States
- Materials Science & Engineering, University of California, Riverside California 92521. United States
| | - Jiajia Lin
- Materials Science & Engineering, University of California, Riverside California 92521. United States
| | - Alan Lin
- Department of Bioengineering, University of California, Riverside California 92521. United States
| | - Amy Sallee
- Department of Bioengineering, University of California, Riverside California 92521. United States
| | - Belinda Le
- Department of Bioengineering, University of California, Riverside California 92521. United States
| | | | - Ren-Guo Guan
- School of Materials Science and Engineering, Northeastern University, Shenyang 110819. China
| | - Gary Botimer
- Department of Orthopedic Surgery, Loma Linda University, Loma Linda, California 92354. United States
| | - Serkan Inceođlu
- Department of Orthopedic Surgery, Loma Linda University, Loma Linda, California 92354. United States
| | - Huinan Liu
- Department of Bioengineering, University of California, Riverside California 92521. United States
- Materials Science & Engineering, University of California, Riverside California 92521. United States
- Stem Cell Center, University of California, Riverside California 92521. United States
- Cell, Molecular and Developmental Biology Program, University of California, Riverside California 92521. United States
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58
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Cipriano AF, Lin J, Miller C, Lin A, Cortez Alcaraz MC, Soria P, Liu H. Anodization of magnesium for biomedical applications - Processing, characterization, degradation and cytocompatibility. Acta Biomater 2017; 62:397-417. [PMID: 28818688 DOI: 10.1016/j.actbio.2017.08.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/17/2017] [Accepted: 08/12/2017] [Indexed: 01/05/2023]
Abstract
This article reports anodization of Mg in KOH electrolyte and the associated surface, degradation, and biological properties for bioresorbable implant applications. The preparation procedures for electrodes and anodization setup significantly enhanced reproducibility of samples. The results of anodization performed at the applied potentials of 1.8, 1.9, or 2.0V showed that the sample anodized at 1.9V and annealed, referred to as the 1.9 AA sample, had homogenous surface microstructure and elemental composition, and a reduction in corrosion current density in the electrochemical testing. In comparison with Mg control, the 1.9 AA sample showed a distinct mode of degradation, e.g., continuous growth of a passivation layer enriched with Ca and P instead of typical localized pitting and undermining, and a greater release rate of Mg2+ ions when immersed in physiologically relevant media. In the direct culture with bone marrow derived mesenchymal stem cells (BMSCs) in vitro, the 1.9 AA sample did not affect BMSC adhesion and morphology under indirect contact; however, the 1.9 AA sample showed a reduction in cell spreading under direct contact. The change in surface topography/composition at the dynamic interface of the anodized-annealed Mg sample might have contributed to the change in BMSC morphology. In summary, this study demonstrated the potential of anodic oxidation to modulate the degradation behaviors of Mg-based biomaterials and BMSC responses in vitro, and confirmed the value of direct culture method for studying cytocompatibility of Mg-based biomaterials for medical implant applications. STATEMENT OF SIGNIFICANCE Magnesium (Mg)-based biomaterials have been specifically designed and actively explored for biodegradable implant applications since the early 2000s. To realize the benefits of Mg-based materials for medical implant applications, it is critical to control the rate of Mg degradation (i.e. corrosion) in the body. We investigated an environmentally friendly anodization process using KOH electrolyte for modifying the surface of Mg-based materials, and the resulted surface, degradation, and biological properties for biomedical applications. This study reported critical considerations that are important for repeatability of anodization process, homogeneity of surface microstructure and composition, and in vitro evaluations of the degradation and biological properties of surface treated Mg samples. The details in preparation of electrodes, anodization setup, annealing, and sample handling before and after surface treatment (e.g. re-embedding) reported in this article are valuable for studying a variety of electrochemical processes for surface treatment of Mg-based metals, because of enhanced reproducibility.
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Affiliation(s)
- Aaron F Cipriano
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; Materials Science & Engineering, University of California, Riverside, CA 92521, USA
| | - Jiajia Lin
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; Materials Science & Engineering, University of California, Riverside, CA 92521, USA
| | - Christopher Miller
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Alan Lin
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | | | - Pedro Soria
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; Department of Biology, California State University, San Bernardino, CA 92407, USA; Stem Cell Center, University of California, Riverside, CA 92521, USA
| | - Huinan Liu
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; Materials Science & Engineering, University of California, Riverside, CA 92521, USA; Stem Cell Center, University of California, Riverside, CA 92521, USA; Cell, Molecular and Developmental Biology Program, University of California, Riverside, CA 92521, USA.
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Narayanan G, Bhattacharjee M, Nair LS, Laurencin CT. Musculoskeletal Tissue Regeneration: the Role of the Stem Cells. REGENERATIVE ENGINEERING AND TRANSLATIONAL MEDICINE 2017. [DOI: 10.1007/s40883-017-0036-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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60
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Swain SK, Gotman I, Unger R, Gutmanas EY. Bioresorbable β-TCP-FeAg nanocomposites for load bearing bone implants: High pressure processing, properties and cell compatibility. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 78:88-95. [PMID: 28576063 DOI: 10.1016/j.msec.2017.04.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/01/2017] [Accepted: 04/03/2017] [Indexed: 01/28/2023]
Abstract
In this paper, the processing and properties of iron-toughened bioresorbable β-tricalcium phosphate (β-TCP) nanocomposites are reported. β-TCP is chemically similar to bone mineral and thus a good candidate material for bioresorbable bone healing devices; however intrinsic brittleness and low bending strength make it unsuitable for use in load-bearing sites. Near fully dense β-TCP-matrix nanocomposites containing 30vol% Fe, with and without addition of silver, were produced employing high energy attrition milling of powders followed by high pressure consolidation/cold sintering at 2.5GPa. In order to increase pure iron's corrosion rate, 10 to 30vol% silver were added to the metal phase. The degradation behavior of the developed composite materials was studied by immersion in Ringer's and saline solutions for up to 1month. The mechanical properties, before and after immersion, were tested in compression and bending. All the compositions exhibited high mechanical strength, the strength in bending being several fold higher than that of polymer toughened β-TCP-30PLA nanocomposites prepared by the similar procedure of attrition milling and cold sintering, and of pure high-temperature sintered β-TCP. Partial substitution of iron with silver led to an increase in both strength and ductility. Furthermore, the galvanic action of silver particles dispersed in the iron phase significantly accelerated in vitro degradation of β-TCP-30(Fe-Ag) nanocomposites. After 1month immersion, the composites retained about 50% of their initial bending strength. In cell culture experiments, β-TCP-27Fe3Ag nanocomposites exhibited no signs of cytotoxicity towards human osteoblasts suggesting that they can be used as an implant material.
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Affiliation(s)
- S K Swain
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - I Gotman
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel; National Research Tomsk Polytechnic University, Tomsk 634050, Russian Federation
| | - R Unger
- Institute of Pathology, University Medical Center of the Johannes Gutenberg University, 55101 Mainz, Germany
| | - E Y Gutmanas
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel; National Research Tomsk Polytechnic University, Tomsk 634050, Russian Federation.
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61
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Cipriano AF, Sallee A, Guan RG, Lin A, Liu H. A Comparison Study on the Degradation and Cytocompatibility of Mg-4Zn- xSr Alloys in Direct Culture. ACS Biomater Sci Eng 2017; 3:540-550. [PMID: 33429621 DOI: 10.1021/acsbiomaterials.6b00684] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This article reports the behaviors of bone-marrow-derived mesenchymal stem cells (BMSCs) in the direct culture with four Mg-4Zn-xSr alloys (x = 0.15, 0.5, 1.0, 1.5 wt %), designated as ZSr41A, B, C, and D, respectively; and a systematic comparison on the degradation of the ZSr41 alloys and their biological impact in the direct culture with different cell types in their respective media. The direct culture method, in which cells are seeded directly onto the surface of the sample, was used to investigate cellular responses at the cell-biomaterial interface in vitro. The results showed that BMSCs adhered and remained viable on the surfaces of all ZSr41 alloys, but the faster degrading ZSr41A and ZSr41B alloys showed a significantly lower amount of viable BMSCs adhered to their surfaces. Moreover, BMSCs adhered to the culture plate surrounding the samples were unaffected by the solubilized degradation products from the ZSr41 alloys. The results from the comparison study showed that the in vitro degradation rates of Mg-based biomaterials in different culture systems might be mostly affected by media buffer capacity (i.e., HCO3- concentration), and to a lesser extent, d-glucose concentration. The comparison study also indicated that BMSCs were more robust than H9 human embryonic stem cells and human umbilical vein endothelial cells for screening the cytocompatibility of Mg-based biomaterials. In general, the adhesion and viability of BMSCs at the cell-material interface were inversely proportional to the alloy degradation rates. This study presented a clinically relevant in vitro culture system for screening bioresorbable alloys in direct culture, and provided valuable guidelines for determining the degradation rates of Mg-based biomaterials.
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Affiliation(s)
| | | | - Ren-Guo Guan
- School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
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Antibacterial ability and angiogenic activity of Cu-Ti-O nanotube arrays. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 71:93-99. [DOI: 10.1016/j.msec.2016.09.077] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/09/2016] [Accepted: 09/29/2016] [Indexed: 02/02/2023]
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63
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Cipriano AF, Sallee A, Tayoba M, Cortez Alcaraz MC, Lin A, Guan RG, Zhao ZY, Liu H. Cytocompatibility and early inflammatory response of human endothelial cells in direct culture with Mg-Zn-Sr alloys. Acta Biomater 2017; 48:499-520. [PMID: 27746360 PMCID: PMC5873597 DOI: 10.1016/j.actbio.2016.10.020] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 10/04/2016] [Accepted: 10/12/2016] [Indexed: 12/18/2022]
Abstract
Crystalline Mg-Zinc (Zn)-Strontium (Sr) ternary alloys consist of elements naturally present in the human body and provide attractive mechanical and biodegradable properties for a variety of biomedical applications. The first objective of this study was to investigate the degradation and cytocompatibility of four Mg-4Zn-xSr alloys (x=0.15, 0.5, 1.0, 1.5wt%; designated as ZSr41A, B, C, and D respectively) in the direct culture with human umbilical vein endothelial cells (HUVEC) in vitro. The second objective was to investigate, for the first time, the early-stage inflammatory response in cultured HUVECs as indicated by the induction of vascular cellular adhesion molecule-1 (VCAM-1). The results showed that the 24-h in vitro degradation of the ZSr41 alloys containing a β-phase with a Zn/Sr at% ratio ∼1.5 was significantly faster than the ZSr41 alloys with Zn/Sr at% ∼1. Additionally, the adhesion density of HUVECs in the direct culture but not in direct contact with the ZSr41 alloys for up to 24h was not adversely affected by the degradation of the alloys. Importantly, neither culture media supplemented with up to 27.6mM Mg2+ ions nor media intentionally adjusted up to alkaline pH 9 induced any detectable adverse effects on HUVEC responses. In contrast, the significantly higher, yet non-cytotoxic, Zn2+ ion concentration from the degradation of ZSr41D alloy was likely the cause for the initially higher VCAM-1 expression on cultured HUVECs. Lastly, analysis of the HUVEC-ZSr41 interface showed near-complete absence of cell adhesion directly on the sample surface, most likely caused by either a high local alkalinity, change in surface topography, and/or surface composition. The direct culture method used in this study was proposed as a valuable tool for studying the design aspects of Zn-containing Mg-based biomaterials in vitro, in order to engineer solutions to address current shortcomings of Mg alloys for vascular device applications. STATEMENT OF SIGNIFICANCE Magnesium (Mg) alloys specifically designed for biodegradable implant applications have been the focus of biomedical research since the early 2000s. Physicochemical properties of Mg alloys make these metallic biomaterials excellent candidates for temporary biodegradable implants in orthopedic and cardiovascular applications. As Mg alloys continue to be investigated for biomedical applications, it is necessary to understand whether Mg-based materials or the alloying elements have the intrinsic ability to direct an immune response to improve implant integration while avoiding cell-biomaterial interactions leading to chronic inflammation and/or foreign body reactions. The present study utilized the direct culture method to investigate for the first time the in vitro transient inflammatory activation of endothelial cells induced by the degradation products of Zn-containing Mg alloys.
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Affiliation(s)
- Aaron F Cipriano
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; Materials Science & Engineering Program, University of California, Riverside, CA 92521, USA
| | - Amy Sallee
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Myla Tayoba
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | | | - Alan Lin
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Ren-Guo Guan
- School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China
| | - Zhan-Yong Zhao
- School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China
| | - Huinan Liu
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; Materials Science & Engineering Program, University of California, Riverside, CA 92521, USA; Stem Cell Center, University of California, Riverside, CA 92521, USA; Cell, Molecular and Developmental Biology Program, University of California, Riverside, CA 92521, USA.
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64
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Ramot Y, Haim-Zada M, Domb AJ, Nyska A. Biocompatibility and safety of PLA and its copolymers. Adv Drug Deliv Rev 2016; 107:153-162. [PMID: 27058154 DOI: 10.1016/j.addr.2016.03.012] [Citation(s) in RCA: 285] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 03/24/2016] [Accepted: 03/26/2016] [Indexed: 12/20/2022]
Abstract
PLA and its copolymers are commonly used for a wide variety of applications. While they are considered to be biocompatible, side effects resulting from their implantation have been reported. The implantation of biomaterials always results in a foreign body reaction. Such a reaction has also been reported following PLA and its copolymers. This article reviews the process of inflammatory reaction that is to be expected following implantation of PLA, and it highlights specific cases in which the inflammatory reaction can result in safety concerns. The authors also review selected cases from different medical fields to demonstrate possible clinical side effects resulting from its use.
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Mouthuy PA, Snelling SJ, Dakin SG, Milković L, Gašparović AČ, Carr AJ, Žarković N. Biocompatibility of implantable materials: An oxidative stress viewpoint. Biomaterials 2016; 109:55-68. [DOI: 10.1016/j.biomaterials.2016.09.010] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/06/2016] [Accepted: 09/13/2016] [Indexed: 12/13/2022]
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Current status on clinical applications of magnesium-based orthopaedic implants: A review from clinical translational perspective. Biomaterials 2016; 112:287-302. [PMID: 27770632 DOI: 10.1016/j.biomaterials.2016.10.017] [Citation(s) in RCA: 353] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 10/10/2016] [Accepted: 10/11/2016] [Indexed: 12/30/2022]
Abstract
As a new generation of medical metallic material, magnesium (Mg) and its alloys with or without surface coating have attracted a great deal of attention due to its biodegradability and potential for avoiding a removal operation after the implant has fulfilled its function for surgical fixation of injured musculoskeletal tissues. Although a few clinical cases on Mg-based orthopaedic implants were reported more than a century ago, it was not until recently that clinical trials using these implants with improved physicochemical properties were carried out in Germany, China and Korea for bone fracture fixation. The promising results so far suggest a bright future for biodegradable Mg-based orthopaedic implants and would warrant large scale phase II/III studies. Given the increasing interest on this emerging biomaterials and intense effort to improve its properties for various clinical applications, this review covers the evolution, current strategies, and future perspectives in the development of Mg-based orthopaedic implants. We also highlight a few clinical cases performed in China that may be unfamiliar to the general orthopaedic community.
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67
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A novel open-porous magnesium scaffold with controllable microstructures and properties for bone regeneration. Sci Rep 2016; 6:24134. [PMID: 27071777 PMCID: PMC4829853 DOI: 10.1038/srep24134] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/21/2016] [Indexed: 12/05/2022] Open
Abstract
The traditional production methods of porous magnesium scaffolds are difficult to accurately control the pore morphologies and simultaneously obtain appropriate mechanical properties. In this work, two open-porous magnesium scaffolds with different pore size but in the nearly same porosity are successfully fabricated with high-purity Mg ingots through the titanium wire space holder (TWSH) method. The porosity and pore size can be easily, precisely and individually controlled, as well as the mechanical properties also can be regulated to be within the range of human cancellous bone by changing the orientation of pores without sacrifice the requisite porous structures. In vitro cell tests indicate that the scaffolds have good cytocompatibility and osteoblastic differentiation properties. In vivo findings demonstrate that both scaffolds exhibit acceptable inflammatory responses and can be almost fully degraded and replaced by newly formed bone. More importantly, under the same porosity, the scaffolds with larger pore size can promote early vascularization and up-regulate collagen type 1 and OPN expression, leading to higher bone mass and more mature bone formation. In conclusion, a new method is introduced to develop an open-porous magnesium scaffold with controllable microstructures and mechanical properties, which has great potential clinical application for bone reconstruction in the future.
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68
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Amini AR, Xu TO, Chidambaram RM, Nukavarapu SP. Oxygen Tension-Controlled Matrices with Osteogenic and Vasculogenic Cells for Vascularized Bone Regeneration In Vivo. Tissue Eng Part A 2016; 22:610-20. [PMID: 26914219 PMCID: PMC4841084 DOI: 10.1089/ten.tea.2015.0310] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 02/23/2016] [Indexed: 12/23/2022] Open
Abstract
Despite recent progress, segmental bone defect repair is still a significant challenge in orthopedic surgery. While bone tissue engineering approaches using biodegradable matrices along with bone/blood vessel forming cells offered improved possibilities, current regenerative strategies lack the ability to achieve vascularized bone regeneration in critical-sized/segmental bone defects. In this study, we introduced and evaluated a two-pronged approach for vascularized bone regeneration in vivo. The goal was to demonstrate vascularized bone formation using oxygen tension-controlled (OTC) matrices seeded with bone and blood vessel forming cells. OTC matrices were coimplanted with rabbit mesenchymal stem cells (MSCs) and peripheral blood-derived endothelial progenitor cells (PB-EPCs) to demonstrate the osteogenic and vasculogenic differentiation of these cells, postseeding on a matrix, especially deep inside the matrix pore structure. Matrices coimplanted with varied rabbit MSC and PB-EPC ratios (1:4, 1:1, and 4:1) were assessed in a nude mouse subcutaneous implantation model to determine a coimplantation ratio with superior osteogenic as well as vasculogenic properties. The implants were analyzed, at week 8, for endothelial (CD31 and Von Willebrand factor [vWF]) and osteogenic marker (RunX2 and Col I) staining qualitatively and collagen deposition and number of vessel formation quantitatively. Results from these experiments established MSC-to-PB-EPC ratio 1:1 as the best coimplantation ratio. OTC matrix with 1:1 coimplantation ratio was assessed for segmental bone defect repair in a rabbit critical-sized bone defect model. The group under investigation was OTC matrix, and the matrix was seeded with MSCs, EPCs, or MSCs:EPCs in a 1:1 ratio. Explants at week 12 were evaluated for bone defect repair via micro-CT and histology. Results from rabbit in vivo experiments show enhanced mineralization and vascularization for the 1:1 coimplantation group. Overall, the study establishes a two-pronged approach involving OTC matrix and effective progenitors for large-area and vascularized bone regeneration.
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Affiliation(s)
- Ami R. Amini
- Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, Massachusetts
- Institute for Regenerative Engineering, University of Connecticut Health Center, Farmington, Connecticut
| | - Thomas O. Xu
- Institute for Regenerative Engineering, University of Connecticut Health Center, Farmington, Connecticut
- Department of Orthopedic Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Ramaswamy M. Chidambaram
- Center for Comparative Medicine, University of Connecticut Health Center, Farmington, Connecticut
| | - Syam P. Nukavarapu
- Institute for Regenerative Engineering, University of Connecticut Health Center, Farmington, Connecticut
- Department of Orthopedic Surgery, University of Connecticut Health Center, Farmington, Connecticut
- Department of Materials Science & Engineering, University of Connecticut, Storrs, Connecticut
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut
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69
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Rahim MI, Rohde M, Rais B, Seitz JM, Mueller PP. Susceptibility of metallic magnesium implants to bacterial biofilm infections. J Biomed Mater Res A 2016; 104:1489-99. [DOI: 10.1002/jbm.a.35680] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/29/2016] [Accepted: 02/05/2016] [Indexed: 12/29/2022]
Affiliation(s)
- Muhammad Imran Rahim
- Helmholtz Centre for Infection Research; Inhoffenstrasse 7 Braunschweig 38124 Germany
| | - Manfred Rohde
- Helmholtz Centre for Infection Research; Inhoffenstrasse 7 Braunschweig 38124 Germany
| | - Bushra Rais
- Helmholtz Centre for Infection Research; Inhoffenstrasse 7 Braunschweig 38124 Germany
| | - Jan-Marten Seitz
- Institute of Materials Science, Leibniz University of Hannover; An Der Universität 2 Garbsen 30823 Germany
- Department of Materials Science and Engineering; Michigan Technological University; 1400 Townsend Dr Houghton Michigan 49931
| | - Peter P. Mueller
- Helmholtz Centre for Infection Research; Inhoffenstrasse 7 Braunschweig 38124 Germany
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70
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Yang L, Zhang J, He J, Zhang J, Gan Z. Fabrication, hydrolysis and cell cultivation of microspheres from cellulose-graft-poly(l-lactide) copolymers. RSC Adv 2016. [DOI: 10.1039/c5ra25993b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cellulose-g-PLLA microspheres were fabricated for cell cultivation by a facile solvent evaporation method.
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Affiliation(s)
- Lili Yang
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Engineering Plastics
- Institute of Chemistry
- Chinese Academy of Sciences (CAS)
- Beijing 100190
| | - Jinming Zhang
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Engineering Plastics
- Institute of Chemistry
- Chinese Academy of Sciences (CAS)
- Beijing 100190
| | - Jiasong He
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Engineering Plastics
- Institute of Chemistry
- Chinese Academy of Sciences (CAS)
- Beijing 100190
| | - Jun Zhang
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Engineering Plastics
- Institute of Chemistry
- Chinese Academy of Sciences (CAS)
- Beijing 100190
| | - Zhihua Gan
- State Key Laboratory of Organic–Inorganic Composites
- Beijing Laboratory of Biomaterials
- College of Life Science and Technology
- Beijing University of Chemical Technology
- Beijing 100029
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71
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Bai L, Wu R, Wang Y, Wang X, Zhang X, Huang X, Qin L, Hang R, Zhao L, Tang B. Osteogenic and angiogenic activities of silicon-incorporated TiO2 nanotube arrays. J Mater Chem B 2016; 4:5548-5559. [DOI: 10.1039/c6tb01109h] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Silicon-doped TiO2 nanotube arrays may promote implant osseointegration through upregulating osteoblast and endothelial cell functions.
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Affiliation(s)
- Long Bai
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
| | - Ruifeng Wu
- Department of Orthopedics
- Central Hospital of Tongchuan Mining Bureau
- Tongchuan
- China
| | - Yueyue Wang
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
| | - Xin Wang
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
| | - Xiangyu Zhang
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
| | - Xiaobo Huang
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
| | - Lin Qin
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
| | - Ruiqiang Hang
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
| | - Lingzhou Zhao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases
- Department of Periodontology
- School of Stomatology
- The Fourth Military Medical University
- Xi'an
| | - Bin Tang
- Research Institute of Surface Engineering
- Taiyuan University of Technology
- Taiyuan
- China
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72
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Berglund IS, Jacobs BY, Allen KD, Kim SE, Pozzi A, Allen JB, Manuel MV. Peri-implant tissue response and biodegradation performance of a Mg-1.0Ca-0.5Sr alloy in rat tibia. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 62:79-85. [PMID: 26952400 DOI: 10.1016/j.msec.2015.12.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 11/13/2015] [Accepted: 12/02/2015] [Indexed: 11/18/2022]
Abstract
Biodegradable magnesium (Mg) alloys combine the advantages of traditional metallic implants and biodegradable polymers, having high strength, low density, and a stiffness ideal for bone fracture fixation. A recently developed Mg-Ca-Sr alloy potentially possesses advantageous characteristics over other Mg alloys, such as slower degradation rates and minimal toxicity. In this study, the biocompatibility of this Mg-Ca-Sr alloy was investigated in a rat pin-placement model. Cylindrical pins were inserted in the proximal tibial metaphyses in pre-drilled holes orthogonal to the tibial axis. Implant and bone morphologies were investigated using μCT at 1, 3, and 6 weeks after implant placement. At the same time points, the surrounding tissue was evaluated using H&E, TRAP and Goldner's trichrome staining. Although gas bubbles were observed around the degrading implant at early time points, the bone remained intact with no evidence of microfracture. Principle findings also include new bone formation in the area of the implant, suggesting that the alloy is a promising candidate for biodegradable orthopedic implants.
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Affiliation(s)
- Ida S Berglund
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Brittany Y Jacobs
- Department of Biomedical Engineering, University of Florida, Gainesville, FL 32610, USA
| | - Kyle D Allen
- Department of Biomedical Engineering, University of Florida, Gainesville, FL 32610, USA
| | - Stanley E Kim
- Department of Small Animal Clinical Sciences, Gainesville, FL 32610, USA
| | - Antonio Pozzi
- Department of Small Animal Clinical Sciences, Gainesville, FL 32610, USA; Clinic of Small Animal Surgery, University of Zurich, Switzerland
| | - Josephine B Allen
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Michele V Manuel
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
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73
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Rössig C, Angrisani N, Helmecke P, Besdo S, Seitz JM, Welke B, Fedchenko N, Kock H, Reifenrath J. In vivo evaluation of a magnesium-based degradable intramedullary nailing system in a sheep model. Acta Biomater 2015; 25:369-83. [PMID: 26188326 DOI: 10.1016/j.actbio.2015.07.025] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 07/01/2015] [Accepted: 07/14/2015] [Indexed: 01/10/2023]
Abstract
The biocompatibility and the degradation behavior of the LAE442 magnesium-based intramedullary interlocked nailing system (IM-NS) was assessed in vivo in a comparative study (stainless austenitic steel 1.4441LA) for the first time. IM-NS was implanted into the right tibia (24-week investigation period; nails/screws diameter: 9 mm/3.5 mm, length: 130 mm/15-40 mm) of 10 adult sheep (LAE442, stainless steel, n=5 each group). Clinical and radiographic examinations, in vivo computed tomography (CT), ex vivo micro-computed tomography (μCT), mechanical and histological examinations and element analyses of alloying elements in inner organs were performed. The mechanical examinations (four-point bending) revealed a significant decrease of LAE442 implant stiffness, force at 0.2% offset yield point and maximum force. Periosteal (new bone formation) and endosteal (bone decline) located bone alterations occurred in both groups (LAE442 alloy more pronounced). Moderate gas formation was observed within the LAE442 alloy group. The CT-measured implant volume decreased slightly (not significant). Histologically a predominantly direct bone-to-implant interface existed within the LAE442 alloy group. Formation of a fibrous tissue capsule around the nail occurred in the steel group. Minor inflammatory infiltration was observed in the LAE442 alloy group. Significantly increased quantities of rare earth elements were detected in the LAE442 alloy group. μCT examination showed the beginning of corrosion in dependence of the surrounding tissue. After 24 weeks the local biocompatibility of LAE442 can be considered as suitable for a degradable implant material. STATEMENT OF SIGNIFICANCE An application oriented interlocked intramedullary nailing system in a comparative study (degradable magnesium-based LAE442 alloy vs. steel alloy) was examined in a sheep model for the first time. We focused in particular on the examination of implant degradation by means of (μ-)CT, mechanical properties (four-point bending), clinical compatibility, local bone reactions (X-ray and histology) and possible systemic toxicity (histology and element analyses of inner organs). A significant decrease of magnesium (LAE442 alloy) implant stiffness and maximum force occurred. Moderate not clinically relevant gas accumulation was determined. A predominantly direct bone-to-implant contact existed within the magnesium (LAE442 alloy) group compared to an indirect contact in the steel group. Rare earth element accumulation could be observed in inner organs but H&E staining was inconspicuous.
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74
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Long-term Local and Systemic Safety of Poly(l-lactide-co-epsilon-caprolactone) after Subcutaneous and Intra-articular Implantation in Rats. Toxicol Pathol 2015; 43:1127-40. [DOI: 10.1177/0192623315600275] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The use of biodegradable materials is gaining popularity in medicine, especially in orthopedic applications. However, preclinical evaluation of biodegradable materials can be challenging, since they are located in close contact with host tissues and might be implanted for a long period of time. Evaluation of these compounds requires biodegradability and biocompatibility studies and meticulous pathology examination. We describe 2 preclinical studies performed on Sprague-Dawley rats for 52 weeks, to evaluate clinical pathology, biocompatibility, biodegradability, and systemic toxicity after implantation of 2-layered films or saline-inflated balloon-shaped implants of downsized InSpace™ devices (termed “test device”). The test devices are made from a copolymer of poly-l-lactide-co-∊-caprolactone in a 70:30 ratio, identical to the device used in humans, intended for the treatment of rotator cuff tears. Intra-articular film implantation and subcutaneous implantation of the downsized device showed favorable local and systemic tolerability. Although the implanted materials have no inherent toxic or tumorigenic properties, one animal developed a fibrosarcoma at the implantation site, an event that is associated with a rodent-predilection response where solid materials cause mesenchymal neoplasms. This effect is discussed in the context of biodegradable materials along with a detailed description of expected pathology for biodegradable materials in long-term rodent studies.
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75
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Cytotoxicity Evaluation of Bioresorbable Fixation Screws on Human Gingival Fibroblasts and Mouse Osteoblasts by Real-Time Cell Analysis. J Oral Maxillofac Surg 2015; 73:1562.e1-10. [DOI: 10.1016/j.joms.2015.03.067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 03/18/2015] [Accepted: 03/30/2015] [Indexed: 11/18/2022]
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76
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Olsen TR, Davis LL, Nicolau SE, Duncan CC, Whitehead DC, Van Horn BA, Alexis F. Non-invasive deep tissue imaging of iodine modified poly(caprolactone-co-1-4-oxepan-1,5-dione) using X-ray. Acta Biomater 2015; 20:94-103. [PMID: 25818945 DOI: 10.1016/j.actbio.2015.03.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 03/12/2015] [Accepted: 03/19/2015] [Indexed: 11/29/2022]
Abstract
When biodegradable polyester devices, like sutures and screws, are implanted into the body, it is very challenging to image them in deep tissue, monitor their degradation, and detect defects. We report our recent findings on non-invasive deep tissue imaging of polyester degradation, stability and integrity using an iodinated-polycaprolactone (i-P(CLcoOPD)) X-ray imaging contrast agent. The results of experiments performed with i-P(CLcoOPD) demonstrate the feasibility to quantify in-situ polyester degradation in vitro and in vivo using rats. We also demonstrate that X-ray imaging could be used to identify and quantify physical defects, such as cracks, in polymeric implants using rabbit animal models. This approach enables non-invasive monitoring of polyester materials and is expected to become an important technology for improving the imaging of polymers at clinically relevant depths.
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Affiliation(s)
- Timothy R Olsen
- Department of Bioengineering, Clemson University, Clemson, SC 29634-0905, United States
| | - Lundy L Davis
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29401, United States
| | - Samantha E Nicolau
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29401, United States
| | - Caroline C Duncan
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29401, United States
| | - Daniel C Whitehead
- Department of Chemistry, Clemson University, Clemson, SC 29634-0905, United States.
| | - Brooke A Van Horn
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29401, United States.
| | - Frank Alexis
- Department of Bioengineering, Clemson University, Clemson, SC 29634-0905, United States; Institute of Biological Interfaces of Engineering, Department of Bioengineering, Clemson University, Clemson, SC 29634-0905, United States.
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77
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Weber CM, Eifler R, Seitz JM, Maier HJ, Reifenrath J, Lenarz T, Durisin M. Biocompatibility of MgF2-coated MgNd2 specimens in contact with mucosa of the nasal sinus - a long term study. Acta Biomater 2015; 18:249-61. [PMID: 25769231 DOI: 10.1016/j.actbio.2015.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 01/26/2015] [Accepted: 03/04/2015] [Indexed: 12/28/2022]
Abstract
Up to now, different surgical techniques and stent systems have already been developed and tested for the continuous and adequate ventilation of the frontal sinuses. However, the results achieved still remain poor. Magnesium-based implants have been successfully used in numerous clinical applications. Offering excellent biocompatibility and biodegradability it may be the ideal material for the development of novel implants of the nasal sinus. Here, we present for the first time results on the behaviour of magnesium alloy in a unique environment, i.e. in contact to the nasal mucosa, air and nasal secretion. In a prospective longitudinal study, magnesium fluoride-coated MgNd2 specimens were implanted in the frontal sinuses of 12 minipigs for the investigation of biocompatibility and of the interface between the implant and the mucosa. Endoscopic examinations, histopathological evaluation and EDX measurements were performed regularly up to 180days. Endoscopic evaluation showed focal mucosal reaction, however, without affecting the patency of the sinus. In addition, no signs of bacterial infections were observed. The EDX analyses showed a marginal but steady increase in the Mg concentration in the mucosa over 180days. Histological analysis revealed a locally confined moderate mucosal hyperplasia and unspecific inflammatory reaction. Furthermore, we did not find any osteoinductive effects of the magnesium alloy. The results indicate the excellent biocompatibility of the MgNd2 alloy in contact with nasal mucosa and provide a novel material compound and solid proof-of-principle for the development of magnesium-based nasal stents.
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78
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Stein P, Vitavska O, Kind P, Hoppe W, Wieczorek H, Schürer NY. The biological basis for poly-l-lactic acid-induced augmentation. J Dermatol Sci 2015; 78:26-33. [DOI: 10.1016/j.jdermsci.2015.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/29/2014] [Accepted: 01/20/2015] [Indexed: 12/22/2022]
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79
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Díez-Pascual AM, Díez-Vicente AL. Nano-TiO2 reinforced PEEK/PEI blends as biomaterials for load-bearing implant applications. ACS APPLIED MATERIALS & INTERFACES 2015; 7:5561-5573. [PMID: 25706225 DOI: 10.1021/acsami.5b00210] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Biocompatible ternary nanocomposites based on poly(ether ether ketone) (PEEK)/poly(ether imide) (PEI) blends reinforced with bioactive titanium dioxide (TiO2) nanoparticles were fabricated via ultrasonication followed by melt-blending. The developed biomaterials were characterized using FT-IR, SEM, XRD, DSC, TGA, and DMA. Further, their water-absorption, tensile, tribological, dielectric, and antibacterial properties were evaluated. PEI acts as a coupling agent, since it can interact both with PEEK via π-π stacking and polar interactions as well as with the nanoparticles through hydrogen bonding, as corroborated by the FT-IR spectra, which resulted in a homogeneous titania dispersion within the biopolymer blend without applying any particle surface treatment or polymer functionalization. A change from promotion to retardation in the crystallization rate of the matrix was found with increasing TiO2 concentration, while its crystalline structure remained unaltered. The nanoparticles stiffened, strengthened, and toughened the matrix simultaneously, and the optimal properties were achieved at 4.0 wt % TiO2. More interesting, the tensile properties were retained after steam sterilization in an autoclave or exposure to a simulated body fluid (SBF). The nanocomposites also displayed reduced water absorption though higher thermal stability, storage modulus, glass transition temperature, dielectric constant, and dielectric loss compared to the control blend. Further, remarkable enhancements in the tribological properties under both SBF and dry environments were attained. The nanoparticles conferred antibacterial action versus Gram-positive and Gram-negative bacteria in the presence and the absence of UV light, and the highest inhibition was attained at 4.0 wt % nanoparticle concentration. These nanocomposites are expected to be used in long-term load-bearing implant applications.
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Affiliation(s)
- Ana M Díez-Pascual
- Analytical Chemistry, Physical Chemistry and Chemical Engineering Department, Faculty of Biology, Environmental Sciences and Chemistry, Alcalá University , Alcalá de Henares, Madrid E-28871, Spain
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80
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Ziran NM, Smith WR. The 'Ziran' wrap: reconstruction of critical-sized long bone defects using a fascial autograft and reamer-irrigator-aspirator autograft. Patient Saf Surg 2014; 8:40. [PMID: 25298784 PMCID: PMC4189609 DOI: 10.1186/s13037-014-0040-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 09/10/2014] [Indexed: 11/27/2022] Open
Abstract
Reconstruction of critical-size bony defects remains a challenge to surgeons despite recent technological advances. Current treatments include distraction osteogenesis, cancellous autograft, induced membranes (Masquelet procedure), polymeric membranes, and titanium-mesh cages filled with bone graft. In this article, the authors presents two cases in which critical-sized defects were reconstructed using a meshed fascial autograft encasing reamer-irrigator-aspirator (RIA) autograft and cancellous allograft. This article will discuss the clinical outcomes of the technique, comparison to other current techniques, and technical insight into the potential biological mechanism.
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Affiliation(s)
- Navid M Ziran
- Hip & Pelvis Institute, 2001 Santa Monica Blvd, Suite 760, 90404 Santa Monica, California USA
| | - Wade R Smith
- Mountain Orthopaedic Trauma Surgeons at Swedish, 701 E. Hampden Ave, CO 80113 Englewood, UK
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81
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Cirillo V, Clements BA, Guarino V, Bushman J, Kohn J, Ambrosio L. A comparison of the performance of mono- and bi-component electrospun conduits in a rat sciatic model. Biomaterials 2014; 35:8970-82. [PMID: 25085857 DOI: 10.1016/j.biomaterials.2014.07.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 07/10/2014] [Indexed: 12/16/2022]
Abstract
Synthetic nerve conduits represent a promising strategy to enhance functional recovery in peripheral nerve injury repair. However, the efficiency of synthetic nerve conduits is often compromised by the lack of molecular factors to create an enriched microenvironment for nerve regeneration. Here, we investigate the in vivo response of mono (MC) and bi-component (BC) fibrous conduits obtained by processing via electrospinning poly(ε-caprolactone) (PCL) and gelatin solutions. In vitro studies demonstrate that the inclusion of gelatin leads to uniform electrospun fiber size and positively influences the response of Dorsal Root Ganglia (DRGs) neurons as confirmed by the preferential extensions of neurites from DRG bodies. This behavior can be attributed to gelatin as a bioactive cue for the cultured DRG and to the reduced fibers size. However, in vivo studies in rat sciatic nerve defect model show an opposite response: MC conduits stimulate superior nerve regeneration than gelatin containing PCL conduits as confirmed by electrophysiology, muscle weight and histology. The G-ratio, 0.71 ± 0.07 for MC and 0.66 ± 0.05 for autograft, is close to 0.6, the value measured in healthy nerves. In contrast, BC implants elicited a strong host response and infiltrating tissue occluded the conduits preventing the formation of myelinated axons. Therefore, although gelatin promotes in vitro nerve regeneration, we conclude that bi-component electrospun conduits are not satisfactory in vivo due to intrinsic limits to their mechanical performance and degradation kinetics, which are essential to peripheral nerve regeneration in vivo.
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Affiliation(s)
- Valentina Cirillo
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy (IPCB-CNR), Viale Kennedy 54, Naples 80125, Italy; Department of Chemical, Materials and Industrial Production Engineering (DICMAPI), University of Naples Federico II, P.leTecchio 80, Naples 80125, Italy
| | - Basak A Clements
- New Jersey Center for Biomaterials, Rutgers - The State University of NJ, 145 Bevier Road, Piscataway, NJ 08854, USA
| | - Vincenzo Guarino
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy (IPCB-CNR), Viale Kennedy 54, Naples 80125, Italy.
| | - Jared Bushman
- New Jersey Center for Biomaterials, Rutgers - The State University of NJ, 145 Bevier Road, Piscataway, NJ 08854, USA
| | - Joachim Kohn
- New Jersey Center for Biomaterials, Rutgers - The State University of NJ, 145 Bevier Road, Piscataway, NJ 08854, USA
| | - Luigi Ambrosio
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy (IPCB-CNR), Viale Kennedy 54, Naples 80125, Italy
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82
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Bartsch I, Willbold E, Rosenhahn B, Witte F. Non-invasive pH determination adjacent to degradable biomaterials in vivo. Acta Biomater 2014; 10:34-9. [PMID: 24021229 DOI: 10.1016/j.actbio.2013.08.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/01/2013] [Accepted: 08/29/2013] [Indexed: 01/07/2023]
Abstract
An appropriate pH level is an important prerequisite for the physiologal functioning of cells and tissues. Changes in the extracellular pH often lead to specific cellular reactions and an altered metabolism of cells and tissues influences the extracellular pH range. Thus a method to monitor the extracellular pH is a valuable tool to track specific tissue reactions. In this article we describe a method for the determination of the pH range adjacent to degradable biomaterials using wireless in vivo imaging. Using hairless but immunocompetent mice the fluorophor 5-(6)-carboxy SNARF-1 and the in vivo fluorescence and multispectral acquisition and analysis system Maestro it is possible to track shifts in pH in small living animals over a longer period of time. This method is especially suitable for studies which focus on the interaction of degrading biomaterials with their adjacent tissues.
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Affiliation(s)
- Ivonne Bartsch
- Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany
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83
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Roffi A, Filardo G, Kon E, Marcacci M. Does PRP enhance bone integration with grafts, graft substitutes, or implants? A systematic review. BMC Musculoskelet Disord 2013; 14:330. [PMID: 24261343 PMCID: PMC3870962 DOI: 10.1186/1471-2474-14-330] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 11/04/2013] [Indexed: 01/07/2023] Open
Abstract
Background Several bone implants are applied in clinical practice, but none meets the requirements of an ideal implant. Platelet-rich plasma (PRP) is an easy and inexpensive way to obtain growth factors in physiologic proportions that might favour the regenerative process. The aim of this review is to analyse clinical studies in order to investigate the role of PRP in favouring bone integration of graft, graft substitutes, or implants, and to identify the materials for which the additional use of PRP might be associated with superior osseo- and soft tissues integration. Methods A search on PubMed database was performed considering the literature from 2000 to 2012, using the following string: ("Bone Substitutes"[Mesh] OR "Bone Transplantation"[Mesh] OR "Bone Regeneration"[Mesh] OR "Osseointegration"[Mesh]) AND ("Blood Platelets"[Mesh] OR "Platelet-Rich Plasma"[Mesh]). After abstracts screening, the full-texts of selected papers were analyzed and the papers found from the reference lists were also considered. The search focused on clinical applications documented in studies in the English language: levels of evidence included in the literature analysis were I, II and III. Results Literature analysis showed 83 papers that fulfilled the inclusion criteria: 26 randomized controlled trials (RCT), 14 comparative studies, 29 case series, and 14 case reports. Several implant materials were identified: 24 papers on autologous bone, 6 on freeze-dried bone allograft (FDBA), 16 on bovine porous bone mineral (BPBM), 9 on β-tricalcium phosphate (β-TCP), 4 on hydroxyapatite (HA), 2 on titanium (Ti), 1 on natural coral, 1 on collagen sponge, 1 on medical-grade calcium sulphate hemihydrate (MGCSH), 1 on bioactive glass (BG) and 18 on a combination of biomaterials. Only 4 papers were related to the orthopaedic field, whereas the majority belonged to clinical applications in oral/maxillofacial surgery. Conclusions The systematic research showed a growing interest in this approach for bone implant integration, with an increasing number of studies published over time. However, knowledge on this topic is still preliminary, with the presence mainly of low quality studies. Many aspects still have to be understood, such as the biomaterials that can benefit most from PRP and the best protocol for PRP both for production and application.
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Affiliation(s)
| | | | - Elizaveta Kon
- Nano-Biotechnology Laboratory, Rizzoli Orthopaedic Institute, Via di Barbiano n 1/10, Bologna 40136, Italy.
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Amini AR, Laurencin CT, Nukavarapu SP. Bone tissue engineering: recent advances and challenges. Crit Rev Biomed Eng 2013; 40:363-408. [PMID: 23339648 DOI: 10.1615/critrevbiomedeng.v40.i5.10] [Citation(s) in RCA: 1331] [Impact Index Per Article: 121.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The worldwide incidence of bone disorders and conditions has trended steeply upward and is expected to double by 2020, especially in populations where aging is coupled with increased obesity and poor physical activity. Engineered bone tissue has been viewed as a potential alternative to the conventional use of bone grafts, due to their limitless supply and no disease transmission. However, bone tissue engineering practices have not proceeded to clinical practice due to several limitations or challenges. Bone tissue engineering aims to induce new functional bone regeneration via the synergistic combination of biomaterials, cells, and factor therapy. In this review, we discuss the fundamentals of bone tissue engineering, highlighting the current state of this field. Further, we review the recent advances of biomaterial and cell-based research, as well as approaches used to enhance bone regeneration. Specifically, we discuss widely investigated biomaterial scaffolds, micro- and nano-structural properties of these scaffolds, and the incorporation of biomimetic properties and/or growth factors. In addition, we examine various cellular approaches, including the use of mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), adult stem cells, induced pluripotent stem cells (iPSCs), and platelet-rich plasma (PRP), and their clinical application strengths and limitations. We conclude by overviewing the challenges that face the bone tissue engineering field, such as the lack of sufficient vascularization at the defect site, and the research aimed at functional bone tissue engineering. These challenges will drive future research in the field.
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Affiliation(s)
- Ami R Amini
- Department of Orthopedic Surgery, University of Connecticut Health Center, Farmington, CT, USA
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85
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Amini AR, Laurencin CT, Nukavarapu SP. Differential analysis of peripheral blood- and bone marrow-derived endothelial progenitor cells for enhanced vascularization in bone tissue engineering. J Orthop Res 2012; 30:1507-15. [PMID: 22378621 DOI: 10.1002/jor.22097] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 02/02/2012] [Indexed: 02/04/2023]
Abstract
For tissue engineering applications, effective bone regeneration requires rapid neo-vascularization of implanted grafts to ensure the survival of cells in the early post-implantation phase. Incorporation of autologous endothelial progenitor cells (EPCs) for the promotion of primitive vascular network formation ex vivo has offered great promise for improved graft survival, enhanced rate of vascularization and bone regeneration in vivo. For clinical usage, identification of an optimal EPC isolation source from the patient is critical. We have, for the first time, characterized and directly compared EPCs from rabbit peripheral blood and bone marrow (PB-EPCs and BM-EPCs, respectively). PB-EPCs outperformed BM-EPCs on all measures. PB-EPCs displayed typical endothelial cell markers, such as CD31, as well as high angiogenic potential in three-dimensional extracellular matrix in vitro. Furthermore, PB-EPCs cultured simultaneously with mesenchymal stem cells, displayed significantly enhanced expression levels of key osteogenic and vascular markers, including alkaline phosphatase, bone morphogenetic protein 2, and vascular endothelial growth factor. On the contrary, putative BM-EPCs did not express CD31, and instead, expressed key smooth muscle markers. BM-EPCs further failed to display vasculogenic activity. Hence, the highly angiogenic PB-derived EPCs may serve as an ideal cell population for enhanced vascularization and success of engineered bone tissue.
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Affiliation(s)
- Ami R Amini
- Institute for Regenerative Engineering, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, Connecticut 06032, USA
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Amini AR, Adams DJ, Laurencin CT, Nukavarapu SP. Optimally porous and biomechanically compatible scaffolds for large-area bone regeneration. Tissue Eng Part A 2012; 18:1376-88. [PMID: 22401817 DOI: 10.1089/ten.tea.2011.0076] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Large-area or critical-sized bone defects pose a serious challenge in orthopedic surgery, as all current treatment options present with shortcomings. Bone tissue engineering offers a more promising alternative treatment strategy. However, this approach requires mechanically stable scaffolds that support homogenous bone formation throughout the scaffold thickness. Despite advances in scaffold fabrication, current scaffold-based techniques are unable to support uniform, three-dimensional bone regeneration, and are limited to only the scaffold surface in vitro and in vivo. This is mainly because of inadequate scaffold pore sizes (<200 μm) and accessible pore volume, and the associated limited oxygen diffusion and vascular invasion. In this study, we have adopted a method combining microsphere-sintering and porogen-leaching techniques to fabricate scaffolds with an increased accessible pore volume. Of the scaffolds developed, moderately porous poly(85 lactide-co-15 glycolide) (PLGA) microsphere scaffolds were selected as most advantageous, since they retain mechanical strength in the range of human cancellous bone and display a significantly higher accessible pore volume, which is attributed to an increased percentage of larger pores (i.e., size range 200-600 μm). Unlike control scaffolds with a limited pore size and an accessible pore volume, moderately porous scaffolds displayed increased oxygen diffusion, pre-osteoblast cell infiltration, proliferation, and survival throughout the entire scaffold. Furthermore, moderately porous PLGA microsphere scaffolds displayed enhanced and homogenous mineralization in vitro. Since these newly designed moderately porous scaffolds are weight bearing, are fully osteoconductive, and have the ability to support vascularization, they may serve as effective scaffolds for large-area bone defect repair/regeneration. In addition, this study demonstrates the ability to modulate scaffold porosity and, in turn, to develop oxygen tension-controlled matrices that are effective for large-area bone regeneration.
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Affiliation(s)
- Ami R Amini
- Institute for Regenerative Engineering, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 06030, USA
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Musib M, Saha S. Nanostructured materials for bone tissue replacement. Nanomedicine (Lond) 2012. [DOI: 10.1533/9780857096449.4.599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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