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Gasson SB, Dobson LK, Pfau-Cloud MR, Beltran FO, Pool RR, Gregory CA, Grunlan MA, Saunders WB. Biocompatibility and Bone Regeneration by Shape Memory Polymer Scaffolds. J Biomed Mater Res A 2025; 113:e37806. [PMID: 39404147 DOI: 10.1002/jbm.a.37806] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 09/19/2024] [Accepted: 09/23/2024] [Indexed: 12/26/2024]
Abstract
Biodegradable, shape memory polymer (SMP) scaffolds based on poly(ε-caprolactone) (PCL) offer unique advantages as a regenerative treatment strategy for critical-sized bone defects. In particular, a conformal fit may be achieved following exposure to warm saline, thereby improving osseointegration and regeneration. Advancing the clinical translation of these SMP scaffolds requires establishment of efficacy not only in non-loading models, but also load-bearing or load-sharing models. Thus, the present study evaluated the biocompatibility and bone regeneration potential of SMP scaffolds in a rabbit distal femoral condyle model. Two distinct SMP scaffold compositions were evaluated, a "PCL-only" scaffold formed from PCL-diacrylate (PCL-DA) and a semi-interpenetrating network (semi-IPN) formed from PCL-DA and poly(L-lactic acid) (PCL:PLLA). Semi-IPN PCL:PLLA scaffolds possess greater rigidity and faster rates of degradation versus PCL scaffolds. In vivo biocompatibility was assessed with a rat subcutaneous implantation model, whereas osseointegration was assessed with a 4 mm × 8 mm rabbit distal femoral condyle defect model. Both types of SMP scaffolds exhibited excellent biocompatibility marked by infiltration with fibrous tissue and a minimal inflammatory response. When implanted in the rabbit distal femur, both SMP scaffolds supported bone ingrowth. Collectively, these results demonstrate that the SMP scaffolds are biocompatible and integrate with adjacent host osseous tissues when implanted in vivo in a load-sharing environment. This study provides key proof-of-concept data necessary to proceed with large animal translational studies and clinical trials in human subjects.
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Affiliation(s)
- Shelby B Gasson
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Lauren K Dobson
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Michaela R Pfau-Cloud
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, Texas, USA
| | - Felipe O Beltran
- Department of Materials Science & Engineering, College of Engineering, Texas A&M University, College Station, Texas, USA
| | - Roy R Pool
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Carl A Gregory
- Department of Molecular & Cellular Medicine, Institute for Regenerative Medicine, Texas A&M Health Science Center, College Station, Texas, USA
| | - Melissa A Grunlan
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, Texas, USA
- Department of Materials Science & Engineering, College of Engineering, Texas A&M University, College Station, Texas, USA
- Department of Chemistry, College of Engineering, Texas A&M University, College Station, Texas, USA
| | - W Brian Saunders
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
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Fischer A, Telouk P, Beckmann C, Heermant S, Wittrock A, Debus J, Wimmer MA. Performance of Austenitic High-Nitrogen Steels under Gross Slip Fretting Corrosion in Bovine Serum. J Funct Biomater 2024; 15:110. [PMID: 38667567 PMCID: PMC11051106 DOI: 10.3390/jfb15040110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Modular artificial hip joints are a clinical standard today. However, the release of wear products from the head-taper interface, which includes wear particles in the nm size range, as well as metal ions, have raised concerns. Depending on the loading of such taper joints, a wide variety of different mechanisms have been found by retrieval analyses. From these, this paper concentrates on analyzing the contribution of gross slip fretting corrosion at ultra-mild wear rates using a bovine calf serum solution (BCS) as the lubricant. The parameters were chosen based on biomechanical considerations, producing wear rates of some ng/m wear path. In parallel, the evolution of tribomaterial (third bodies) was analyzed as to its constituents and generation rates. It has already been shown earlier that, by an advantageous combination of wear mechanisms and submechanisms, certain constituents of the tribomaterial remain inside the contact area and act like extreme-pressure lubricant additives. For the known wear and corrosion resistance of austenitic high-nitrogen steels (AHNSs), which outperform CoCrMo alloys even under inflammatory conditions, we hypothesized that such steels will generate ultra-mild wear rates under gross slip fretting. While testing AHNSs against commercially available biomedical-grade materials of CoCrMo and TiAlV alloys, as well as zirconia-toughened alumina (ZTA) and against itself, it was found that AHNSs in combination with a Ti6Al4V alloy generated the smallest wear rate under gross slip fretting corrosion. This paper then discusses the wear behavior on the basis of ex situ analyses of the worn surfaces as to the acting wear mechanisms and submechanisms, as well as to the tribological reaction products.
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Affiliation(s)
- Alfons Fischer
- Max Planck Institute for Sustainable Materials, Microstructure Physics and Alloy Design, 40237 Duesseldorf, Germany
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612, USA;
| | - Philipe Telouk
- Laboratoire de Géologie, Université de Lyon, 69342 Lyon, France;
| | - Christian Beckmann
- Department of Physics, TU Dortmund University, 44227 Dortmund, Germany; (C.B.); (S.H.); (A.W.); (J.D.)
| | - Saskia Heermant
- Department of Physics, TU Dortmund University, 44227 Dortmund, Germany; (C.B.); (S.H.); (A.W.); (J.D.)
| | - Adrian Wittrock
- Department of Physics, TU Dortmund University, 44227 Dortmund, Germany; (C.B.); (S.H.); (A.W.); (J.D.)
| | - Jörg Debus
- Department of Physics, TU Dortmund University, 44227 Dortmund, Germany; (C.B.); (S.H.); (A.W.); (J.D.)
| | - Markus A. Wimmer
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612, USA;
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Klíma K, Ulmann D, Bartoš M, Španko M, Dušková J, Vrbová R, Pinc J, Kubásek J, Vlk M, Ulmannová T, Foltán R, Brizman E, Drahoš M, Beňo M, Machoň V, Čapek J. A Complex Evaluation of the In-Vivo Biocompatibility and Degradation of an Extruded ZnMgSr Absorbable Alloy Implanted into Rabbit Bones for 360 Days. Int J Mol Sci 2021; 22:ijms222413444. [PMID: 34948238 PMCID: PMC8706155 DOI: 10.3390/ijms222413444] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 12/27/2022] Open
Abstract
The increasing incidence of trauma in medicine brings with it new demands on the materials used for the surgical treatment of bone fractures. Titanium, its alloys, and steel are used worldwide in the treatment of skeletal injuries. These metallic materials, although inert, are often removed after the injured bone has healed. The second-stage procedure—the removal of the plates and screws—can overwhelm patients and overload healthcare systems. The development of suitable absorbable metallic materials would help us to overcome these issues. In this experimental study, we analyzed an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. From this alloy we developed screws which were implanted into the rabbit tibia. After 120, 240, and 360 days, we tested the toxicity at the site of implantation and also within the vital organs: the liver, kidneys, and brain. The results were compared with a control group, implanted with a Ti-based screw and sacrificed after 360 days. The samples were analyzed using X-ray, micro-CT, and a scanning electron microscope. Chemical analysis revealed only small concentrations of zinc, strontium, and magnesium in the liver, kidneys, and brain. Histologically, the alloy was verified to possess very good biocompatibility after 360 days, without any signs of toxicity at the site of implantation. We did not observe raised levels of Sr, Zn, or Mg in any of the vital organs when compared with the Ti group at 360 days. The material was found to slowly degrade in vivo, forming solid corrosion products on its surface.
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Affiliation(s)
- Karel Klíma
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Dan Ulmann
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Martin Bartoš
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Michal Španko
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
- Department of Anatomy, 1st Faculty of Medicine, Charles University, 121 08 Prague, Czech Republic
| | - Jaroslava Dušková
- Department of Pathology, 1st Faculty of Medicine, Charles University, 121 08 Prague, Czech Republic;
| | - Radka Vrbová
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Jan Pinc
- Department of Functional Materials, FZU-The Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Prague, Czech Republic;
| | - Jiří Kubásek
- Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague 6, Czech Republic;
| | - Marek Vlk
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Tereza Ulmannová
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - René Foltán
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Eitan Brizman
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Milan Drahoš
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Michal Beňo
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Vladimír Machoň
- Department of Stomatology, General Teaching Hospital, 1st Faculty of Medicine, Charles University, Kateřinská 32, 121 08 Prague, Czech Republic; (K.K.); (D.U.); (M.B.); (M.Š.); (R.V.); (M.V.); (T.U.); (R.F.); (E.B.); (M.D.); (M.B.); (V.M.)
| | - Jaroslav Čapek
- Department of Functional Materials, FZU-The Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Prague, Czech Republic;
- Correspondence:
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