Understanding the biodegradation of polyurethanes: From classical implants to tissue engineering materials
Section snippets
Chemistry of PUs
The nature of PU chemistry is central to understanding why some PUs undergo degradation faster than others. For this reason a brief review of the material chemistry is needed prior to discussing PU degradation. Segmented PUs can be represented by three basic components described by the following general form:where P is the polyol, D is the diisocyanate and C is the chain extender. Typically, the polyol, or the so-called soft segment, is an oligomeric macromonomer comprising a
Molecular reactions between biological agents and PUs
Early observations relating to the biodegradation of PUs raised much controversy around the pathways leading to the process. This resulted in good part from the lack of understanding associated with the molecular mechanisms contributing to the cleavage of the polymer chains. It was the work of Ken Stokes, which initially provided the most comprehensive theory of in vivo biodegradation in his description of ESC [2], [4], [5], [6], [7]. This explanation of the biodegradation process was adopted
PU degradation and inflammatory cells
As highlighted in the previous section in the description of EB, it is the white blood cell and more specifically the MDM that has emerged as the predominant cell type that is orchestrating the damage in biodegradation processes [44]. But it must be clearly stated that the macrophage takes its cue from the presence of the material and its unique chemistry. Work by Marchant and colleagues quantitatively determined the cellular composition of the inflammatory exudates surrounding the implanted
Design of biodegradable PUs for the in vivo environment
While traditionally investigators have used PUs as long-term implant materials [92] and have attempted to shield them from the biodegradation processes that were described in the previous sections of this review, more recent work by investigators has utilized the flexible chemistry and diverse mechanical properties of PU materials to design degradable polymers for applications as varied as neural conduits [93] to bone replacements [94]. These materials have for the most part taken advantage of
Summary
With knowledge, new opportunity is almost always found. This review of literature presented biomedical PUs from their early conceptual design through events that at one time cast the future of PUs into doubt. However, through careful analysis of the EB mechanisms a better understanding of the materials and their behaviour in vivo has been acquired. While new and more bioresistant formulations of PUs have been conceived the area of biodegradable PUs is poised to make significant strides within
Acknowledgements
The authors wish to thank the editors of the Biomaterials journal and the Board of Directors for the Canadian Biomaterials Society for having provided the authors with this unique opportunity to convey International and Canadian developments occurring in the area of PU biodegradation.
References (117)
- et al.
Polyether polyurethanes for implantable pacemaker leads
Biomaterials
(1982) - et al.
Lysosomal enzyme release from human neutrophils adherent to biomaterial surfaces: an in vitro model of biocompatibility
Cardiov Pathol
(1997) - et al.
Effect of hard segment chemistry and strain on the stability of polyurethanes: in-vivo stability
Biomaterials
(1993) - et al.
Detection and identification of biodegradation products from polycarbonate–polyurethanes
Biomaterials
(2003) Degradation of polyurethanes in biomedical applications—a review. Polymer degradation and stability
(1991)- et al.
The influence of protein adsorption and surface modifying macromolecules on the hydrolytic degradation of a poly(ether-urethane) by cholesterol esterase
Biomaterials
(2003) Characterization of human neutrophils adherent to organic polymers
Biomaterials
(1995)- et al.
Role of leucocytes in coagulation induced by artificial surfaces: investigation of expression of Mac-1, granulocyte elastase release and leucocyte adhesion on modified polyurethanes
Biomaterials
(1996) - et al.
Hydrolytic degradation of poly(carbonate)-urethanes by monocyte-derived macrophages
Biomaterials
(2001) - et al.
Modified low density lipoprotein enhances the secretion of bile salt-stimulated cholesterol esterase by human monocyte-macrophages. species-specific difference in macrophage cholesteryl ester hydrolase
J Biol Chem
(1997)
Human monocyte carboxylesterase. Purification and kinetics
J Biol Chem
Human macrophage-mediated biodegradation of polyurethanes: assessment of candidate enzyme activities
Biomaterials
Studies on the effect of surface properties on the biocompatibility of polyurethane membranes
Biomaterials
A new peptide-based urethane polymer:synthesis degradation and potential to support cell growth in vitro
Biomaterials
Synthesis and characterization of a novel biodegradable antimicrobial polymer
Biomaterials
Interaction of organic solvents with polyurethane
J Macromol Sci
Polyurethane elastomer biostability
J Biomater Appl
Biomedical applications of polyurethanes: implications of failure mechanisms
J Biomater Appl
New test methods for the evaluation of stress cracking and metal catalyzed oxidation in implanted polymers
Autooxidative degradation of implanted polyether polyurethane devices
J Biomater Appl
The in vivo auto-oxidation of polyether polyurethane by metal ions
J Biomater Sci Polym Ed
The enzymatic degradation of polymers in vitro
J Biomed Mater Res
Interactions of hydrolytic enzymes at an aqueous-polyurethane interface. Proteins at interfaces II
J Am Chem Soc
Biomaterial-associated calcification: pathology, mechanism, and strategies for prevention
J Biomed Mater Res
XPS study of surface composition of a segmented polyurethane block copolymer modified by PDMS end groups and its blends with phenoxy
Macromolecules
Degradation of explanted polyurethane cardiac pacing leads and of polyurethane
Biomater Artif Cells Artif Organs
In vitro function and durability assessment of a novel polyurethane heart valve prosthesis
Artif Organs
The hydrolytic stability of mitrathane (a polyurethane urea) an X-ray photoelectron spectroscopy study
J Biomed Mater Res
Electron and light microscopy examination of capsules around breast implants
Plast Reconstr Surg
The capsule quality of saline-filled smooth silicone, textured silicone, and polyurethane implants in rabbits: a long-term study
Plast Reconstr Surg
Disappearance of the polyurethane cover of the ashley natural y prosthesis
Plast Reconstr Surg
Model systems to assess the destructive potential of human neutrophils and monocyte-derived macrophages during the acute and chronic phases of inflammation
J Biomed Mater Res
Mechanisms of inflammation and infection with implanted devices
Cardiovasc Pathol
In vivo biocompatibility studies. In vivo leukocyte interactions with Biomer
J Biomed Mater Res
Human plasma α-macroglobulin promotes in vitro oxidative stress cracking of Pellethane 2363–80A: in vivo and in vitro correlations
J Biomed Mater Res
Degradation of polyurethane foams used in the Meme breast implant
J Biomed Mater Res
An assessment of 2,4-TDA formation from Surgitek polyurethane foam under simulated physiological conditions
J Biomater Appl
Determination of extractable methylene dianiline in thermoplastic polyurethanes by HPLC
J Biomed Mater Res
Carcinogenicity and chronic toxicity of 2,4-toluenediamine in F344 rats
J Natl Cancer Inst
Carcinogenic and chronic effects of 4,4′-diamino-diphenyl methane, an epoxy resin hardener
Nature
Toxic hydrolysis product from biodegradable foam implant
J Biomed Mater Res
Biodegradation of a poly(ester)urea-urethane by cholesterol esterase: Isolation and identification of principal biodegradation products
J Biomed Mater Res
Probing the surface chemistry of a hydrated segmented polyurethane and a comparison with its dry surface chemical structure
Macromolecules
The biodegradation of poly(urethane)s by the esterolytic activity of serine proteases
J Biomater Sci Polym Ed
The effect of hard segment size on the hydrolytic stability of polyether-urea-urethanes when exposed to cholesterol esterase
J Biomed Mater Res
The use of silicone/polyurethane graft polymers as a means of eliminating surface stress cracking of polyurethane prothesis
J Biomater Appl
Thermoplastic polyurethanes as insulating materials for long-life cardiac pacing leads
Pace
In vivo degradation of a polyurethane: preclinical studies
Polyurethanes in medicine
Cited by (641)
Electrospun methacrylated natural/synthetic composite membranes for gingival tissue engineering
2024, Acta BiomaterialiaAn overview of polyurethane biomaterials and their use in drug delivery
2023, Journal of Controlled ReleaseExploring structure-activity relationships for polymer biodegradability by microorganisms
2023, Science of the Total EnvironmentArrhenius-model-based degradable oligourethane hydrogels for controlled growth factor release
2023, Acta Biomaterialia