Biostability of Polyurethane Elastomers: A Critical Review

Szycher, Michael

doi:10.1177/088532828800300207

Cited by 183 publications

(91 citation statements)

References 13 publications

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“…Nevertheless, its degradation rate is significantly lower than that of most degradable materials used for tissue engineering applications (e.g., polyglycolic acid and polylactic-coglycolic acid). 18,19 Another reason against degradable scaffolds is the high pressure stress in aortic position, meaning that proper function and a high life expectancy cannot be guaranteed. 20,21 Under these conditions, just decellularized homografts showed a promising in vivo short-and mid-term performance.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Comparison of Novel Polyurethane Aortic Valves and Homografts After Seeding and Conditioning

Thierfelder

Koenig²,

Bombien

et al. 2013

ASAIO Journal

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The aim of the study was to compare the behavior of seeded cells on synthetic and natural aortic valve scaffolds during a low-flow conditioning period. Polyurethane (group A) and aortic homograft valves (group B) were consecutively seeded with human fibroblasts (FB), and endothelial cells (EC) using a rotating seeding device. Each seeding procedure was followed by an exposure to low pulsatile flow in a dynamic bioreactor for 5 days. For further analysis, samples were taken before and after conditioning. Scanning electron microscopy showed confluent cell layers in both groups. Immunohistochemical analysis showed the presence of EC and FB before and after conditioning as well as the establishment of an extracellular matrix (ECM) during conditioning. A higher expression of ECM was observed on the scaffolds' inner surface. Realtime polymerase chain reaction showed higher inflammatory response during the conditioning of homografts. Endothelialization caused a decrease in inflammatory gene expression. The efficient colonization, the establishment of an ECM, and the comparable inflammatory cell reaction to the scaffolds in both groups proved the biocompatibility of the synthetic scaffold. The newly developed bioreactor permits conditioning and cell adaption to shear stress. Therefore, polyurethane valve scaffolds may offer a new option for aortic valve replacement. ASAIO Journal 2013;59:309-316.

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Section: Discussionmentioning

confidence: 99%

In Vitro Comparison of Novel Polyurethane Aortic Valves and Homografts After Seeding and Conditioning

Thierfelder

Koenig²,

Bombien

et al. 2013

ASAIO Journal

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“…Polyurethanes have been used in medical devices since the 1970s and the literature has reported on the biostability of polyurethanes [20][21][22][23][24][25]. Generally, the biostability of polyurethanes is strongly affected by multiple factors.…”

Section: Discussionmentioning

confidence: 99%

“…For example, polycarbonate soft segments are chemically more stable than either polyether or polyester counterparts and the biostability of a Shore 55D polyurethane is quite different from that of Shore 80A one [25]. The annealing process reduces environmental stress cracking (ESC) [20][21][22][23] while appropriate sterilization methods maintain the biostability of polyurethanes [20]. Bulky and dense polyurethanes are more stable than thin, porous or fibrous polyurethanes [22].…”

Section: Discussionmentioning

confidence: 99%

“…Biodegradation of a supposedly biostable material or component will result in undesirable chemical, mechanical, and biological responses. The biostability and mechanical performance of polymeric implant components correlate to each other via molecular weight [20]. Biostable polymeric components with stable molecular chemistry and structures provide stable molecular weight of polymers, which in turn maintains the as-designed and appropriate mechanical performance of the implants.…”

Section: Discussionmentioning

confidence: 99%

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In vivo biostability of polymeric spine implants: retrieval analyses from a United States investigational device exemption study

Shen¹,

Zhang²,

Koettig

et al. 2011

Eur Spine J

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The Dynesys System for stabilizing the lumbar spine was first surgically implanted in Europe in 1994. In 2003, a prospective, randomized, investigational device exemption clinical trial of the system for non-fusion dynamic stabilization began. Polycarbonate urethane (PCU) and polyethylene terephthalate (PET) components explanted from four patients who had participated in the study were analyzed for biostability. Components had been implanted 9-19 months. The explanted components were visually inspected and digitally photographed. Scanning electron microscopy was used to analyze the surface of the spacers. The chemical and molecular properties of the retrieved spacers and cords were quantitatively compared with lot-matched, shelf-aged, components that had not been implanted using attenuated total reflection Fourier transform infrared (FTIR) and gel permeation chromatography (GPC). FTIR analyses suggested that the explanted spacers exhibited slight surface chemical changes but were chemically unchanged below the surface and in the center. New peaks that could be attributed to biodegradation of PCU were not observed. The spectral analyses for the cords revealed that the PET cords were chemically unchanged at both the surface and the interior. Peaks associated with the PET biodegradation were not detected. GPC results did not identify changes to the distributions of molecular weights that might be attributed to biodegradation of either PCU spacers or PET cords. The explanted condition of the retrieved components demonstrated the biostability of both PCU spacers and PET cords that had been in vivo for up to 19 months.

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“…Polyether TPUs are hydrolytically stable yet they can undergo oxidative degradation in several forms including oxidation and environmental stress in the in vivo environment [1,7,8]. A common type of medical grade TPU is pellethane, which has been widely used as a biomaterial since its introduction in 1977 [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

The influence of electron-beam irradiation on the chemical and the structural properties of medical-grade polyurethane

Shin

Lee

2015

Journal of the Korean Physical Society

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Thermo plastic polyurethane (TPU) provides excellent bio-compatibility, flexibility and good irradiation resistance; however, extremely high irradiation doses can alter the structure and function of macromolecules, resulting in oxidation, chain scission and cross-linking. In this study, the effects of e-beam irradiation on the medical grade thermo plastic polyurethane were studied. The changes in the chain length and their distribution as well as the changes in molecular structure were studied. The GPC (Gel Permeation Chromatography) results show that the oxidative decomposition is followed by a decrease in molecular mass together with an increase in polydispersity. This indicates a very inhomogeneous degradation, which is a consequence of the specific course and of the intensity of oxidative degradation. This was confirmed by means of mechanical property measurements. Overall, this study demonstrated that the medical grade TPU was affected by radiation exposure, particularly at high irradiation doses.PACS numbers: 61.82.Pv

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Biostability of Polyurethane Elastomers: A Critical Review

Cited by 183 publications

References 13 publications

In Vitro Comparison of Novel Polyurethane Aortic Valves and Homografts After Seeding and Conditioning

In Vitro Comparison of Novel Polyurethane Aortic Valves and Homografts After Seeding and Conditioning

In vivo biostability of polymeric spine implants: retrieval analyses from a United States investigational device exemption study

The influence of electron-beam irradiation on the chemical and the structural properties of medical-grade polyurethane

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