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Published February 2021 | Supplemental Material + Published
Journal Article Open

Assessment of a Siloxane Poly(urethane‐urea) Elastomer Designed for Implantable Heart Valve Leaflets


Synthetic polymer leaflets in prosthetic cardiac valves hold the potential to reduce calcification and thrombus, while improving blood flow, durability, and device economics. A recently developed siloxane poly(urethane‐urea) (LifePolymer, LP) exhibits properties essential for heart valve leaflets, including low dynamic modulus, high tensile strength, minimal creep, and excellent biostability. LP's properties result from carefully designed "linked co‐macrodiol" chemistry that maximizes silicone content and virtual crosslinks between soft and hard phases. Characterization of multiple commercial batches demonstrates a robust synthesis process with minimal variation. Extensive ISO 10993–based biocompatibility testing results in no observable toxicity or other adverse reactions. An ex vivo AV shunt thrombogenicity investigation reveals nearly undetectable levels of platelet attachment and thrombus formation on LP surfaces. Chronic ovine implantation of prototype heart valves with LP leaflets shows no differences in thrombogenicity or systemic tissue response when compared to a clinically standard tissue‐based valve. Toxicological risk assessment, based on extractables and leachables analysis of LP‐based heart valves, confirms minimal toxicological risk. Lastly, 24‐week, strain‐accelerated in vivo LP biostability testing confirms previous favorable in vitro biostability findings. These studies demonstrate that this newly developed elastomer exhibits ideal biomaterial properties for the flexible leaflets of a totally synthetic heart valve replacement.

Additional Information

© 2020 The Authors. Advanced NanoBiomed Research published by Wiley‐VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Issue Online: 05 February 2021; Version of Record online: 21 December 2020; Accepted manuscript online: 26 November 2020; Manuscript revised: 29 October 2020; Manuscript received: 11 September 2020. The authors thank Tony Rowe and Meg Evans at the Commonwealth Scientific and Industrial Research Organization (North Ryde, NSW, Australia) for their efforts during the in‐life portion of the rabbit study. Thanks to Randy D. White at Preclintox Services, LLC (Hyrum, UT) and Mark Jordi at JordiLabs, LLC (Mansfield, MA) for their extensive work on the extractables and leachables toxicological assessment. Finally, the authors acknowledge both the American Preclinical Services (Minneapolis, MN) and WuXi AppTec (St. Paul, MN) for the completion of multiple biocompatibility testing protocols. This research was funded in its entirety by Foldax, Inc., Salt Lake City, UT, USA. The Conflict of Interest statement was corrected on February 08, 2021 after initial publication online. Conflict of Interest: All authors are either consultants to or employees of Foldax, Inc.

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Published - anbr.202000032.pdf

Supplemental Material - anbr202000032-sup-0001-suppdata-s1.docx


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August 22, 2023
October 23, 2023