Browsing by Author "Thomas, Vinoy"

Now showing 1 - 2 of 2
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    A new generation of high flex life polyurethane urea for polymer heart valve-Studies on in vivo biocompatibility and biodurability
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, 2009)
    Development of new generation high flex life polyurethane urea (HFL18-PU) with appropriate elastic modulus, biocompatibility, blood compatibility, resistant to calcification, and biodurability for the long-term use as cardiac device is still a challenge. This study reports the development of a fully aliphatic, ether-free physically cross-linked and low elastic modulus (6.841 +/- 0.27 MPa) polyurethane urea having hi vivo biostability, in vivo biocompatibility and high flex-life (721 +/- 30 million cycles) that can satisfy the requirements for the fabrication of tri-leaflet heart valve. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 89A: 192-205, 2009
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    Biomechanical studies on aliphatic physically crosslinked poly(urethane urea) for blood contact applications
    (JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 2008)
    Hydrophobic and physically crosslinked (virtually crosslinked through hydrogen bonding) aliphatic poly(urethane urea)s were developed and characterized for its biomechanical properties. The aging under induced-stress (bend samples) condition reveals resistance of poly(urethane urea) to environmental stress corrosion cracking (ESC) in hydrolytic media, Ringer's solution and phosphate buffered saline at 50 degrees C. The strain-induced (20% tensile strain) and aged polymer in hydrolytic enzyme medium, papain and in buffer reveals increase of elastic modulus in papain enzyme and papain buffer. The increase of elastic modulus is attributed to unidirectional reorganisation of chains under continually strained conditions. The polymer exposed in boiling alcoholic potassium hydroxide solution (accelerated hydrolytic chemical degradation) reveals no degradation. A comparative evaluation of poly(ether urethane urea)s reveals inferior properties. Poly(ether urethane urea)s polymer undergo hydrolytic degradation in boiling alcoholic potassium hydroxide solution. The candidate poly(urethane urea) HFL 18-PUU is more promising elastomer for long-term biomechanically sensitive blood contact applications such as heart valve and blood pump diaphragm of left ventricular assist device.