Surface modification and in vitro blood compatibilities of polyurethanes containing z‐lysine segments in the main chain

Abstract

Polyurethanes containing z-lysine segments in the main chain (PULL) were synthesized from 4,4Ј-diphenylmethyl diisocyanate, poly(tetramethylene glycol), and zlysine oligomer as a chain extender. PULL film was treated with a 10% HBr-acetic acid solution and subsequently with a saturated sodium bicarbonate aqueous solution to produce a primary amine group on the surface. Heparin-immobilized PULL (PULL-H) was prepared by the coupling reaction of PULL surface amine groups and heparin carboxylic acid groups. The surface-modified PULLs were then characterized by attenuated total reflection-Fourier transform infrared spectroscopy, electron spectroscopy for chemical analysis, and a contact angle goniometer. The concentration of amine groups and heparins introduced on the PULL sur-faces were about 2.1 mol/cm 2 and 1.9 g/cm 2 , respectively. To assess in vitro blood compatibility, the interaction of modified PULLs with plasma proteins and platelets was examined. In the experiments with plasma proteins, plasma recalcification time and activated partial thromboplastin time were significantly prolonged on PULL-H compared to those on the other surfaces. The percentage of serotonin released from platelets adhering on PULL-H was less than that on the other surfaces, demonstrating a good in vitro blood compatibility.

Morphology and physical properties of a novel Ramie‐PU blended nonwoven by electrospinning: The effect of cosolvent ratio

“…In this work, we attempted to improve the physical properties (in particular, the tensile strength and flexibility) of ramie web supplied by Shiga Ramie Industry Co. via electrospinning polyurethane (PU), a well‐known resilient elastomer that is widely used in coatings, sealants and transdermal patches,19–22 into nanofibers and covering the surface of the ramie webs. PU has been extensively investigated with respect to potential application as a biomaterial in scaffoldings and wound dressings,23–27 because of its excellent elasticity, high tensile strength, good biocompatibility, and antithrombogenicity due to its microphase separation induced by blocking hard and soft segments. Recently, PU has been electrospun, primarily to combine its intrinsic properties, such as high elasticity and flexibility, with the advantages of nanofibers 28–33.…”