title: In vivo and in vitro stability of modified poly(urethaneurea) blood sacs.
abstract: In the present study, we investigate the in vivo and in vitro stability of modified poly(urethaneurea) (BioSpan MS/0.4) blood sacs. Blood sacs were utilized primarily in left ventricular assist devices that were implanted in calves for times ranging from 5 to 160 days. Cyclic testing in vitro was also conducted on similar sacs. Various analytical methods were employed to characterize the sacs after in vivo or in vitro service and corresponding retained "control" sacs. These methods included ATR-FTIR spectroscopy, scanning electron microscopy and gel permeation chromatography. In general, the characteristics of implanted and in vitro cycled sacs were similar to their control sacs. Thermal and microtensile properties were unchanged after testing. The same was true for the ATR-FTIR spectra, indicating relative chemical stability for the time frames explored here. The only significant changes occurred in molecular weight and gross surface morphology. A modest increase in weight average molecular weight was observed for most implanted blood sacs, indicating some type of chain extension or branching reaction in vivo. Although the surface morphologies of implanted blood sacs were often similar to their control sacs, we sometimes observed limited pitting on the nonblood contacting surfaces in regions of the sac that experience maximum bending during service.
authors.affiliation: Department of Materials Science and Engineering, The Pennsylvania State University, University Park 16802, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Runt
authors.forename: G
authors.initials: G
authors.lastname: Felder
authors.forename: G
authors.initials: G
authors.lastname: Rosenberg
authors.forename: A J
authors.initials: AJ
authors.lastname: Snyder
authors.forename: W J
authors.initials: WJ
authors.lastname: Weiss
authors.forename: J
authors.initials: J
authors.lastname: Lewis
authors.forename: T
authors.initials: T
authors.lastname: Werley
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001673:Biodegradation, Environmental; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D002850:Chromatography, Gel; D006353:Heart-Assist Devices; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D019736:Prostheses and Implants; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D011140:Polyurethanes; C044690:polyetherurethane urea