An investigation of the in vivo stability of poly(ether urethaneurea) blood sacs

In this paper we investigate the biostability of a series of Biolon blood sacs that were utilized in electric total artificial hearts for time periods of up to 19 weeks. A battery of experimental probes, including scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), were used to characterize the bulk and surface properties of explanted and control blood sacs. Gel permeation chromatography (GPC) experiments showed that generally there was a dramatic increase in average molecular weight at longer implantation times. However, SEM and GPC observations suggest significant deterioration of the flex regions of right blood sacs after 17 weeks of service. XPS experiments indicated appreciable silicon and hydrocarbon concentrations on blood-contacting surfaces both before and after implantation, and we speculate as to their origin.