Shape-memory anchoring system for bladder sensors

In this work, we propose the use of shape-memory polymer as an anchoring system for a bladder sensor. The anchoring system was designed from a biomedical biodegradable water-based poly(ester-urethane) produced in an aqueous environment by using isophorone diisocyanate/hydrazine (hard segment) and poly(caprolactone diol)/2,2-bis (hydroxymethyl) propionic acid (soft segment) as the main reagents. Tensile strength and elongation-at-break deterioration upon degradation in synthetic urine were investigated. In-body shape recovery was simulated and measured in synthetic urine. Results indicated that shape recovery can occur at body temperature and expulsion of the sensor by the body along with urine may occur through the combined effect of urine hydrolytic attack and compression exerted by the bladder walls. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 96B: 369-375, 2011.