Shape-memory starch for resorbable biomedical devices.

Shape-memory resorbable materials were obtained by extrusion-cooking of potato starch with 20% glycerol under usual conditions. They presented an efficient shape-memory with a high recovery ratio (Rr>90%). Their recovery could be triggered at 37°C in water. After water immersion at 37°C, the modulus decreased from 1GPa to 2.4MPa and remained almost constant over 21 days. Gamma-ray sterilization did not have a dramatic impact on their mechanical properties, despite a large decrease of molecular mass analyzed by asymmetrical flow field-flow fractionation coupled with multi-angle laser light scattering (AFFFF-MALLS). Samples implanted in a rat model exhibited normal tissue integration with a low inflammatory response. Thus, as previously investigated in the case of shape-memory synthetic polymers, natural starch, without chemical grafting, can now be considered for manufacturing innovative biodegradable devices for less-invasive surgery.