Water-induced shape-memory poly(d,l-lactide)/microcrystalline cellulose composites

• Water-induced shape memory composite was successfully fabricated.
• The transition temperature was adjusted to body temperature (37 °C) by simply changing the composite ratio.
• The composite possesses good biocompatibility.

Thermo-induced shape-memory polymers (SMPs) have been widely investigated, but their biomedical applications are limited because their switching temperature does not fall completely within the range of room temperature to body temperature. In this study, we prepared water-induced shape-memory composites composed of microcrystalline cellulose (MCC) and poly(d,l-lactide) (PDLLA). We observed that the composite with an MCC content of 35% (PDLLA-MCC-35) exhibited a good shape-memory effect upon exposure to water at 37 °C. We also analyzed the mechanism of the water-triggered shape-memory effect by considering the microstructure, water contact angle, water uptake, thermal properties and static and dynamic mechanical properties of the composite. The results of in vitro degradation analysis demonstrate that the composites exhibited good biodegradation. In addition, Alamar blue assays based on osteoblasts indicate that the composites possess good cytocompatibility. Therefore, the water-induced shape-memory composite can potentially be developed into a new smart medical device.