Shape memory scaffold with a tunable recovery temperature for filling critical-size bone defects

Traditionally, critical-size defects have been treated using autologous bone grafts which, while being effective, have limitations that include donor site scarcity, additional pain, and donor site morbidity. Synthetic scaffolds show promise as alternate graft materials, but current scaffolds have limitations associated with filling and conforming to the defect site. In this study, we aimed to synthesize a cytocompatible scaffold with shape memory functionality that could address limitations associated with filling and conforming to the defect site. To achieve this goal we employed a porogen-leaching technique to fabricate a shape memory poly(epsilon- caprolactone) (PCL) foam capable of expanding to fill space under physiological temperatures. Tuning of the recovery temperature to a physiological temperature was achieved by copolymerizing with a second, hydrophilic polymer, as well as by varying the deformation temperature. The scaffold showed excellent shape fixing and shape recovery, and the transition temperature was tuned to a physiological range. Preliminary cell studies showed qualitatively that cells remain viable and proliferate on the scaffold.