Design of a Smart Nerve Conduit Based on a Shape-Memory Polymer

The peripheral nervous system (PNS) may be damaged by traffic accidents and natural disasters. Nerve repair and regeneration are unique clinical challenges for surgeons. A smart nerve conduit (SNC) is designed that can significantly simplify the surgery process and achieve optimal peripheral nerve regeneration (PNR) by automatic gradual lengthening. For this purpose, five macromers with different rac-lactide to glycolide weight ratios are synthesized and the characteristics of the synthesized networks are studied. Cyclic thermomechanical measurements indicate the robustness of molecular structure for shape-memory function. Body-water-responsive shape-memory behavior is evaluated by use of angle-recovery measurements. The shape-recovery time of the polymer is adjusted by selection of comonomer ratio and the overall gradual-recovery function of a device can be realized by a suitable combination of different copolymers. Thus a trisegment smart nerve conduit is fabricated from this polymer system by electrospinning and is shown to gradually recover in an in vitro experiment under stimulated physiological conditions, that is, body-liquid environment (36 degrees C water). In vitro culture and qualitative immunocytochemistry of Schwann cells are used to assess the biocompatibility of the fabricated SNC.