Biodegradable Self-Folding Polymer Films with Controlled Thermo-Triggered Folding

Self-folding films are a unique kind of thin film. They are able to deform in response to a change in environmental conditions or internal stress and form complex 3D structures. They are very promising candidates for the design of bioscaffolds, which resemble different kinds of biological tissues. In this paper, a very simple and cheap approach for the fabrication of fully biodegradable and biocompatible self-rolled tubes is reported. The tubes' folding can be triggered by temperature. A bilayer approach is used, where one component is active and another one is passive. The passive one can be any biocompatible, biodegradable, hydrophobic polymer. Gelatin is used as an active component: it allows the design of (i) self-folding polymer films, which fold at room temperature (22 degrees C) and irreversibly unfold at 37 degrees C, and (ii) films, which are unfolded at room temperature (22 degrees C), but irreversibly fold at 37 degrees C. The possibilities of encapsulation of neural stem cells are also demonstrated using self-folded tubes.