The ability to transform medical polymers, commonly used for resorbable surgical sutures, into desired 3D forms/shapes/structures at nano and micro scales with “smart” functions, while sustaining the materials’ excellent biocompatibility and biodegradability, provides significant applications in different biomedical fields, ranging from tissue engineering and controlled drug/vaccine delivery to medical devices. Here, I will present our recent research works to create 3D microstructures of biodegradable polymers for developing single-administered vaccines, and convert the biopolymers into “smart” piezoelectric nanomaterials, which can generate electricity under deformation and vice versa, offering a variety of exciting applications in biodegradable force sensors, tissue-engineering scaffolds and medical transducers.