The ability to transform medical polymers, commonly used for resorbable surgical sutures, into desired 3D forms/shapes/structures at small-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-delivery to medical devices. Here, I will present my recent inventions to create 3D microstructures of biodegradable polymers for developing single-administered vaccines, and convert the biopolymers into “smart” piezoelectric materials, 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.