 The study presents an amino acid-based piezoelectric biocrystal thin film with tissue-compatible omnidirectional stretchability and unimpaired piezoelectricity, achieved through a truss-like microstructure self-assembled under-controlled molecule-solvent interaction and interface tension. The large-scale biocrystal microstructure can endure up to 40 percent tensile strain along different directions while retain both structural integrity and piezoelectric performance. A tissue-compatible stretchable piezoelectric nanogenerator was developed based on this structure which could conform to various tissue surfaces and exhibit stable functions under multidimensional large strains. The study integrates piezoelectricity, stretchability and biocompatibility in one material system, a critical step toward tissue-compatible biomedical devices. This article was authored by John Lee, Koi Carlos, Houjou, and others.