Microprinting of bioresorbable piezoelectric racemic amino acid films with aligned grains for power generation and implantable devices

In this study, we introduce a novel microprinting technique using the electrohydrodynamic spray method to fabricate piezoelectric racemic amino acid films. By applying an in-situ electric field, we achieved controlled manipulation of DL-alanine biomolecules, resulting in films with a uniform and dense nanocrystal distribution. The DL-alanine films exhibit a high effective piezoelectric constant of approximately 12.3 pm V-1, three times higher than those prepared by solution casting. We also successfully demonstrated their applications in sensors and power generation, where the piezoelectric devices produce an impressive open-circuit output voltage of about 10 V, ten times higher than the previously reported value. The asfabricated DL-alanine films are naturally flexible, biocompatible, biosafe, and bioresorbable, making them promising for transient bioelectronics and implantable microdevices.