Flexible Proton-Conducting Biocomposites Based on Amino Acid Biomolecules

Proton-conducting biomaterials have emerged as promising candidates for bioelectronics due to their excellent biocompatibilities and tunable electronic properties. Primarily built on proteins, this group of materials suffers from high humidity-dependent conductivity, poor stability, and brittleness under dry conditions. To address these challenges, we developed a proton-conducting biocomposite film by integrating amino acids and glycerol into a poly(acrylic acid) (PAA) matrix. Introducing polar groups from amino acids, along with the enhanced water absorption and retention from glycerol, makes this biocomposite an excellent flexible proton conductor, achieving comparable proton conductivities as dried natural proteins and maintaining stability under moderate mechanical stresses. The as-prepared film was successfully applied as the active layer in a moisture electric generator (MEG), generating a stable voltage of ∼0.17 V and a short-circuit current of 0.18 μA under ambient conditions. These findings highlight the potential of PAA-amino acid-glycerol films for next-generation self-powered wearable electronics and biointegrated devices.