Coordination-Driven Assembly Modulates the Piezoelectric Response of Bio-Inspired Amino Acid-Based Supramolecular Materials

Metal ion coordination confers unique supramolecular structures and electronic properties to biomolecular assemblies in living organisms, inspiring the design of metallo-supramolecular piezoelectric biomaterials. However, the piezoelectric response of biomolecule-based metallo-supramolecular materials and structure-piezoelectricity relationships are still largely unexplored. Herein, we present a bio-inspired metal coordination strategy to modulate the piezoelectricity of copper(II) amino acid assemblies toward energy harvesting. Interestingly, crystal structures indicated dimensionally diversified coordination networks in copper(II) amino acid assemblies, including zero-dimensional (0D) discrete blocks, one-dimensional (1D) infinite chains, and two-dimensional (2D) infinite sheets. Notably, density functional theory (DFT) calculations revealed that the dimensionality of coordination networks fundamentally modulates the maximum piezoelectric strain coefficient of assemblies with the order: 1D > 2D > 0D, in which the copper(II) l-glutamate (Glu+Cu) coordination assemblies exhibited the highest value of 57.7 pC/N. The Glu+Cu crystal-based piezoelectric device produced stable open-circuit voltages exceeding 3.0 V under 55 N mechanical force, which could be fabricated into real-time monitoring systems for cervical and lumbar spine health. This work presents a novel metal biocoordination strategy to manipulate the piezoelectric response of amino acid-based assemblies, providing essential design clues for developing innovative piezoelectric biomaterials.