Molecular engineering of piezoelectricity in collagen-mimicking peptide assemblies

Realization of a self-assembled, nontoxic and eco-friendly piezoelectric device with high performance, sensitivity and reliability is desirable to complement inorganic and polymer materials. Hierarchically organized natural materials such as collagen exhibit electromechanical properties that could be amplified via molecular engineering. Here, using a minimal collagen building block, we fabricate peptide-based piezoelectric generators utilizing a helical arrangement of Phe-Phe-derived tripeptides Pro-Phe-Phe and Hyp-Phe-Phe, composed only of proteinogenic amino acids. Addition of a hydroxyl group increases the predicted piezoelectric response by an order of magnitude (d35 = 27 pm V−1), the highest predicted to date in short natural peptides. We demonstrate tripeptide-based power generators producing stable maximum current >50 nA and potential >1.2 V. These results provide a device demonstration of computationally guided molecular engineering of piezoelectricity in peptide nanotechnology.