Manipulating the Piezoelectric Response of Amino Acid-Based Assemblies by Supramolecular Engineering

Variation in the molecular architecture significantlyaffects theelectronic and supramolecular structure of biomolecular assemblies,leading to dramatically altered piezoelectric response. However, relationshipbetween molecular building block chemistry, crystal packing and quantitativeelectromechanical response is still not fully understood. Herein,we systematically explored the possibility to amplify the piezoelectricityof amino acid-based assemblies by supramolecular engineering. We showthat a simple change of side-chain in acetylated amino acids leadsto increased polarization of the supramolecular arrangements, resultingin significant enhancement of their piezoelectric response. Moreover,compared to most of the natural amino acid assemblies, chemical modificationof acetylation increased the maximum piezoelectric tensors. The predictedmaximal piezoelectric strain tensor and voltage constant of acetylatedtryptophan (L-AcW) assemblies reach 47 pm V-1 and1719 mV m/N, respectively, comparable to commonly used inorganic materialssuch as bismuth triborate crystals. We further fabricated an L-AcWcrystal-based piezoelectric power nanogenerator that produces a highand stable open-circuit voltage of over 1.4 V under mechanical pressure.For the first time, the illumination of a light-emitting diode (LED)is demonstrated by the power output of an amino acid-based piezoelectricnanogenerator. This work presents the supramolecular engineering towardthe systematic modulation of piezoelectric response in amino acid-basedassemblies, facilitating the development of high-performance functionalbiomaterials from simple, readily available, and easily tailored buildingblocks.

Automated summary

This study systematically explored the supramolecular engineering of amino acid-based assemblies and found that chemical modification of acetylated amino acids can enhance their piezoelectric response. By fabricating an L-AcW crystal-based piezoelectric power nanogenerator, the illumination of a light-emitting diode (LED) was successfully demonstrated using the power output of an amino acid-based piezoelectric nanogenerator.