Piezoelectricity and Ferroelectricity in Biomaterials: From Proteins to Self-assembled Peptide Nanotubes

Piezoelectricity is one of the common ferroelectric material properties, along with pyroelectricity, etc. There has been widespread observation of piezoelectric and ferroelectric phenomena in many biological systems and molecules, and these are referred to as biopiezoelectricity and bioferroelectricity. Investigations have been made of these properties in biological and organic macromolecular systems on the nanoscale, by techniques such as atomic force microscopy (AFM) and piezoresponse force microscopy (PFM). This chapter presents a short overview of the main issues of piezoelectricity and ferroelectricity, and their manifestation in organic and biological objects, materials and molecular systems. As a showcase of novel biopiezomaterials, the investigation of diphenylalanine (FF) peptide nanotubes (PNTs) is described in more detail. FF PNTs present a unique class of self-assembled functional biomaterials, owing to a wide range of useful properties, including nanostructural variability, mechanical rigidity and chemical stability. The discovery of strong piezoactivity and polarization in aromatic dipeptides [ACS Nano 4, 610, 2010] opened up a new perspective for their use as nanoactuators, nanomotors and molecular machines as well possible biomedical applications.