Control of piezoelectricity in amino acids by supramolecular packing

Abstract

Piezoelectricity, the linear relationship between stress and induced electrical charge, has attracted recent interest due to its manifestation in biological molecules such as synthetic polypeptides or amino acid crystals, including gamma (γ) glycine. It has also been demonstrated in bone, collagen, elastin and the synthetic bone mineral hydroxyapatite. Piezoelectric coefficients exhibited by these biological materials are generally low, typically in the range of 0.1-10 pm V, limiting technological applications. Guided by quantum mechanical calculations we have measured a high shear piezoelectricity (178 pm V) in the amino acid crystal beta (β) glycine, which is of similar magnitude to barium titanate or lead zirconate titanate. Our calculations show that the high piezoelectric coefficients originate from an efficient packing of the molecules along certain crystallographic planes and directions. The highest predicted piezoelectric voltage constant for β-glycine crystals is 8 V mN, which is an order of magnitude larger than the voltage generated by any currently used ceramic or polymer.

Biomolecular Piezoelectric Materials: From Amino Acids to Living Tissues

“…The crystal class of α‐glycine is a central symmetry point group, which excludes piezoelectricity. On the other hand, the crystal classes of β‐glycine and γ‐glycine must exhibit piezoelectric reaction, because they have a noncentral symmetry point group ( Figure ) 68–72. Initial studies of glycine reported very low piezoelectric coefficients, and its origin remained unclear.…”

Nature Driven Bio‐Piezoelectric/Triboelectric Nanogenerator as Next‐Generation Green Energy Harvester for Smart and Pollution Free Society

“…Thus, this strong interaction among them (crystalline domains structure and the strained elastic semi-amorphous regions) could be one of the possible reasons behind the development of out of plane/ vertical piezoelectricity as well as outstanding piezoelectric behavior in the nature driven silk fibrils. [106] High shear piezoelectricity value of ≈178 pm V −1 was reported in amino acid crystal β glycine, through quantum mechanical calculations. [100,101] Karan et al described that water immersion/spraying on the nature driven SS fibrils followed by wrapping improves its crystallinity, by increasing the percentage of β-sheet content which strongly facilitates the well orientation of the microfibrils inside the lattice crystal structure of silk fiber.…”

“…Due to internal polar atomic groups rotation surrounding the asymmetric carbon atom inside crystalline biomaterials, may be reason to generate piezoelectric effect in nature driven biomaterials. [106] Copyright 2018, Springer Nature Publishers. In their opinion, plant materials would be very much effective in terms of their availability and handle compared to living creature.…”

Functional metabolite assemblies—a review

“…Guerin et al (2018) have recently demonstrated high piezoelectricity values in certain polymorphs of glycine crystals by efficient packing of the molecules along specific crystallographic planes and directions. Piezoelectricity is the linear relationship between stress and induced electrical charge.…”

“…c Manual compression of a γ-glycine seed crystal layer. Full compression of the layer as shown averaged a force of 0.172 N (adapted from Guerin et al 2018 with permission)…”