Ferroelectricity and piezoelectricity in soft biological tissue: Porcine aortic walls revisited

Abstract

Recently reported piezoresponse force microscopy (PFM) measurements have proposed that porcine aortic walls are ferroelectric. This finding may have great implications for understanding biophysical properties of cardiovascular diseases such as arteriosclerosis. However, the complex anatomical structure of the aortic wall with different extracellular matrices appears unlikely to be ferroelectric. The reason is that a prerequisite for ferroelectricity, which is the spontaneous switching of the polarization, is a polar crystal structure of the material. Although the PFM measurements were performed locally, the phase-voltage hysteresis loops could be reproduced at different positions on the tissue, suggesting that the whole aorta is ferroelectric. To corroborate this hypothesis, we analyzed entire pieces of porcine aorta globally, both with electrical and electromechanical measurements. We show that there is no hysteresis in the electric displacement as well as in the longitudinal strain as a function of applied electric field and that the strain depends on the electric field squared. By using the experimentally determined quasi-static permittivity and Young's modulus of the fixated aorta, we show that the strain can quantitatively be explained by Maxwell stress and electrostriction, meaning that the aortic wall is neither piezoelectric nor ferroelectric, but behaves as a regular dielectric material.

Waste Autochthonous Tuscan Olive Leaves (Olea europaea var. Olivastra seggianese) as Antioxidant Source for Biomedicine

“…P(VDF-TrFE) was specifically chosen for scaffold fabrication for its chemical inertia and non-degradability, in order to prevent any biomaterial damage following hydrogen peroxide administration. P(VDF-TrFE) possesses additional peculiar characteristics, such as piezoelectricity, which can be exploited to obtain truly functional 3D models of blood vessels [30,31,32]. It has been outlined that tissue-engineered in vitro models are more reliable than conventional 2D cell cultures on tissue culture plastics [15].…”

Electrically Polarized Hydroxyapatite: Influence of the Polarization Process on the Microstructure and Properties

“…This mainly affects the regulation of the OH – groups contained in the form of columns along the c -axis of the lattice. Generation of vacancies, re-alignment of the OH – groups, and doping of the HAp by OH – substitution are the origin of new interesting properties like proton conductivity, − ferroelectric-like properties, − and catalytic activity. , Regarding the latter application, we recently used permanently polarized HAp as an electrophotocatalyst for the synthesis of amino acids through the fixation of N 2 , CO 2 , and CH 4 …”

Negative piezoelectric effect in an organic supramolecular ferroelectric

“…aortic walls, have negative electrostriction coefficients yet are likely not piezoelectric. 27 The key to the negative longitudinal piezoelectricity in these materials is the coexistence of two phases of different elastic compliance, with a condition that the stiffer of the two is ferroelectric with the polarization in the thickness direction while the softer is anisotropically deformable (with Poisson ratio n o 0.5). This leads to coupling between the dipole density and the macroscopic dimensions of the sample and has been shown to underly direct as well as converse piezoelectric response (see Dimensional effect in the ESI †).…”