Biointerfaced Nanopiezoelectrics

Abstract

Biointerfaced nanopiezoelectrics refers to the generation, fundamental study, and device applications of piezoelectric nanomaterials and their interfaces with cells and tissues. This field has the potential to impact areas ranging from new nanomaterial properties, to better understanding of electromechanical effects in biological systems, and finally to applications in bio-mechanoelectric sensing, energy harvesting and regeneration. Piezoelectric materials are smart materials which can convert between mechanical and electrical energy. Lead Zirconate Titanate (PZT) is among the most efficient piezoelectrics for this transduction, with a piezoelectric charge coefficient of ~ 250 pC/N in bulk. Accordingly, PZT nanomaterials could represent promising platforms for applications at small scales such as nanogenerators, nanosensors and nanoactuators. However, PZT nanomaterials are challenging to synthesize due to the stringent material stoichiometry for maximal conversion efficiency. Here, we show that high performance PZT nanomaterials can be fabricated over large areas, and exhibit large piezoelectric coefficients. We can transfer these nanopiezoelectrics onto flexible, stretchable, and biocompatible elastomeric substrates while retaining their performance. Most significantly, we show that the PZT nanomaterials can be used to interface with cells and tissues for applications in sensing mechanical signals that are inherent to cellular physiology. PZT nanomaterials enable size-commensurate interfaces with tiny cellular structures which are able to detect minute mechanical effects in cells. Finally, we show that the scalability of the PZT nanoribbons enables the creation of arrays which can be biointerfaced with lung tissue to measure deformations in a mimicked respiratory process. For future directions, PZT nanomaterials could function as actuators to mechanically stimulate and engineer nerve regeneration. As application first step, we demonstrate the capability of mechanical forces to induce rapid growth of neurites in a microfluidic device. Thus, research on the field of biointerfaced nanopiezoelectrics could have a substantial impact on many areas, ranging from the fundamental study of new nanomaterial properties and mechanical effects in cells to various applications such as electromechanical prosthetics, human-machine interfaces, and regenerative biomedicine.