WP 3

This project deals with preparation and nanoelectromechanical characterization of piezoelectric biomaterials at the intersection of materials science, biology, and biotechnology. Recently discovered biomaterials have the potential to replace some inorganic piezoelectrics and electronic devices and can be used as naturally biocompatible materials in medical implants where bioelectromechanical actuation or charge redistribution is required. The project is focused on the deposition of piezoelectric biomaterials, and the prediction, characterization, and interpretation of the piezoelectric properties at the micro- to nanometre scale using PFM and biomolecular modelling.

Work Package 3a: Piezoelectricity and ferroelectricity in aminoacids

ESR8-Ensieh Seyedhosseini. Host University: University of Aveiro, Aveiro, Portugal. Secondments: University College Dublin, Dublin, Ireland.

Amino acids are extremely important in biochemistry, nutrition, neurology, psychiatry, pharmacology, nephrology, gastroenterology and microbiology. One particularly important function is as the building blocks of proteins, which are chains of amino acids. Among their properties as life-coordinating molecules, the chemical and catalytic ones were the most studied up to now. There is a lot of evidence that many amino acids are noncentrosymmetric and can be even ferroelectric when probed at the nanoscale. Thus, data on their local electromechanical behaviour is crucial and requires specialized SPM methods (e.g. PFM in liquids) to measure the electromechanical activity and ferroelectricity in microcrystals. In this project, several amino acid crystals are prepared. The work is include development of a suitable deposition method (based on a wet chemical technique) allowing their controllable deposition. The nanoscale piezoelectric and ferroelectric properties are studied using PFM. Results of this work can be compared with data obtained on single proteins and macromolecular assemblies of collagen, fibrin, and elastin which contain amino acid sequences and will be very useful for the understanding of micromechanical properties and the performance of protein molecules.

Work Package 3b: Piezoelectric properties of Aromatic Peptides (layers, nanotubes, and arrays)

ESR9-Kate Ryan. Host University: University College Dublin, Dublin, Ireland. Secondments: University of Aveiro, Aveiro, Portugal.

Peptide nanostructures (PNTs) will be prepared at UAVR, Aveiro, Portugal, using several techniques. PNTs are very important for bio-MEMS and various sensors as they exhibit a pronounced piezoelectric effect. The nanoscale piezoelectric properties will then be extensively investigated at NUID-UCD, Dublin, Ireland as a function of humidity in closed imaging cells, in solution, and ultimately in physiological conditions to determine the functionality of peptide-based devices for biomedical applications. Molecular simulations will be done also at NUID-UCD in order to shed light on the nanoscale units responsible for the high electromechanical properties of peptides. This project is intrinsically related to project 1A but the self-assembly of peptides requires significant modelling efforts to understand nanoelectromechanics of this type of materials.

Work Package 3c: Piezoelectric and ferroelectric properties of DNA nucleobase crystals

ESR12-Sabine M. Neumayer. Host University: University College Dublin, Dublin, Ireland. Secondments: University of Aveiro, Aveiro, Portugal.

The primary biopolymer of scientific inquiry, as it contains all of the genetic instructions to build a living organism, is deoxyribonucleic acid (DNA). With the recent completion of mapping the human genome, and advances in nanotechnology-based applications of DNA (e.g., DNA origami, scaffolds for complex nanomachinery, etc.), there is renewed interest in nanoscale characterization techniques for imaging, sequencing, manipulating, and measuring electrical, mechanical, and electromechanical properties of DNA. In this project, crystals of DNA will be synthesized, and their local piezoelectric properties will be investigated at UAVR, Averio Portugal, and NUID-UCD, Dublin, Ireland. As with some other biopolymers, it may be possible to change the local structure of DNA via the application of dc bias. The measurements will also be performed as a function of thermal and optical excitation. The ESR will combine these local electromechanical measurements with ultrahigh resolution imaging in liquid environments available on custom built low noise AFMs at NUID-UCD, allowing the structure of the DNA to be resolved at the sub-molecular level in physiological environments. Structural changes resulting from modification of the surfaces will be studied in detail. The interaction between these potentially piezoelectric crystals and the hydration layers at the DNA-water interface will provide key insight into using the functional properties of such DNA scaffolds.