Environmental friendly piezoelectric materials for sensors, actuators and implants in medical technology

Medical technology is very important for the future of healthcare and this technology depends on various components such as sensors, actuators and implants to be used inside the body such as blood pressure gauges and pacemakers. It is also important that these components are autonomous, i.e. they are self-powered and do not need to be removed from the body by surgery and replaced with new ones to change the battery. Piezoelectric ceramic materials are important for these components, but many of today's components use non-sustainable lead-containing materials. A piezoelectric material will generate an electrical charge on the surface when it is subjected to a mechanical load. The materials can generate electric current from vibrations and movements like a beating heart. The use of toxic lead-based materials is challenging in relation to using the materials in the body and for the life cycle of the components, i.e. from manufacture to recycling. In this project we have established a platform for the development of environmentally friendly and biocompatible piezoelectric materials for medical technology. We therefore contribute to meet the challenges for future improved health care and new medical technology in addition to reducing the environmental impact of the lead-containing materials contributing to the UN?s sustainable goals. The materials we have developed are biocompatible and they should have high stability in biological systems while maintaining a high functional performance. The materials are based on barium titanate and alkali niobate, materials that are expected not expelled by our body. One of the challenges with the use of the materials inside the body is that they might be in contact with body fluid. We have therefore compositionally engineered these materials to make them more robust in the in vivo environment and increase the piezoelectric performance. In the medical components, the piezoelectric materials are largely used as thin films on a substrate, and one of the main objectives of the project is the development of technology to make such thin films. We use a simple chemical deposition method that is based on an aqueous solution or a physical deposition method using sputtering from a target. We have developed several methods for making lead-free piezoelectric films with excellent functional properties. This technology has been further developed to deposit films on flexible substrates as polymers by transferring the film from a solid substrate to a flexible one. This research represents the latest developments internationally in this field and is an important step to implement the films in medical components. In collaboration with University of Sydney, we have further pioneered the investigation of the biocompatibility of these alkaliniobate piezoelectric films by studies of how different cells proliferate in contact with them. These results are very promising showing high biocompatibility of the developed films.

Prosjektet Environmental friendly piezoelectic materials for sensors, actuators and implants in medical technology har utviklet nye materialer som kan benyttes i medisinsk teknologi og disse materialenes biokompatibilitet. Prosjektet har bidratt til å etablere biokeramer som et fagområde i faggruppen FACET Funksjonelle materialer og materialkjemi, Institutt for materialteknologi. Dette er et svært viktig område som vil bli ytterligere forsterket i framtida. Prosjektet har også styrket den tverrfaglige aktiviteten på instituttet gjennom et internasjonalt forskningssamarbeid med det medisinske fakultet, University i Sydney. Dette er et svært viktig samarbeide da de har komplementær kompetanse til oss og består med evalueringen av biokompatibiliteten til materialene. Prosjektet har også bidratt til et mye større fokus på ansvarlig forskning i FACET forskningsgruppen og dette har blitt implementert som en naturlig del av vår virksomhet.

Medical technology is rapidly developing to improve diagnosis and medical treatment tools and providing important health benefits. Advances in medical technology rely on further development of sensors, actuators and implants to be used also in vivo. Current devices utilizing piezoelectric/ferroelectric materials are based on non-sustainable lead-containing materials. The use of toxic lead-based materials is challenging both with respect to in vivo application of the materials and to the life-cycle of devices. In this project including strong international collaboration we will conduct research with the aim to establish a platform for synthesis of environmentally friendly and biocompatible high-performance piezoelectric materials for medical technology. The project will thus contribute to meet future challenges with improved health care and new medical technology as well as reduced environmental concerns. The project consists of five mutually dependent work packages which include compositional engineering of the KNN- and BZCT-based materials to achieve biocompatible materials with high durability in biological conditions while still maintaining high piezoelectric performance. Further chemical solution deposition routes to thin films of the biocompatible and durable piezoelectric materials will be developed and in order to exploit the results of the compositional engineering on an industrially relevant platform for MEMS, protocols to deposit thin films by CSD onto silicon substrates using buffer layers will be developed. A comprehensive materials characterization program is established and special focus will be given to study the biocompatibility of the new materials. The project will be dependent on extended use of the national research infrastructures such as RECX, NORTEM and NORFAB. The project will educate one PhD candidate and one post doc and 5-10 publications in international peer review journals will be published.