Thin Film Acoustic Wave Platform for Conformable and Mechanically Flexible Biosensors

In this project, we will research a new platform technology to manufacture flexible devices enabling non-invasive and rapid medical diagnostics. Due to global ageing and the increased burden of cancer/chronic diseases, there is a huge demand worldwide for efficient and inexpensive mobile healthcare, e-care, and home/point-of-care systems. These will not only be able to stop the cycle of transmission in infectious diseases, thus reducing their impact, but also allow us to monitor health conditions frequently (e.g. with wearable sensors) and tailor treatment as required, thus providing more efficient therapies. A key challenge for such devices is to integrate all the functions required to perform advanced diagnostics, such as sample manipulation, purification and sensing, onto a low-cost, mechanically flexible diagnostic/treatment platform, such that testing can be performed rapidly and frequently (for example in wearable patch applications). To be widely and effectively adopted, flexible diagnostics need to be conformable to diagnostic/treatment surfaces or to adapt to changes in surface shape (such as the human body), as well as to be compatible with large scale and low cost manufacturing technologies such as roll-to-roll/printing, whilst providing versatile integrated sampling/purification/sensing functions. These flexible and body comfortable sensors are becoming a promising route for new generations of personalised biomedical tools.

Here, we will use the mechanical energy propagated by acoustic waves on the surface of flexible foils, onto which we deposited a structured piezo-electric thin film. By controlling the orientation of the film, we will be able, for the first time, to integrate a large variety of fluid manipulation functions together with highly sensitive sensing, using a single technology. This will enable us to simplify design and manufacturing constraints significantly, leading to the potential of using large scale and low-cost manufacturing, drastically enhancing the availability and usefulness of personalised diagnostic devices. Our platform is based on versatile acoustic wave modes (integrating both microfluidics and sensing) compatible with roll-to-roll manufacturing and thin film/microfabrication technologies.

In the past decades, a large number of microfluidic and molecular sensing technologies have been developed based on integrated lab-on-chip, however only a few have been successfully introduced into the market, with one key reason for this attrition being that sampling (sample selection, collection and preparation, e.g., mixing, purification, filtering, washing, and then delivering to sensors) has not been successfully integrated into complete diagnosis systems in a simple, low-cost and efficient manner. In particular, there have been significant challenges in the integration of microfluidics (for sampling) with biosensing (detection) technologies, due to the different technologies that each function relies on, rendering the instrumentation too complex for truly portable and conformable systems. In this research, in partnership with industry, we will develop an innovative solution to integrate different acoustic modalities, which can provide different actuations of the sample (sampling, purification, sensing), using the formation of inclined angled ZnO thin films, such that we are able to generate and control different wave modes, i.e., longitudinal and shear waves on one platform. This will realise low-cost/flexible acoustic wave devices with integrated sensing and microfluidic functions.

The ultimate benefit to society from the outcomes of this project will come through the provision of efficient and inexpensive mobile healthcare, e-care, and home/point-of-care systems, using an integrated and flexible acoustic wave platform. This platform will create impact through improvement in diagnosis and treatment of disease by solving the commonly-faced limitations linked with the complexity of automation of bio-sampling (from blood, saliva or other biological fluids) and highly sensitive sensing. This is critical for both the developed world (in primary care, point of care or in home diagnostics) and the developing world (with limited infrastructures or resources).

In the context of global ageing and an increasing burden of cancer/chronic diseases, these technologies will enable early diagnosis, with the potential to link to better outcomes, along with more frequent monitoring, leading to more efficient treatment regimes and better standard of living. By creating a mechanically flexible acoustic wave microfluidic platform for medical diagnostics with a non-invasive, low cost, mass production and roll-to-roll capability, we aim to impact on research, both academically and industrially, as well as more widely on the healthcare industry (with the provision of disposable diagnostic devices) and on society, providing better healthcare through enhanced disease diagnostics.

This research programme will provide technologies enabling decentralised medical diagnostics. The project demonstrator is focused on specific detection of inflammation markers, however, the integration of inclined thin film SAW technology onto flexible platform provides access to an extremely sensitive generic sensor technology with very broad applications. An important impact of the proposed research will be on relevant manufacturing sectors in the UK, including thin film based technology and microfabrication, and healthcare device manufacturing. The flexible medical diagnosis and healthcare sectors in UK and worldwide are rapidly growing, but presently still in their infancy, thus it is timely for researchers to establish a leading role. The impact of having a partnership with industry in this project will be to directly translate product concepts to product production, reducing the timescales of the inevitable iterative steps required in the development of any new process or technology. OJ-Bio is interested in extending their wireless sensing capability into flexible devices, and applying new types of enzymes and molecules to expand their application focus. Through its links to the market, Epigem will help the team accelerate the developments towards manufacturability, in particular with roll-to-roll and printing techniques.

The proposed work will also lead to the development of highly skilled multidisciplinary researchers (PDRAs) who can successfully deploy mobile health and point-of-care knowledge/techniques and facilitate its integration with both existing and new technologies and material systems. There is a great demand for these skills in the UK as well as throughout the world, with such individuals being particularly sought after in the growing health care and lab-on-chip manufacturing sectors where the majority of existing companies are SMEs.

The outputs from this project will be made available to the wider research community in the fields of biomedical diagnosis, lab-on-chip, microfluidics, thin film process, acoustic wave technology, microsystems manufacturing, through workshops, conference presentations and published papers. The successful dissemination and external implementation of the project outcomes will in turn drive forward the profile and relevance of manufacturing technologies, advanced materials, microsystems, sensors, biology, which are the key supported areas within EPSRC's remit.