MultiSense - Devising and Manufacturing mm-Wave High Data Rate Low Latency On-Skin Technologies

Lead Research Organisation: University of Kent
Department Name: Sch of Engineering & Digital Arts

Abstract

This multidisciplinary project will exploit an established UK based team's track record comprising RF & bio-sensing engineers, battery & materials scientists, and CPI, the UK National Catapult for Printed Electronics. Centred around Additive Manufacture and aimed towards scale-up, we will transform nascent wireless skin-based sensing to the high data rate capacity offered by upcoming communications systems using license-free 24 GHz channels. This will enable new streaming of biodata for remote diagnostics, monitoring and care, as well as ultra-low impact wireless EEG for forehead/ear/hair free regions. It will make possible the use of multiple sensing tags on multiple people simultaneously monitoring physiological parameters such as accelerometery (for activity tracking), photoplesmography (for heart rate monitoring), and sweat (for metabolite monitoring). At high data rate, this represents a step change over available technologies.

Manufactured on highly flexible, potentially stretchable, substrates the skin tags take the form factor of temporary tattoos and are highly long lasting, discrete for social acceptability, and can follow the micro-contours of the skin to give a large contact surface area and consequently sensing signal-to-noise ratio. To achieve our aims, we will advance wireless mmWave devices, on-skin electronics, low-power bio-sensing, and additive manufacture. Additionally, through CPI, we will develop scale-up processes for these mmWave devices.

Through existing investments the applicant team is positioning the UK for the large scale manufacture of on-skin sensor tags. EP/P027075/1 is creating an inkjet printing based manufacturing process for sensors on flexible substrates which avoids cleanrooms, uses graphene based ink formulations for biodegradability, and can be scaled up large run roll-to-roll screen printing. EP/R02331X/1 added the capability to print TiO2/LiFePO4 batteries integrated into the platform, removing a key integration bottleneck. This new proposal 'MultiSense' seeks to build upon the manufacturing base created by these two projects, extending it to overcome the key sensing limitation of current on skin tags: that they can only monitor one parameter from one person at a time, and at a comparatively low data rate. These projects are further limited to producing first principle non-elastic, low capacity integrated batteries and UHF frequency (868 MHz) RF devices which require print resolutions similar to conventional masks for wet etching (typically 200 um). Further, our experience of UHF RFID reveals transmission delays of 6 ms, and a reliable data rate upper limit of only 400 bps (corresponding to a sample rate of just 30 Hz for a modality such as accelerometry).

In MultiSense, we propose to overcome these limitations by moving from RFID to 24 GHz ISM (Industrial, Scientific Medical) band transmission, where very substantial uncongested bandwidth is available, offering orders of magnitude higher bit rates than UHF. In addition, the smaller wavelengths will increase antenna miniaturisation on integrated elastic substrate batteries, requiring print resolutions of 50 um. The new batteries will be solid state and polymer based with elastic current collectors. We will also investigate the mmWave signal surface guiding over the skin as a mechanism to allow for inter-patch communications. Sensing robustness will be improved as minor variations/misplacements in the sensor positions could be captured, and potentially corrected for in software. This will impact on diagnostic EEG measurements where currently entire datasets (from cabled electrodes) might be abandoned when individual electrodes disconnect. To enable the measurement of skin-based transmission between patches with new dry electrode designs, we will work with International Research Visitor Professor Koichi Ito of Chiba university, an expert in human phantom design.

Planned Impact

Economy
To reach the wider population through translation and commercialisation it is highly likely that patentable IP will be produced. (In the areas of printed batteries, printable graphene ink formulations, and multi-modal sensing, amongst others.) An IP agreement will be made between the UK investigators. All the proposers have patents (applied for or granted) and we will work with UMIP and KIE (University of Manchester Intellectual Property and Kent Innovation and Enterprise), together with CPI, all of whom have a strong track record in bringing innovative products to market. We appreciate that suites of related IP are more attractive as a commercial proposition than individual patents, and this will be reflected in our strategy which may involve licensing IP if most appropriate. CPI has a strong track record with UK and EU industry with over 150 collaborations with UK companies in this field, and an extensive cluster of local electronic companies (e.g Neudive). Additionally, Manchester runs 100 industry focused events each year, these are of different scales and involve trade associations and KTNs. We will continue our discussions through these events to maximise the relevance and exposure of our project outputs and showcase our system demonstrator at tradeshows and professional events to connect with industry including PragmatIC and PEL.

Health & society
The increasing costs of healthcare and the ageing population are major challenges for the UK. The proposed work will tackle these through the creation of new non-invasive sensors for long term sensing of multiple parameters to provide preventative monitoring for a wide range of conditions. Casson is CI on EP/P010148/1, working with NICE to integrate wearable devices into care pathways, and MRC projects to give clinical context to the manufacturing research proposed here. We will incorporate a number of modalities into our sensor tag platform, with multi-channel EEG taken as a lead example as it requires a particularly high data rate, and is widely used clinically for epilepsy diagnosis, sleep disorder diagnosis, chronic pain investigations, and others. Despite this wide use, easy to apply, long lasting, and self-registering of location electrodes are an unmet clinical need (see letters of support), and the successful outcomes of this research could directly address this need.

Knowledge, people & outreach
The research will make a step change in the critical mass of UK engineering and physical sciences skills to tackle emerging challenges in manufacturing and in healthcare. It will make cross cutting advances that impact many technical areas, building knowledge in printed sensor node manufacture, body loading of antennas, & long term vital sign monitoring. In addition, while the specific research carried out will be focused on skin mounted transient conformal sensors, sensor driven interventions are emerging in a number of areas, from structural monitoring to energy management. It is thus highly likely that the technical advances arising from this work will impact these areas too, facilitating printed sensor based monitoring and feedback in several modalities and situations that are not currently possible. This will lead to wide ranging impact on scientific knowledge. A number of public engagement events, such as schools visits and attending the national 'Big Bang' fair, based on the research are also built into the programme to excite future manufacturing professionals to enter the sector. This will ensure the manufacturing skills pathway is complete: giving skill and knowledge dissemination beyond the immediate research team; inspiring future engineers and scientists; and allowing the general public to connect with research leaders. Where possible the physiological data collected will be publicly available, providing a rich resource for data mining research. Similarly, hardware & software outside our commercialization strategy will be made open access.

Publications

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