Wearable technologies for sweat rate and conductivity sensors: design and principles

Wearable sensors present a new frontier in the development of monitoring techniques. They are of great importance in sectors such as sports and healthcare, as they permit the continuous monitoring of physiological and biological elements, such as ECG and human sweat. Until recently, this could only be carried out in specialized laboratories in the presence of cumbersome, and usually, expensive devices. Sweat monitoring sensors integrated onto textile substrates are not only part of a new field of work but, they also represent the first attempt to implement such an innovative idea on a system which will be worn directly on the body. The objective of this book is to present possible designs and technologies of low cost wearable sweat rate and conductivity sensors integrated onto a textile. The first chapter deals with a preliminary introduction on sweat production and composition, and the applications of wearable devices. Further, the second chapter describes the conductivity sensor, i.e. the geometry, materials and the coupling which includes a temperature sensor for precise measurements are discussed. This is followed by a chapter on the sweat rate sensor, and the technologies employed to fabricate it. Sensors that are based on a) conductive yarns coated with hydrophilic polymers, b) conductive polymer fibres, c) hydrophilic polymers between conductive fabrics and d) humidity sensors are described in detail. Finally, the last chapter provides a study of sweat production in different body areas, the calibration procedure, and summarizes the results which arise from the tests on volunteers.

Biography Pietro Salvo received the M.Sc. degree in Electronic Engineering in 2004, specialization in biomedical applications, with the thesis "Realization of low-power analogue SC-CMOS filter which implements the wavelet algorithm to analyse ECG signals in pacemakers." During his M.Sc. thesis, he was at the Delft University of Technology, Electronics Research Laboratory, Faculty of Electrical Engineering, Mathematics and Computer Science, Mekelweg 4, Delft (The Netherlands). He received the Ph.D. degree in "Automation, Robotics and Bioengineering" from University of Pisa, Italy, in 2009 with the thesis "Development of wearable sensors for the measurement of sweat conductivity and rate." From 2008 until 2009, he was at the Institute for the Conservation and Promotion of Cultural Heritage, National Council of Research, Florence (Italy) where he was involved in the development of models and protocols for the monitoring of monumental buildings and paintings. In 2009-2013, he was at the Centre for Microsystems Technology (CMST), Ghent University, Ghent (Belgium), where he was responsible of the development of sensors, electronic devices and microfluidic systems for bioengineering platforms. From 2013 to 2016, he was at the Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa (Italy) where he worked on sensors and biosensors for the monitoring of human fluids and physiological parameters. From September 2016, he is at the Institute of Clinical Physiology, National Council of Research, Pisa (Italy), where he is currently working on bioengineering applications such as a human breath sampling system, sensors for monitoring food quality and wearable sensors for wound monitoring. His scientific areas of interest include sensors and biosensors, non-invasive or minimal invasive monitoring tools, wireless sensors networks, smart materials and nanomaterials, hybrid systems, data analysis and signal processing.