The Multi-channel Sweat Detection System Based On Flexible Epidermal Electronics

Wearable technology provides support for the realization of personalized medicine,most wearable devices today only measure physical or electrophysiological parameters,ignoring information at the molecular and ion levels.Flexible skin sensors have the characteristics of ultra-thin,stretchable,breathable and low energy consumption,which can be combined with human skin in a soft and tight way,solving the problem of mismatch between traditional rigid devices and biological systems,and providing an opportunity for physiological information monitoring of molecular and ion levels.The sweat contains rich physiological and metabolic information,which can achieve noninvasive collection and monitoring.Sweat monitoring mainly used in sports status,disease prediction,diagnosis,and drug analysis.At present,the collection and monitoring of sweat relies on large instruments and cannot achieve continuous and realtime monitoring.Based on the above analysis,it is important to develop self-driven collection and real-time monitoring sweat sensors using flexible electronic technology.The contents of this paper are divided into the following aspects:Firstly,this paper introduces the design principles of flexible stretchable sweat sensors and the self-driven microchannel.In order to obtain more comprehensive and abundant information,multi-channel sweat sensors were designed.Based on electrochemical principle and flexible electronic manufacturing technology,the sensor electrodes were fabricated and modified to realize the concentrations monitoring of glucose,lactate,sodium ions,potassium ions,calcium ions and chloride ions in sweat.Since sweat is easily evaporated and contaminated,the microchannel is used to collect sweat,achieving in vivo monitoring.Secondly,the fabrication methods of flexible stretchable sweat sensors and the self-driven microchannel are introduced.The fabrication of the flexible stretchable sweat sensors is divided into the fabrication and modification of electrodes.Next,this article introduces sweat sensors interface circuits,Bluetooth transmission circuits and the display APP.Since the biosensor signals have the characteristics of small signals,high noise and low frequency,it is necessary to design amplification and filtering circuits.Considering the mismatch between flexible sensors and the rigid circuits,the cylindrical conductive magnetic particles were used for connection.The connection methods of the magnetic particles with sensors and circuits were explored.Finally,the feasibility of the sweat system was tested by in vitro and in vivo experiments to test the sensitivity and anti-interference characteristics of the sweat sensors.Based on the above content,this paper proposes a multi-channel,flexible and stretchable epidermal sensor system for sweat monitoring,which realizes self-driven sweat collection microchannel,electrochemical sensor analysis,magnetic absorption interface,signal processing and Bluetooth transmission,APP display and other functions.