Nanyang Technological University, Daniel Chan team: not sweat the impact of high adhesion can stretch the skin electrode

Skin electrodes can be bonded to the surface of the skin, prolonged monitoring electrophysiological signal of the human body, such as ECG, EMG, EEG signals and other signs, it has potential applications in the field of remote health monitoring healthcare, disease, early diagnosis and management of human emotions . Existing commercial skin electrodes mainly composed of silver / silver chloride electrode and the conductive polymer poly methyl propionate gel adhesive layer, are widely used in a static electrical physiological signal acquisition, time can not be applied to dynamic human electrophysiological signal monitoring. This is because these electrodes business, there are some important issues in such applications: commercial electrodes can not follow skin deformation and stretching, leading to electrodes in the dynamic process of the body – skin contact interface instability; moreover, in the long monitoring, skin difficult to avoid sweating, the sweat and the adhesive layer will decrease the adhesion of the surface energy of the skin, resulting in the electrodes move freely even fall off the skin surface. These issues will affect the stability and reliability of the dynamic human physiological monitoring electrical signal for a long time, especially with a clinical diagnosis based on the early diagnosis of heart disease for a long time Holter monitoring.


In order to solve the above problems, Nanyang Technological University professor Daniel Chan and Professor Yew-SoonOng in \”ACS Materials Letters\” published entitled \”Adhesive Bio-compositeElectrodes on Sweaty Skin for Long-term Continuous ElectrophysiologicalMonitoring\” of research papers, co-first author Bo Kyi less Tianjin University professor Yang Hui and Nanyang Technological University of Singapore. Researchers biological composite electrode (CAPE) having a high adhesion to the sweat skin surface successfully prepared by in situ interfacial polymerization, and applied for a long time dynamic electrophysiological monitoring. Design is based on the moisture of the article in response to a biological silk fibroin composite electrode in the presence of perspiration can maintain high adhesion energy. Silk fibroin adhesive layer with the water content increases, the Young\’s modulus is lowered to close the skin in order to achieve a silk fibroin conformal adhesion layer and the skin (conformal adhesion), to enhance the adhesion of the interface between the composite electrode and the skin performance. Polypyrrole as a conductive polymer, having a low resistance, good biocompatibility, and low cost, but not limit its stretchedApplication of flexible stretchable electrodes. Researchers in advance Jiaru Si layer fibroin Fe (III) ion as an initiator, initiator in the ionomer pyrrole silk fibroin gel surface interfacial polymerization to obtain a bio-stretchable composite electrode. Fibroin adhesive layer between the conductive polypyrrole layer formed by interfacial polymerization close interlocking structures, so that the interface includes a three-dimensional network structure interpenetrating, this structure will be good silk fibroin gel layer transfer tensile properties polypyrrole to make it malleable and to achieve the mechanical properties compatible with each other, to ensure uniform stretching of the electrodes and maintain good electrical stability at 30% strain typical skin deformation.

a) bio-composite electrode (CAPE) Raman spectrum showing a sectional structure of interlocking interpenetrating interface. b) bio-composite electrodes exhibit excellent tensile properties, electrochemical polypyrrole attached directly to the resulting silk fibroin membrane layer (no interlocking features) poor stretchability.

High adhesion of biological composite electrode, stretchability, and good conductivity, it is possible to stably record electrophysiological signals dynamically under sweating in the body movement, and higher sensitivity commercial gel electrodes, can be used for long-term human dynamic electrophysiological signal monitoring. Further, the flexible electrode stretchable composite electrodes with the skin when the skin deformation perfect fit, the skin exhibits highly conformal and conformal contact, when large skin deformation elbow motion can stably adhere body epidermis.

Biological conformal composite electrode may adhere to the skin and subjected to strain at the elbow motion. Shows an enlarged view of the surface of the skin occurred after the same biological composite electrode lines conformal adhesion.

Researchers also show us the composite electrode and human body physiological signal monitoring applications: as applied to the measurement of ECG, it can be used for early diagnosis of underlying coronary artery disease; for sport management, monitoring heart rate during exercise change, providing scientific movement to arrange a healthy lifestyle reference; ECG signal is analyzed for sentiment monitoring through machine learning; or the composite electrodes used in EEG records used to assess sleep status.

a) using a commercially available electrode (a) and bio-composite electrode (lower) ECG during running. With the accumulation of sweat during exercise, the commercial electrode contact with the skinTouch unstable and fall gradually; biological composite electrode good adhesion and gathering stable ECG signal. b) the use of classified ECG signal for machine learning. c) Real-time ECG recording composite electrode through biological object sentiments determination and monitoring.


Researchers designed by interfacial polymerization skin flexible electrode current development of a flexible stretchable electrode based on total polymer polypyrrole and silk fibroin overcome the preparation of adhesion performance degradation when sweating skin, the epidermis easily detached from defects, and in the surface of the skin sweating a high adhesion performance, achieving a long-term dynamic human physiological signal monitoring during exercise can be used in sports management, monitoring mood, disease diagnostic and other fields. References: Hui Yang #, ShaoboJi #, Iti Chaturvedi, Huarong Xia, Ting Wang, Geng Chen, Liang Pan, Changjin Wan, Dianpeng Qi, Yew-Soon Ong *, and Xiaodong Chen * Adhesive Bio-composite Electrodeson Sweaty Skin for Long .. -term Continuous electrophysiological Monitoring ACSMaterials Letters, 2020, 2, 478-484 full text link: https: //