Stiff (nonintrusive) passive dry electrodes doesn’t require a buffering circuit, but need the conductive gel to fix them on the skin to reduce motion artifacts [16].In recent years, considerable attention has been given to various dry electrode designs, such as Micro-Electro-Mechanical Systems (MEMS) dry electrodes (intrusive) [7,17�C22], soft dry electrodes (nonintrusive) [23], dry electrophysiology electrodes using carbon nanotube (CNT) arrays (nonintrusive) [24], conductive textile-based electrodes (nonintrusive) [25], and flexible polymeric dry electrodes (nonintrusive) [26�C28]. To conclude, these studies explain why dry electrodes are important for bio-potential acquisition devices.The acquisition electrodes used affect the quality of the biomedical signal. Some dry electrodes are made of stiff substrates that can damage skin tissue when the electrode is removed [7,17�C22]. Recently, Gruetzmann et al. [23] propose a soft and flexible electrode to improve the motion artifacts in order to reduced contact impedance for ECG measurement. Under slight pressure, the soft and flexible dry electrode on skin that has well contact with skin than stiff electrodes. Baek et al. were the first to propose a PDMS-based flexible dry electrode [26] for ECG measurement and PDMS is a bio-compatible material [26�C29]. Kim et al. [27] and Moon et al. [28] used the same material to fabricate sensor substrates. However, connecting the wire to the PDMS electrode is challenging. Generally the conductive glue is used as the connective interface between the wire and the PDMS [26�C28], which provides a weak interface connection and unstable data transmission because the conductive glue is easily detached from the PDMS-based electrode during dynamic recording sessions such as moving or running. This study proposes to transform a commercial bio-potential electrode with a conductive snap (Medi-Trace?, COVIDIEN, Mansfield, MA, USA) into an FPDE using a CO2 laser and replica method technology. It does not damage skin and provides a convenient wire connection and stable data transmission for long-term use.The design proposed in this study focuses on both the comfort and performance of bio-potential acquisition systems in order to increase the autonomy of patients and improve their quality of life. Figure 1 depicts schematically the proposed bio-potential acquisition system, which includes an FPDE and a low-power recording circuit for portable ubiquitous selleck chemicals healthcare applications. All low-power recording circuits include state-of-the-art low-power micro-controllers, a low-power front-end acquisition chip fabricated using the standard CMOS process, and an SD card for portable use.Figure 1.Block diagram of the portable recording device.The front-end bio-potential acquisition chip included an ultra-low-power instrumentation amplifier (IA), filter, and gain stage.