Objective:  A novel dry electrode is developed to improve the comfortability and the capability of alleviating motion interference by combining microneedles array (MNA) with flexible substrate.  Methods:   Silicon MNA with sharp tips and limited height is fabricated and transferred on a flexible Polydimethylsiloxane (PDMS) substrate through bonding. Poly (3, 4-ethylenedioxythiophene) doped with poly (styrenesulfonate) (PEDOT/PSS) is coated on the surface of flexible MNA to form a conductive layer.   Results:  Flexible dry electrode with 1.2 cm diameter is successfully fabricated. The mean impedance magnitudes (measured on skin) at 10 Hz are   $61.2 \pm 31.3$    kΩ·cm 2  for flexible dry electrode, while the values are    $114.9 \pm 36.1$   kΩ·cm 2  for wet electrode and   $335.7 \pm 110.5$   kΩ·cm 2  for flexible planar dry electrode, respectively. In the process of biopotential recording, the flexible dry electrode has the similar performance as that of wet electrode. It exhibits more stable recording stability than rigid dry electrode in the movement state.  Conclusion:  By integrating flexible PDMS substrate, sharp and hard MNA structure, as well as PEDOT/PSS coated surface together, a novel dry electrode is developed to meet the comfortable and antimotion interference requirement of wearable equipment.   Significance:  The novel flexible dry electrode provides a simple and comfortable method to record biopotential signals in daily life.
['He Zhang', 'Weihua Pei', 'Yuanfang Chen', 'Xuhong Guo', 'X. F. Wu', 'Xiaowei Yang', 'Hongda Chen']
A Motion Interference-Insensitive Flexible Dry Electrode