Fabrication of barbed-microneedle array for bio-signal measurement

Microneedle array electrode (MNAE) have demonstrated high reliability in signal recording and electrode-skin interface impedance, making them a promising option for bio-signal sensing. In this study, we fabricated barbed microneedles for MNAE using standard photolithography and PDMS thermal expansion techniques. By comparing experiments with Ag/AgCl electrodes, we observed the following findings: (1) The force required to pull out barbed MNs from a soft parafilm membrane was significantly higher than that for barbless MNs. (2) We successfully used these MNAE prototypes to record electrocardiograms (ECGs) both in static and dynamic states, resulting in higher amplitudes. Additionally, we measured EII and evaluated the performance of the proposed dry microneedle electrodes compared to traditional wet electrodes with Ag/AgCl electrode.