Carotid artery monitoring patch using a supercapacitive pressure sensor with piezoelectricity

The carotid artery should be frequently examined to prevent sudden death by stroke. However, ultrasonography is limited because medical staff must perform the procedure directly in the hospital. Unfortunately, severe situations exist in which people miss treatment because of being unaware that their blood vessels are abnormal. Therefore, this work presents a patch-type pressure sensor using a supercapacitor and a poly (vinylidene fluoride-trifluoroethylene) (PVDF-TrFE). When PVDF-TrFE with 30 µm thickness as nanofibers exists in the electrolyte gel of the supercapacitor, the polarization of electrolyte ions is induced, and these ions move to the electrode fastly. Thus, the supercapacitive-type pressure sensor (sCPS) for pulse monitoring can detect slight skin fluctuation and show a pulse waveform with high accuracy. Furthermore, this study demonstrates a statistically significant equation that can calculate blood pressure from a pulse waveform. Finally, it is verified that sCPS detects differences in pulse waveforms due to various cardiovascular diseases.