Self-rollable Polymer Stent Integrated with Wireless Pressure Sensor for Real-time Monitoring of Cardiovascular Pressure

In this paper, we propose a self-rollable polymer (SU-8) stent integrated with a passive LC pressure sensor for the uninterrupted monitoring of cardiovascular pressure. The design of the LC pressure sensor and polymer stent was optimized by varying the turns of inductor and the stent thickness. A wireless pressure sensor with 30 turns of coils was selected based on the experimental results of inductance and radial force measurements. The sensor was fabricated simultaneously with a stent structure with a thickness of 40 µm on a two-dimensional plane using conventional micromachining processes. The fabricated smart stent was placed inside a silicon tube, and its performance was evaluated as a function of working distance (0–11 mm), working pressure (0–100 mmHg), and different media (air, DI water, and saline). After the preliminary experiment, the entire stent device was encapsulated with a thin parylene C layer, and improvements in biocompatibility were confirmed using a viability test with human umbilical vein endothelial cells. The proposed smart stent is expected be widely used in medical applications owing to its structural excellence.