A Silicon Diaphragm Sensor for Smart Stents: Combining Polymer-Like Flexibility with Crystalline Stability for Chronic in-Vivo Monitoring

Long-term stability of wireless pressure sensors is critical for smart stents monitoring atherosclerosis, but conventional polymer diaphragms exhibit swelling and creep. These instabilities cause significant baseline and sensitivity drift, limiting clinical reliability. We present an LC wireless sensor using a monocrystalline silicon diaphragm, monolithically fabricated on an SOI wafer via a DRIE process. Rigorous characterization demonstrates the silicon diaphragm is inherently stable under stress and in aqueous environments, unlike polymers. The sensor thus shows minimal frequency drift and negligible sensitivity changes over extended periods, providing a crucial enabling technology for next-generation smart stents.