A Rapid-Prototyping Platform for Active Stents Utilizing Device Decapsulation for Miniaturization

This paper presents an ultra-miniaturized PCB-based implementation for prototype testing of an active stent. Cardiovascular diseases are the leading cause of mortality in developed nations and blocked blood vessels are nowadays routinely cleared with minimal-invasive stent-implantation. Nevertheless, restenosis may occur, hence continuous monitoring of the most critical biomarkers is beneficial. Adding an active electronic sensor system to the stent renders it to become an active stent, which allows for long-term monitoring with minimum burden on the patient. The constraints include minimum volume, very limited power budget as well as wireless power and data telemetry. In this paper, we present a prototype implementation using only commercial components, which reduces prototyping time and cost as compared to a final integrated solution. Component volume was reduced by dissolving the packages and bonding the bare dies directly to the miniaturized PCB, resulting in a total system volume of 4.95 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>, The paper focuses on the miniaturization process based on combinations of wet etching utilizing nitric acid (HN0<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>) and peroxymonosulfuric acid (H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>S0<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf>) known as Piranha solution. A functional prototype was manufactured and the performance was verified in measurements.