2024-12-18 オランダ・デルフト工科大学
<関連情報>
- https://www.tudelft.nl/en/2024/eemcs/advancements-in-neural-implant-research-enhance-durability
- https://www.nature.com/articles/s41467-024-55298-4
シリコンICの寿命と固有の気密性について:加速エージングおよび埋め込み試験後のベアダイおよびPDMSコーティングICの評価 On the longevity and inherent hermeticity of silicon-ICs: evaluation of bare-die and PDMS-coated ICs after accelerated aging and implantation studies
Kambiz Nanbakhsh,Ahmad Shah Idil,Callum Lamont,Csaba Dücső,Ömer Can Akgun,Domonkos Horváth,Kinga Tóth,Domokos Meszéna,István Ulbert,Federico Mazza,Timothy G. Constandinou,Wouter Serdijn,Anne Vanhoestenberghe,Nick Donaldson & Vasiliki Giagka
Nature Communications Published:02 January 2025
DOI:https://doi.org/10.1038/s41467-024-55298-4
Abstract
Silicon integrated circuits (ICs) are central to the next-generation miniature active neural implants, whether packaged in soft polymers for flexible bioelectronics or implanted as bare die for neural probes. These emerging applications bring the IC closer to the corrosive body environment, raising reliability concerns, particularly for chronic use. Here, we evaluate the inherent hermeticity of bare die ICs, and examine the potential of polydimethylsiloxane (PDMS), a moisture-permeable elastomer, as a standalone encapsulation material. For this aim, the electrical and material performance of ICs sourced from two foundries was evaluated through one-year accelerated in vitro and in vivo studies. ICs featured custom-designed test structures and were partially PDMS coated, creating two regions on each chip, uncoated “bare die” and “PDMS-coated”. During the accelerated in vitro study, ICs were electrically biased and periodically monitored. Results revealed stable electrical performance, indicating the unaffected operation of ICs even when directly exposed to physiological fluids. Despite this, material analysis revealed IC degradation in the bare regions. PDMS-coated regions, however, revealed limited degradation, making PDMS a suitable IC encapsulant for years-long implantation. Based on the new insights, guidelines are proposed that may enhance the longevity of implantable ICs, broadening their applications in the biomedical field.
