ORIGINAL RESEARCH article

Front. Bioeng. Biotechnol.

Sec. Biomechanics

Volume 13 - 2025 | doi: 10.3389/fbioe.2025.1622927

This article is part of the Research TopicEnhancing Durability of Bioelectronic Implants: Innovations in Encapsulation Materials and MethodsView all articles

Failure behavior of polymer microelectrode arrays encapsulated with conventional ALD and 3D-ALI barriers

Provisionally accepted
  • University of Connecticut, Storrs, United States

The final, formatted version of the article will be published soon.

As implantable electronics become thinner, softer, and more flexible, there is an increasing need for encapsulation strategies which enable these next-generation devices to survive for sufficient durations in the implanted environment. Atomic layer deposited (ALD) films of metal oxides have been studied for this purpose but suffer from intrinsic incompatibilities with soft and flexible substrates. Additionally, conventional fabrication processes often leave exposed sidewalls vulnerable to moisture permeation, undermining the effectiveness of the encapsulation. In this work, we report an encapsulation method based on atomic layer infiltration (ALI) which eliminates exposed sidewalls while remaining compatible with active microelectrodes for stimulation and recording. We compare the lifetime of sidewall-encapsulated (i.e., 3D) ALI devices under accelerated aging conditions to unencapsulated and conventional ALD-encapsulated groups. Overall, we find that while the 3D-ALI encapsulation successfully reduces sidewall vulnerabilities and offers qualitative improvements in degradation behavior compared to ALD, it did not significantly extend device lifespan. Taken together, these findings highlight both the promise of the 3D-ALI strategy and the need for further study and optimization.

Keywords: Atomic layer deposition, vapor phase infiltration, Atomic layer infiltration, Flexible bioelectrodes, Lifetime analysis, Failure mode analysis

Received: 06 May 2025; Accepted: 09 Jul 2025.

Copyright: © 2025 Niemiec, Bayansal, Biyikli and Kim. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Kyungjin Kim, University of Connecticut, Storrs, United States

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