Biocompatibility Testing of Liquid Metal as an Interconnection Material for Flexible Implant Technology.

Katharina Foremny,Michaela Kreienmeyer,Wim Deferme,Theodor Doll,Steven Nagels

doi:10.3390/nano11123251

Katharina Foremny, Michaela Kreienmeyer + Show 3 more

Open Access

https://doi.org/10.3390/nano11123251

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Abstract

Galinstan, a liquid metal at room temperature, is a promising material for use in flexible electronics. Since it has been successfully integrated in devices for external use, e.g., as stretchable electronic skin in tactile sensation, the possibility of using galinstan for flexible implant technology comes to mind. Usage of liquid metals in a flexible implant would reduce the risk of broken conductive pathways in the implants and therefore reduce the possibility of implant failure. However, the biocompatibility of the liquid metal under study, i.e., galinstan, has not been proven in state-of-the-art literature. Therefore, in this paper, a material combination of galinstan and silicone rubber is under investigation regarding the success of sterilization methods and to establish biocompatibility testing for an in vivo application. First cell biocompatibility tests (WST-1 assays) and cell toxicity tests (LDH assays) show promising results regarding biocompatibility. This work paves the way towards the successful integration of stretchable devices using liquid metals embedded in a silicone rubber encapsulant for flexible surface electro-cortical grid arrays and other flexible implants.

Highlights

Enrica VernèFlexible surface electro-cortical grid arrays (ECoG) are a valuable alternative to penetrating multi-electrode arrays (MEA)
We present a first study on the usability of ultraviolet light (UV) sterilization, ethanol sterilization and steam sterilization for galinstan samples
= 18; of dotted line is at 70%; and rubberof measured with Lactate dehydrogenase (LDH) assay; N = 6.and silicone rubber measured with LDH assay; N = 6

Summary

Introduction

Flexible surface electro-cortical grid arrays (ECoG) are a valuable alternative to penetrating multi-electrode arrays (MEA). Their usability in both acute and chronic recordings is under investigation for numerous material combinations [1,2,3,4] and their potency for good recordings has been shown as well [2,3]. They are limited in their flexibility by the rigid materials used for their conductive pathways. Due to its composite nature, this approach can never attain conductivities neighboring the order of magnitude of bulk metals

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