Shrinking stretchable metallic wiring to fit in a nerve

Flexible, stretchable electronics, such as smart textiles, require flexible, stretchable wiring. For wiring to be implanted into a nerve to investigate activity, it must be smaller than the nerve, which have a diameter of a millimeter or less, while remaining soft and flexible.

Badhe et al. created stretchable metallic wiring small enough to implant in a nerve. They adapted photolithographic processes to nontraditional materials, which allowed them to pattern wiring with resolution smaller than 10 micrometers, an order of magnitude smaller than previously reported, on an electrospun nanofiber mesh substrate. A silicone coating of the nanofiber mat encapsulated the wiring.

“The technology that we used allowed us to make them in a smaller scale than what has been shown before,” said author Alexandra Joshi-Imre.

The authors covered the nanofibers with thin coats of gold to create the wiring. Although thinner metal coats are less conductive, they allow a wire to be more flexible. The thinnest gold coating the authors applied was 25 nanometers thick, but these wires still exhibited metallic conductive behavior.

Testing demonstrated the wiring was electrically functional.

The authors hope to characterize the mechanical properties of these structures. They will work with collaborators to test the implantation of these structures into the nerves of small animal models.

The structures may find use beyond intraneural applications, such as on-skin sensors and other wearable electronics.

“A lot of applications, especially in the biomedical field, would benefit from scaled down stretchable wiring,” said author Yutika Badhe. “We are demonstrating the capacity to do that.”

Source: “Lithographically patterned stretchable metallic microwiring on electrospun nanofiber mats,” by Yutika Badhe, Pedro E. Rocha-Flores, Walter E. Voit, David Remer, Lauren Costella, and Alexandra Joshi-Imre, JVST: B (2021). The article can be accessed at https://aip.scitation.org/doi/full/10.1116/6.0001279 .

This paper is part of the 64th International Conference on Electron, Ion, And Photon Beam Technology and Nanofabrication, EIPBN 2021 Collection, learn more here: https://avs.scitation.org/toc/jvb/collection/10.1116/jvb.2021.EIPBN2021.issue-1 .