Flexible Electrical Patches Image
A new ‘smart’ flexible electric patch (ePatch) addresses the challenges posed by existing electrical field (EF) stimulation devices. (Credit: Terasaki Institute)

A new ‘smart’ flexible electric patch (ePatch) addresses the challenges posed by existing electrical field (EF) stimulation devices and offers many uniquely advantageous features. The team first chose silver nanowires as electrodes, which not only provide antibacterial properties but also deliver high conductivity under strain.

They next chose to embed the electrodes in alginate, a gelatinous substance which maintains good moisture levels and biocompatibility and is presently used in absorbent surgical dressings.

By a chemical modification of the alginate and the addition of calcium, they were able to produce a material that would increase electrode stability and function. By further adjustment of the silver nanowire/modified alginate ratio, they were able to obtain a flexible, precisely printable gel, or bio-ink, which would produce a patch with customizable conformity to various wound shapes and sizes. In addition, the calcium which was added to the mix induced cell proliferation and migration to the wound site, which in turn would promote blood vessel formation.

To fabricate the e-Patch, a template was layered onto a silicone sheet and the bio-ink was deposited onto the template. Upon solidification of the bio-ink, the template was removed.

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