Soft polymer nerve cuff tested by Imperial and EPFL, using Advent PTFE-insulated silver wires

Using Advent's 125 μm diameter PTFE-insulated silver wire, a collaborative team from Imperial College London and EPFL report a soft peripheral nerve cuff array designed to improve how selectively specific nerve bundles can be stimulated after peripheral nerve injury. The design keeps most electrodes outside the nerve, while adding a single double-sided interfascicular electrode placed between fascicles.
The work is published in Bioelectronic Medicine (Ben M’Rad et al., 2025).

The Science Made Simple
Peripheral nerves act like multi-core cables. Inside each nerve, bundles of fibres carry signals to and from muscles and skin. If you stimulate the whole nerve at once, you can trigger the wrong fibres. This study tests a cuff that wraps around the nerve, plus one tiny element placed between nerve bundles, to help steer current more precisely.

Background and aims

Damage to peripheral nerves can severely disrupt movement, sensation and organ function, and current electrical implants often struggle to stimulate only the desired nerve fibres without unwanted side effects. The SPIFEC project set out to improve this “spatial selectivity” challenge by modifying an existing soft polymer cuff design so it could better target specific nerve fascicles while remaining as gentle and stable as possible on the tissue.

A soft cuff with a small twist

The new device, called SPIFEC, is a soft wrap‑around cuff that sits on the outside of the nerve like a sleeve. Its key twist is adding one very small element that passes between the internal bundles of the nerve, giving the system a better “line of sight” to specific pathways without turning the whole design into a deeply penetrating implant.

Role of Advent’s silver wire

The device uses soft polymer electrodes and a flexible insulating layer so the cuff can move with the nerve. To link the cuff to external stimulation and recording equipment, the researchers integrated PTFE-insulated 125 μm silver wires supplied by Advent Research Materials.

How they tested the idea

The team tested the cuff ex vivo on isolated rat sciatic nerves, stimulating through the cuff and measuring responses in nerve branches. Imaging was also used to confirm interfascicular placement of the penetrating electrode. Compared with a similar cuff without the interfascicular element, SPIFEC showed improved fascicular selectivity in these lab tests.

Why it matters

This is early stage, lab-based research, so it does not show clinical outcomes in patients. It does show a practical route to improving selectivity while keeping a largely extraneural design, which is relevant for future neuroprosthetic and peripheral nerve stimulation systems.

Read the full open‑access article in Bioelectronic Medicine:
“Using a single penetrating interfascicular electrode to improve spatial selectivity of an extraneural polymeric cuff array,” 2025, 11:29, doi: 10.1186/s42234-025-00193-6.