Stretchable gold nanowire-based cuff electrodes for low-voltage peripheral nerve stimulation

Abstract

Objective. Electrical stimulation of the peripheral nervous system (PNS) can treat various diseases and disorders, including the healing process after nerve injury. A major challenge when designing electrodes for PNS stimulation is the mechanical mismatch between the nerve and the device, which can lead to non-conformal contact, tissue damage and inefficient stimulation due to current leakage. Soft and stretchable cuff electrodes promise to tackle these challenges but often have limited performance and rely on unconventional materials. The aim of this study is to develop a high performance soft and stretchable cuff electrode based on inert materials for low-voltage nerve stimulation. Approach. We developed 50 µm thick stretchable cuff electrodes based on silicone rubber, gold nanowire conductors and platinum coated nanowire electrodes. The electrode performance was characterized under strain cycling to assess the durability of the electrodes. The stimulation capability of the cuff electrodes was evaluated in an in vivo sciatic nerve rat model by measuring the electromyography response to various stimulation pulses. Main results. The stretchable cuff electrodes showed excellent stability for 50% strain cycling and one million stimulation pulses. Saturated homogeneous stimulation of the sciatic nerve was achieved at only 200 mV due to the excellent conformability of the electrodes, the low conductor resistance (0.3 Ohm sq−1), and the low electrode impedance. Significance. The developed stretchable cuff electrode combines favourable mechanical properties and good electrode performance with inert and stable materials, making it ideal for low power supply applications within bioelectronic medicine.

Biomedical Microtechnologies Beyond Scholarly Impact

“…Soft elastomers such as polydimethylsiloxane silicone (PDMS), popularly used as biocompatible molded external shell for implanted devices of different sorts [21,22], have now been shown to be compatible with full integration into wafer-scale microfabrication processes [23]. Examples of devices microfabricated on silicone elastomer include implantable neural interfaces for the central nervous system [24,25] and peripheral nerves [26], as well as wearable electronic sensors that conform the human skin [27]. Other important research directions stem from the inclusion of biodegradable electronic materials in transient implantable devices that are designed to be metabolized once they have served their purpose inside the body [28].…”

Flexible Electronics and Devices as Human–Machine Interfaces for Medical Robotics

“…[310,311] Recent advancements in soft and nanomaterials have opened up more options for flexible recording electrodes, like conductive polymers (e.g., PEDOT) [302,312] and nanomaterial composites (metalbased, CNT, graphene). [313][314][315][316][317] Apart from the conductive functional materials, the insulative packaging materials are also a critical part of sensing recorders. Many popular insulating soft materials have been used for packaging sensing electrodes, [318] such as PI, [319,320] PDMS, [321,322] and hydrogel, [323,324] as they have suitable mechanical, dielectric, and biological properties.…”

“…[542] The wraparound peripheral nerve interface can reduce foreign body reactions caused by insertion. [58,302,314,549] As an example, Figure 15E demonstrates a wireless bioresorbable electronic system for peripheral neuron modulations. Utilizing a deposited layer of Mg embedded in insulting polymer to deliver electrical stimuli from the receiver antenna to the tissue, the system successfully enhanced neuroregeneration and functional recovery in rodent models (Figure 15F).…”

Recent Advances in 1D Nanomaterial‐Based Bioelectronics for Healthcare Applications

“…Lienemann et al prepared 300 nm diameter/3–20 μm long Au nanowire electrodes on a PDMS substrate by transfer printing. [ 117 ] The electrode exhibited a stable performance with a sheet resistance of 10 Ω sq −1 over 1,000 cycles under 50% strain. Moreover, as the electroplating of Pt on Au nanowires decreases the impedance, the device could be driven with a low voltage (200 mV).…”

“…An adaptive neural ribbon electrode was implanted into the various nerves having different diameters (peroneal, tibial, sural, and sciatic nerves with 300-600 μm) of Sprague Dawley rats and the electrode could record electrical signals. Some of the mentioned works [113,[117][118][119] did not consider biocompatibility in their researches.…”