Miniaturized Ultra-Soft Stretchable Neural Probes

The rise of implantable bioelectronics have shown promising potential in neuroprosthetics (artificial sensory or motor function), treating neurological disorders (e.g., chronic pain, epilepsy, Parkinson), and advancing new devices for virtual and augmented reality [1]. Current neural interface technologies typically use rigid probes that causes undesired foreign body response and scar tissue formation. This is due to a mechanical mismatch between rigid probes (young’s modulus ranging from ~1 MPa to several GPa) and the biological tissue (~1 to 100 kPa) [2]. To address this, new materials and microfabrication techniques are needed to engineer soft and stretchable electrodes with geometries that are compliant when interfacing with the nerve. In this work, we present an ultra-high-density stretchable neural probe, which was engineered using the deep-ultraviolet (DUV) laser patterning a soft and stretchable composite consisting of a gold nanowire conducting mesh embedded into a silicone-based elastomer substrate. The electrodes exhibited good electromechanical performance and its young’s modulus (~55 kPa) matches the mechanical properties of the targeted peripheral nerve. The promising electrode performance suggests a potential in establishing a new paradigm in chronic neural interfacing with far-reaching implications for emerging medical treatments of peripheral nervous system (PNS) and other related conditions.<br/><br/><br/>[1] Q. Zeng and Z. Huang, <i>Adv. </i><i>Funct. Mater</i>. 2301223 (2023); M. Kim et al., <i>Acc. Chem. Res</i>. 5435-5447 (2024).<br/><br/>[2] S.P. Lacour, G. Courtine, and J. Guck, <i>Nat. </i><i>Rev. Mater</i>. <b>1</b>, 1-14 (2016); K. Tybrandt et al., <i>Adv. </i><i>Mate.</i><b> 30</b>, 1706520 (2018); S.H. Sunwoo et al., <i>Matter, </i><b>3</b>, 1923-1947 (2020); C.M. Tringides and D.J. Mooney,<i> Adv. Mate.</i><b> 34, </b>2107207 (2022).