biostudies-literatureYan DNational Institutes of HealthNIH HHSe2200311https://www.ebi.ac.uk/biostudies/studies/S-EPMC9167574biostudies-literatureUnknown18(21)Peripheral nerve mapping tools with higher spatial resolution are needed to advance systems neuroscience, and potentially provide a closed-loop biomarker in neuromodulation applications. Two critical challenges of microscale neural interfaces are 1) how to apply them to small peripheral nerves, and 2) how to minimize chronic reactivity. A flexible microneedle nerve array (MINA) is developed, which is the first high-density penetrating electrode array made with axon-sized silicon microneedles embedded in low-modulus thin silicone. The design, fabrication, acute recording, and chronic reactivity to an implanted MINA, are presented. Distinctive units are identified in the rat peroneal nerve. The authors also demonstrate a long-term, cuff-free, and suture-free fixation manner using rose bengalSmall (Weinheim an der Bergstrasse, Germany)Ultraflexible and Stretchable Intrafascicular Peripheral Nerve Recording Device with Axon-Dimension, Cuff-Less Microneedle Electrode Array.PMC91675741OT2OD026585OT2 OD0249071OT2OD024907OT2 OD026585Welle EJJiman AAChestek CAHavton LAKemp SWPBottorff ECBruns TMSeymour JPPatel PRYoon EYan DRatze DCMeli DfalseUltraflexible and Stretchable Intrafascicular Peripheral Nerve Recording Device with Axon-Dimension, Cuff-Less Microneedle Electrode Array.Peripheral nerve mapping tools with higher spatial resolution are needed to advance systems neuroscience, and potentially provide a closed-loop biomarker in neuromodulation applications. Two critical challenges of microscale neural interfaces are 1) how to apply them to small peripheral nerves, and 2) how to minimize chronic reactivity. A flexible microneedle nerve array (MINA) is developed, which is the first high-density penetrating electrode array made with axon-sized silicon microneedles embedded in low-modulus thin silicone. The design, fabrication, acute recording, and chronic reactivity to an implanted MINA, are presented. Distinctive units are identified in the rat peroneal nerve. The authors also demonstrate a long-term, cuff-free, and suture-free fixation manner using rose bengal2022-01-01T00:00:00Z2022 May2025-04-27T04:18:38.818Z2025-04-06T19:06:17.716ZS-EPMC91675743549152210.1002/smll.202200311