Abstract

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Background & Purpose

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Peripheral neuropathy is challenging to model in vitro due to the complex architecture and functional requirements of nerves, including Schwann-cell myelination and electrophysiological signaling. The NerveSim® 3D nerve-on-a-chip system was developed to address these challenges by using human iPSC-derived sensory neurons (hSNs) and primary human Schwann cells (hSCs) in a microphysiological system (MPS). This study aims to validate neurite outgrowth, Schwann cell migration, myelination, and functional electrophysiology to support drug screening for neurotoxicity and neuroprotection.

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Methods

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1. Fabrication: PEG hydrogel scaffolds were crosslinked onto permeable membranes to create 3D nerve-on-a-chip structures.
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2. Cell Culture: hSN-hSC spheroids were cultured within the microchannel for 28 days, mimicking natural nerve fiber growth.
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3. Histological & Imaging Analysis:
   
   1. Immunohistochemistry (IHC): Measured neurite length, Schwann cell migration, and myelination.
   2. Transmission Electron Microscopy (TEM): Analyzed axonal ultrastructure.
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4. Electrophysiology Testing:
   
   1. Embedded Electrode Arrays (EEAs): Used for current stimulation and recording compound action potentials (CAPs).
   2. Functional Response to Capsaicin & Vincristine: Measured spike rates and nerve conduction velocity (NCV).

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Results

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• Histological Validation:
  
  • Neurite outgrowth >7mm, Schwann cell axonal alignment, and myelination confirmed by TEM and IHC.
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• Electrophysiological Response:
  
  • Capsaicin application increased spontaneous electrophysiological activity, demonstrating pain-related TRPV1 expression.
  • Vincristine dosing caused dose-dependent declines in nerve conduction velocity, mimicking axonopathy.
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• Functional Insights:
  
  • Electrophysiology matched clinical metrics, making NerveSim® a predictive tool for human nerve responses.

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Conclusion

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The NerveSim® 3D nerve-on-a-chip platform successfully models human peripheral nerve function, making it a valuable tool for drug discovery, neurotoxicity assessment, and neuroprotection screening. Future studies aim to expand compound screening libraries to predict drug mechanisms based on electrophysiology data.