Abstract
Background & Purpose
Current preclinical drug screening methods, including animal models and 2D cultures, fail to replicate the complex architecture and functional outputs of human peripheral nerves. Schwann cell myelination and electrophysiological measurements are crucial for evaluating nerve health and neurotoxicity. To address these challenges, 28bio developed NerveSim®, a 3D microphysiological system (MPS) that mimics human peripheral nerve anatomy and function. This study validates the NerveSim® myelinated nerve-on-a-chip model by analyzing neurite outgrowth, Schwann cell migration, and myelination.
Methods
- NerveSim® Fabrication & Culture:
- Human iPSC-derived sensory neurons (hSNs) and primary Schwann cells (hSCs) were co-cultured in a dual hydrogel system.
- Spheroids were grown for 28 days to promote axon growth and Schwann cell myelination.
- Morphological & Structural Analysis:
- Immunohistochemistry (IHC): Measured neurite length, Schwann cell migration, and myelination.
- Transmission Electron Microscopy (TEM): Evaluated Schwann cell-myelinated axon ultrastructure.
- Future Neurotoxicity Testing:
- Planned 7-day exposure to chemotherapy drugs known to cause peripheral neuropathy.
- Validation of electrophysiology (EPHYS) metrics using custom embedded electrode arrays (EEA).
Results
- Successful Schwann Cell Migration & Myelination:
- Neurite outgrowth exceeded 7mm, with Schwann cell migration greater than 6mm into the nerve channel.
- Schwann cells aligned along axons, a critical prerequisite for myelination.
- Myelination was confirmed near the spheroid bulb and extended up to 2mm into the axon channel.
- Imaging & Structural Analysis:
- IHC analysis showed robust neurite length (βIII-Tubulin), Schwann cell distribution (S100), and myelin presence (MBP).
- TEM images validated Schwann cell-myelinated axons, confirming a mature nerve structure.
Conclusion
The NerveSim® platform successfully replicates human peripheral nerve function, making it a powerful tool for preclinical drug screening. Future studies will incorporate chemotherapy-induced neurotoxicity assessments and expand electrophysiology validation. This human-relevant screening system has the potential to improve drug safety assessments and clinical translation.
