UC Riverside

As the human population ages and expands, neurological disorders have grown to present one of our most pervasive and debilitating global health burdens. In an effort to elucidate and remediate these poorly understood pathologies, researchers have largely relied on classical disease modeling techniques, such as animal proxies, tissue explantation, and traditional cell culture. Unfortunately, the clinical translatability of these approaches is limited by their inability to faithfully recapitulate the complexity of endogenous disease environments. As such, recent efforts have shifted toward the development of patient-specific neural tissue models in vitro, which offer an effective compromise between utility and physiological accuracy. As demonstrated by our prior studies, functional neural tissue can be engineered in vitro through the mechano-electrical stimulation (MES) of human neural stem cells (hNSCs). A biocompatible, piezoelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) nanofibrous scaffold enables the MES of hNSCs, inducing their multiphenotypic differentiation into the neurons, oligodendrocytes, and astrocytes which comprise tissues in the central nervous system (CNS). Despite their well-demonstrated physiological functionality, the engineered nerve tissue exhibited minimal alignment and stunted axonal elongation. In this regard, this study describes a novel approach developed for optimizing the alignment, length, and connectivity of axonal outgrowth in engineered nerve tissue by leveraging the use of polydimethylsiloxane (PDMS) microwells for guided cell seeding and tissue morphogenesis. A biochemical factor regimen was optimized to further augment the length and myelination of neurite outgrowth. The resulting neurons and their interactions with glial cells resemble the morphological and functional features of native nerve tissues as expected. To demonstrate the efficacy of our engineered nerve tissue as a neurological disease model, we integrated the biochemical toxicants of cuprizone, inflammatory cytokines, and lysophosphatidyl choline (LPC) to simulate the demyelinating lesions characteristic of Multiple Sclerosis (MS). Through imaging analysis and microelectrode array (MEA) electrophysiology, we found that the simulated diseased condition adequately emulated the tissue degeneration observed in clinical manifestations of MS.