Neural interfacing technology equips us with direct investigative tools to study brain function in both healthy and diseased states and this advanced understanding can help guide strategies for treating neurodegenerative disease. However, the body’s overwhelming immune response to inserted devices degrades recording and stimulating performances over time. Expanding our knowledge of the cell and tissue dynamics that occur around implanted microelectrodes can assist with developing improved device designs as well as novel interventions to mitigate unwanted biological responses. Using a combination of real-time in vivo two-photon microscopy, electrophysiology, and immunohistology, I will characterize the behavior and fate of previously understudied cell types, such as oligodendrocyte precursor cells and pericytes, around inserted electrode devices in the brain to understand their role in the foreign body response and further infer their contribution to brain inflammation and degenerative brain disease, such as Alzheimer’s disease and related disorders (ADRD).
Prior to pursing my Ph.D. at Pitt, I received my B.Sc. in Biomedical Engineering at the University of Florida. I worked in Dr. Christine Schmidt’s lab developing an optimized decellularization method for acellular peripheral nerve grafts. This method involved chemically inducing apoptosis in neurons and Schwann cells as opposed to using harsh chemical detergents, which compromise the extracellular matrix of the tissue and reduce the regenerative potential of the graft. This newly developed decellularization method can be applied to other tissues involved in organ regeneration such as heart, liver, and lung. Furthermore, I worked with a graduate student to develop injectable hydrogels from acellularized peripheral nerve tissue for spinal cord regeneration therapies.
1. Dubaniewicz, M., Eles, J.R., Lam, S., Shanshan, S., Cambi, F., Sun, D., Wellman, S.M., Kozai, T.D.Y. (2020). Inhibition of Na+/H+ exchanger modulates microglial activation and scar formation following microelectrode implantation. Journal of Neural Engineering. (submitted)
2. Chen, K., Wellman, S.M., Yaxiaer Y., Eles, J.R., Kozai, T.D.Y. (2020). In vivo spatiotemporal patterns of oligodendrocyte and myelin damage at the neural electrode interface. Biomaterials, 120526.
3. Wellman, S.M., Guzman, K., Stieger, K.C., Brink, L. E., Sridhar, S., Dubaniewicz, M.T., Li, L., Cambi, F., Kozai, T.D.Y. (2020). Cuprizone-induced oligodendrocyte loss and demyelination impairs recording performance of chronically implanted neural interfaces. Biomaterials, 239, 119842.
4. Wellman, S. M., Li, L., Yaxiaer, Y., McNamara, I., & Kozai, T. D. (2019). Revealing spatial and temporal patterns of cell death, glial proliferation, and blood-brain barrier dysfunction around implanted intracortical neural interfaces. Frontiers in neuroscience, 13, 493.
5. Cornelison, R. C., Wellman, S. M., Park, J. H., Porvasnik, S. L., Song, Y. H., Wachs, R. A., & Schmidt, C. E. (2018). Development of an apoptosis-assisted decellularization method for maximal preservation of nerve tissue structure. Acta biomaterialia, 77, 116-126.
6. Wellman, S. M., Cambi, F., & Kozai, T. D. (2018). The role of oligodendrocytes and their progenitors on neural interface technology: A novel perspective on tissue regeneration and repair. Biomaterials, 183, 200-217.
7. Wellman, S. M., & Kozai, T. D. (2018). In vivo spatiotemporal dynamics of NG2 glia activity caused by neural electrode implantation. Biomaterials, 164, 121-133.
8. Cornelison, R. C., Gonzalez-Rothi, E. J., Porvasnik, S. L., Wellman, S. M., Park, J. H., Fuller, D. D., & Schmidt, C. E. (2018). Injectable hydrogels of optimized acellular nerve for injection in the injured spinal cord. Biomedical Materials, 13(3), 034110.
9. Wellman, S. M., Eles, J. R., Ludwig, K. A., Seymour, J. P., Michelson, N. J., McFadden, W. E., Vazquez, A. L., & Kozai, T. D. Y. (2018). A materials roadmap to functional neural interface design. Advanced functional materials, 28(12), 1701269.
10. Wellman, S. M., & Kozai, T. D. (2017). Understanding the inflammatory tissue reaction to brain implants to improve neurochemical sensing performance. ACS Chemical Neuroscience, 8, 2578-2582.