Description
- Abstract:
- Objective: Traumatic brain injury (TBI) results when external forces exert strain on the brain, resulting in cell death, inflammation, and long-term neurological effects. To screen therapeutics for TBI, there is a need for biomimetic, high-throughput models that simulate blunt TBI. A previously established 3D in vitro cortical spheroid model containing the cells present in the brain and exhibiting brain-like stiffness and electrical activity was employed to address this need. Here, we present a novel silicone indenter and 3D-printed mechanical assembly to simulate blunt TBI in cortical spheroids, enabling reproducible and scalable injury delivery. Methods: Primary rat cortical cells (8000 cells/well) were seeded into 96-well agarose micro-molds to generate spheroids. Silicone indenters with 96 pegs were designed to impact spheroids at 13-15 days in vitro. Impacting devices were designed in Fusion360 and 3D printed with polylactic acid on a Prusa i3 MK3S+ printer. Viability was assessed via ATP quantification and Ethidium Homodimer-1 staining. Neuronal and glial responses were evaluated through β-III Tubulin (neurites), Glial Fibrillary Acidic Protein (astrocytes), and Isolectin-B4 (microglia), followed by confocal imaging, ImageJ and graph theory analyses, and statistical evaluation. Results: Silicone indenters were integrated with one of two custom-designed bistable compliant mechanisms (BiCM1 or BiCM2), both of which successfully delivered mechanical impacts to cortical spheroids. Silicone indenters induced strain levels ranging from 25% to 50%. The approximate force required to deploy the BiCMs were 9N for BiCM1 and 25N for BiCM2. BiCM2 exhibited a high strain rate of approximately 400 to 600 s-1. Spheroids subjected to impact exhibited immediate and sustained astrocyte activation, neurite degeneration, and reduced viability lasting at least 72 hours, with BiCM2-impacted spheroids experiencing more pronounced cellular damage. Repeated impacts also resulted in cell death. Conclusions: This study demonstrates a novel platform for simulating blunt TBI in cortical spheroids. Impacted spheroids resulted in reduced viability and increased neuroinflammation, with higher severity injuries resulting in increased spheroid damage. Ongoing work includes mechanical optimization to improve experimental reproducibility. This platform provides a promising tool for mechanistic studies and therapeutic screening in TBI research.
- Notes:
- Thesis (Sc. M.)--Brown University, 2025
Citation
Vecchio, Francesca B.,
"Design and Implementation of a Device to Simulate Blunt Traumatic Brain Injury Using a 3D In Vitro Cortical Spheroid Model"
(2025).
Biomedical Engineering Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:n7m6ajf5/
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Biomedical Engineering Theses and Dissertations
Theses and Dissertations for the Biomedical Engineering department....