A Syringe Tumbler for Ink Resuspension (STIR)
Abstract/Contents
- Abstract
- Embedded 3D bioprinting is advancing the field of regenerative medicine through the ability to create patient-specific tissues and organs that can fulfill the organ donor shortage. However, the process of 3D bioprinting is currently limited by cell settling within bioinks since printing of human-scale organs can take hours–or even days–to complete. To address the problem of cell settling, I designed and developed Syringe Tumbler for Ink Resuspension (STIR), a mixing system with a Zero-Dead-Volume (ZDV) magnetic tumbler that can prevent settling and maintain high cell viability throughout long-duration prints. In this thesis, cell settling at various mixing speeds and patterns are characterized by mixing of fluorescent beads that resemble embryoid bodies–a particularly challenging object for cellular mixing due to their large size. True cellular mixing is further characterized by the use of fibroblast cells. The effects of mixing are analyzed through cell concentration analysis and staining to ascertain cell viability while using the device. From the system characterization, I identified back-and-forth mixing as the most consistent method as it allows for improved ink homogeneity at lower mixing speeds, thus reducing the shear stress induced on cells. More specifically, by defining the degree of mixing through thresholding in image analysis, the back-and-forth mixing improved the homogeneity of a 10 mg/mL fibrinogen ink embedded with fluorescent beads by 33.68% over a 15.6 second window, whereas settling reduced the ink homogeneity by 48.84% over the same time frame. Similarly, for long-term cellular prints with and without STIR, a reduced variance in cell concentration was experienced. This suggests that STIR can yield more predictable tissue compositions for both short-duration and long-duration prints. To test the effects of tissue composition, I designed a tissue in the form of a flower, where each petal was to be printed with a cellular layer. The flower-shaped tissue was successfully printed without cells, and two leaflets were printed with fibroblast cells. Evidence of compaction was detected for the cellular constructs, highlighting the first successful tissue created with STIR. Future works will include repeating the tests developed in this thesis in order to confirm my initial findings.
Description
| Type of resource | text |
|---|---|
| Date created | May 2023 |
| Publication date | July 1, 2023 |
Creators/Contributors
| Author | Sanabria, Coco |
|---|---|
| Thesis advisor | Skylar-Scott, Mark |
Subjects
| Subject | 3D bioprinting |
|---|---|
| Subject | cell sedimentation |
| Subject | cell settling |
| Subject | ink resuspension |
| Genre | Text |
| Genre | Thesis |
Bibliographic information
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- User agrees that, where applicable, content will not be used to identify or to otherwise infringe the privacy or confidentiality rights of individuals. Content distributed via the Stanford Digital Repository may be subject to additional license and use restrictions applied by the depositor.
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 4.0 International license (CC BY-NC).
Preferred citation
- Preferred citation
- Sanabria, C. (2026). A Syringe Tumbler for Ink Resuspension (STIR). Stanford Digital Repository. Available at https://purl.stanford.edu/mg231ry3540. https://doi.org/10.25740/mg231ry3540.
Collection
Undergraduate Theses, School of Engineering
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