Item Details

title

The Underlying Mechanisms Governing Bioink Printability for Extrusion-based Bioprinting and Application to the Regeneration of Bone and Tooth Tissues

author

Gillispie, Gregory James

abstract

Bioprinting, an advantageous regenerative medicine manufacturing technique, is limited primarily by the dearth bioinks suitable for use. There is a need for bioink development and improvements to the bioink development process. This process is difficult due to the quantity of both bioactivity and printability parameters researchers must consider. Additionally, there is a poor understanding of how these parameters, especially rheology, influence final printing outcomes. The study of these parameters is further limited due to insufficient analysis methods. Throughout this work, several novel printing outcome assessments have been developed, culminating in a comprehensive, bioink-specific artifact. First, the effect of tan(δ) on a gelatin-alginate bioink was established, with higher values leading to higher filament uniformity and lower values leading to higher shape fidelity, but these results showed a lack of applicability to other bioinks. Next, speed ratio was shown to have a dominating effect on printing outcomes relative to feedrate and flowrate using a GelMA-Gellan Gum bioink and cell concentration was shown to have no effect up to 40 x 106 cells/mL. Using a wide range of bioinks and rheological measures, the effect of rheology on printing outcomes was investigated, with G’, tan(δ), yield stress, shear thinning, and recovery behaviors each shown to play a role. Lastly, tissue-specific bioactivity was improved upon by conjugating a synthetic BMP-peptide to a GelMA-based bioink, demonstrating improved DPSC osteogenic differentiation in both growth and osteogenic media. In totality, this work has made significant contributions in bioink development, specifically regarding printability assessment techniques, the underlying mechanisms impacting printability, and the bioactivity of tissue-specific bioinks.

subject

bioprinting

bone

hydrogel

printability

regenerative medicine

tissue engineering

contributor

Lee, Sang Jin (committee chair)

Almeida-Porada, Graca (committee member)

Tuohy, Christopher (committee member)

Skardal, Aleksander (committee member)

Goldstein, Aaron (committee member)

date

2020-08-28T08:35:17Z (accessioned)

2022-08-27T08:30:20Z (available)

2020 (issued)

degree

Biomedical Engineering (discipline)

embargo

2022-08-27 (terms)

identifier

http://hdl.handle.net/10339/96935 (uri)

language

en (iso)

publisher

Wake Forest University

type

Dissertation