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

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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
Gillispie, Gregory James (author)
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)
2020 (issued)
degree
Biomedical Engineering (discipline)
2022-08-27 (liftdate)
embargo
2022-08-27 (terms)
identifier
http://hdl.handle.net/10339/96935 (uri)
language
en (iso)
publisher
Wake Forest University
title
The Underlying Mechanisms Governing Bioink Printability for Extrusion-based Bioprinting and Application to the Regeneration of Bone and Tooth Tissues
type
Dissertation

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