Date of Award

Summer 8-16-2024

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Advisor

Bashir Khoda

Second Committee Member

Justin Lapp

Third Committee Member

Vincent Caccese

Abstract

Emerging as a beacon of promise, green bioprinting pioneers the fusion of 3D bioprinting technology with the intricate organization of plant cells, particularly microalgae, within engineered tissues. The optimization of this process at an industrial scale hinge upon understanding the post-bioprinting cell growth density variation within hybrid hydrogel biomaterial scaffolds.

This study delves into the convergence of biotechnology and micro-biofabrication, employing a phototropic approach to unravel the behavior of microalgae-based bioinks sequel to their subjection to microextrusion forces during 3D bioprinting. Three hydrogel biomaterials—Alginic acid sodium salt (ALGINATE), Nanofibrillated Cellulose (NFC) – TEMPO, and CarboxyMethyl Cellulose (CMC)—are strategically chosen for their scaffolding capabilities. The investigation unfolds in two folds: the development of bioinks from individual or hybrid hydrogel compositions, and the subsequent analysis of their impact on cell proliferation and morphology. The growth dynamics of Chlorella microalgae cells within these varied hydrogel compositions are meticulously probed using periodic absorbance measurements. Additionally, the study examines the shear thinning properties of the hydrogel compositions through viscosity and shear stress assessments. Notably, NFC demonstrates a reduced shear thinning capacity compared to CMC, as evidenced by viscosity data obtained across various shear strain rates. The results, quantified through absorbance values, unveil intriguing patterns. Mono-hydrogel substrates with pronounced adhesive characteristics tend to curtail Chlorella cell proliferation, while Alginate, with comparatively lower adhesion, appears to foster an increase in cell concentration alongside a slight increase in viscosity.

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