Date of Graduation

5-2021

Document Type

Thesis

Degree Name

Master of Science in Biological Engineering (MS)

Degree Level

Graduate

Department

Biological and Agricultural Engineering

Advisor

Thomas Costello

Committee Member

Joshua Sakon

Keywords

wood species, surface roughness, tissue engineering, hardwood species, softwood species, wood pulp

Abstract

Cellulose is an abundant and naturally occurring biopolymer that has been used by humans for food, shelter, and clothing for about two centuries now. Highly crystalline nanoparticles derived from cellulose, called cellulose nanocrystals (CNCs), show great potential to meet the rising need for sustainable and nontoxic materials for biomedical applications. However, multiple biomedical applications of CNCs, such as those involving their use in tissue engineering scaffolds, require CNC-based structures to be stable in aqueous environments, a property that native CNCs do not possess due to their inherent hydrophilicity. Chemical crosslinking of CNCs addresses this issue by providing aqueous stability to CNC-based structures, by facilitating the formation of covalent linkages between cellulose molecules as well as strong intramolecular H bonding in the network. CNCs can be obtained from multiple sources such as cotton, wood, hemp etc. and properties of CNCs depend on the cellulosic source and process conditions used for extraction. However, how these source-based differences in properties impact the way CNCs crosslink with different crosslinking agents and the resulting properties of crosslinked CNCs is still unknown. This study focuses on evaluating the effect of wood source on the physicochemical properties of crosslinked CNCs. Key biomedical applications for which CNCs are a promising material are discussed and the physicochemical and mechanical properties of crosslinked CNCs that render them attractive for such applications are closely examined. The results via dynamic light scattering (DLS), zeta potential measurement, rheology, Fourier transform infrared spectroscopy (FT-IR), and atomic force microscopy (AFM), provide insight into how the wood source influences the physicochemical properties of crosslinked CNCs. The study also highlights the significance of these differences and the potential for tuning crosslinked CNCs’ material properties for particular applications.

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