Developing Catalytically Active Living Materials for Additive Manufacturing

Thesis (Ph.D.)--University of Washington, 2020Living materials are created through the embedding of live, whole cells into a matrix that can house and sustain the viability of the encapsulated cells. Through the cell immobilization process, their bioactivity (natural or engineered) can be harnessed for applications such as the production of high-value chemicals or biosensing environmental changes. While the idea of employing whole cell technologies is not new, the materials commonly employed in this space limit their implementation. Naturally derived polymeric materials often lack the robust mechanical properties needed for structural integrity of the materials, while many synthetic alternatives are either difficult to pattern or detrimentally influence cell viability and behavior. In this work, a novel platform of living materials is created, based on both commercially- available Pluronic F127 and a novel poly(alkyl glycidyl ether)-based triblock copolymer. The hydrogels that are afforded from these copolymers are stimuli-responsive, allowing for precise additive manufacturing of encapsulated cells into complex geometries. These stimuli responses include (1) a temperature response which allowed for facile processing of the material; (2) the shear response which facilitated the extrusion of the material through a nozzle; and (3) a UV-light induced polymerization which enabled the post-extrusion chemical crosslinking of network chains and the fabrication of robust printed objects. The mechanical properties of the living materials have been extensively characterized through the use of rheology. Additionally, the behavior of encapsulated cells has been explored through extensive microscopy of the living materials. The living materials developed herein have been demonstrated to effectively encapsulate yeast, bacteria, and algae while maintaining excellent cell viability for each microbial species. Through the use of extrusion 3D printing, precise spatial deposition of one or many cell types is made possible within a single printed construct. The printed living materials are shown to be effective to the on-demand and reusable production of high-value molecules, ranging from small molecules to peptides, through the use of both mono-culture or microbial consortia systems. Through the protection of embedded cells from preservation processes such as lyophilization, these Additively Manufactured Catalytically Active Living Materials (AMCALMs) can provide a platform for the sustainable generation of high-value compounds through repeated production phases