Jennifer Knipe | 20-FS-001
Plant cell strains have been used to produce a range of pharmaceutical proteins, including antibodies, antigens for vaccines, growth hormone, cytokines, and therapeutic enzymes. Plant cells offer several advantages for producing countermeasures to chemical and biological threats. Thus, the ability to three-dimensionally (3D) print a plant cell bioink for use in a continuous flow-through bioreactor configuration could offer a modular, field-deployable production platform for these types of recombinant therapeutics. New bioreactor designs and geometries fabricated by 3D bioprinting plant cells may enhance mass transfer, control cell aggregation, and immobilize the cells for reuse over multiple production cycles, leading to a rapid and scalable process for biotherapeutic production.
The goal of this research was to demonstrate the feasibility of entrapping plant cells within a 3D-printable bioink while maintaining cell viability and activity to produce a therapeutic agent. We demonstrated that the hydrogel-encapsulated rice cells are at least 80 percent as viable as the cell in media control, and that these encapsulated cells remain viable for up to 14 days. We then demonstrated that the encapsulated cells not only remain viable but can also be effectively induced to produce the recombinant protein of interest—recombinant rice butyrylcholinesterase (rrBChE), a therapeutic protein capable of protecting against exposure to a broad range of organophosphate nerve agents (e.g. sarin)—on the same order of magnitude as the cells in media control. Furthermore, we developed a rice cell bioink with appropriate properties for extrusion-based printing methods. These findings will enable future work to optimize rrBChE production by 3D printing the cells, improve protein recovery from the hydrogel, and build a continuous flow-through bioreactor prototype.
Demonstrating the feasibility of a plant cell bioink is the first step on the path to creating 3D-printable bioreactors to advance rapid development of countermeasures to pathogens and emerging diseases. Thus, this study addresses the Laboratory's mission research challenge in chemical and biological countermeasures. In addition, this feasibility study builds upon the Laboratory's advanced materials and manufacturing core competency by furthering Livermore's multidisciplinary approach to developing innovative and tailored materials, structures, and advanced manufacturing methods. Moreover, this study addresses Livermore's bioscience and bioengineering core competency by exploring a novel bioreactor platform to rapidly engineer and produce biological therapeutics and products at multiple scales.
Publications, Presentations, and Patents
Varma, A. 2020. "Bioprinting Transgenic Plant Cells for Production of Recombinant Butyrylcholinesterase, a Bioscavenger." 31st Annual Undergraduate Research, Scholarship and Creative Activities Conference, University of California, Davis, CA, May 2020. LLNL-POST-818782