Two-compartment microfluidic bioreactor with functionalized PEG hydrogels to promote platelet production in culture

Northwestern University, Evanston IL

Investigators

Abstract

1265029 - Miller Generating many units of 300-600 billion platelets from megakaryocytic cells in culture will require advances in hematopoietic (blood) stem and progenitor cell expansion, megakaryocyte production and maturation, and platelet release and recovery. Shear from blood flow in the sinuses is important for proplatelet and platelet release. Inspired by the bone marrow sinusoid niche, this project will employ a microbioreactor with two compartments separated by a porous support coated with microporous poly(ethylene glycol) hydrogel functionalized with adhesive ligands. To mimic proplatelet formation across the sinusoidal endothelium, megakaryocytes will be seeded on the hydrogel in the upper compartment and medium will be perfused through the lower compartment. The microbioreactor will be used to investigate effects of shear stress, hydrogel stiffness, and adhesive ligand types and density on proplatelet and platelet production. Increasing gradients of pH and chemokines will be investigated to further increase proplatelet formation. The perfusion system will allow platelets to be harvested as they are released, which is important because platelet quality deteriorates during storage at 20-24°C and even faster at 37°C. The quality of culture-derived platelets will be verified via agonist-induced activation. The microbioreactor could be scaled for clinical production of platelets using formats such as hollow-fiber bioreactors and spiral-wound membrane cartridges to generate the required surface area. Several million units of platelets are transfused each year in the United States and Europe. Production of platelets in culture by megakaryocytes derived from patient or matched blood stem cells would increase the supply and decrease the contamination risk and adverse immune responses, but platelet production in culture is currently very inefficient. Successful completion of the proposed research will bring the large-scale production of culture-derived platelets closer to fruition. Graduate students and undergraduates working on this project will be trained in an interdisciplinary environment. A key element of the project is for the graduate students to develop educational modules on microfluidics, polymer hydrogels, megakaryocytic cells, and platelets for high school students, including two half-day classes for the Oncofertility Saturday Academy and presentation at local high schools. The award from the Biotechnology, Biochemical, and Bioengineering Program of the CBET Division is co-sponsored by the Biomaterials Program of the Division of Materials Research.