Abstract: Cells may be grown in a bioreactor, and the cells may be activated by an activator (e.g., a soluble activator complex). Nutrient and gas exchange capabilities of a closed, automated cell expansion system may allow cells to be seeded at reduced cell seeding densities, for example. Parameters of the cell growth environment may be manipulated to load the cells into a particular position in the bioreactor for the efficient exchange of nutrients and gases. System parameters may be adjusted to shear any cell colonies that may form during the expansion phase. Metabolic concentrations may be controlled to improve cell growth and viability. Cell residence in the bioreactor may be controlled. In embodiments, the cells may include T cells. The cells may include T cell subpopulations, including regulatory T cells (Tregs), for example.

Abstract: A method for functionalizing a hollow-fiber membrane for cell expansion of targeted cells (e.g., natural killer cells) includes contacting a biotinylating molecule to a surface of the hollow-fiber membrane including an extracellular matrix component, the biotinylating molecule binding to the extracellular matrix component and having an affinity for the targeted cells. The biotinylated molecule may be selected from the group consisting of: cytokine, epitope, ligand, monoclonal antibody, stains, aptamer, and combinations thereof. The extracellular matrix component may be selected from the group consisting of: fibronectin, vitronectin, fibrinogen, collagen, laminin, and combinations thereof.