Figure 4.

In vivo versus in vitro: an overview of different culture approaches for generating platelets and erythrocytes. In vivo cell maturation occurs in a complex environment in which cells experience different mechanical and biochemical cues due to cell-to-cell and cell-to matrix interactions. In the classical in vitro two-dimensional culture, cell contacts, confinement and environmental biomechanics are lost; moreover cells in contact with the plastic are artificially polarized. In the threedimensional culture, topography and stiffness can be modeled to mimic the native environment. Only cell cultured in flow conditions can recapitulate blood hydrodynamics. Microfluidic devices have the ability to enable extension of proplatelets and the release of functional platelets. Three-dimensional bioreactors combine the advantages of a three-dimensional environment with flow through the scaffold: mature cells can migrate toward the perfused compartment to release either mature erythrocytes or platelets. Cell culture in agitated or stirred-tank bioreactors has been exploited to allow large-scale production of platelets or erythrocytes. 2D: twodimensional; 3D: three-dimensional. The figure was created using Servier Medical Art templates licensed under a Creative Commons Attribution 3.0 Unported License (https://smart.servier.com).