[1] It provides a straightforward way to scale up culture systems for industrial production of cell or protein-based therapies, or for research purposes.
[2][3] These solid or porous spherical matrices range anywhere between 100-300 um in diameter to allow sufficient surface area while retaining enough cell adhesion and support, and their density is minimally above that of water (1 g/ml) so that they remain in suspension in a stirred tank.
[2][3] The advantages of microcarrier technology in the biotech industry include (a) ease of scale-up, (b) ability to precisely control cell growth conditions in sophisticated, computer-controlled bioreactors, (c) an overall reduction in the floor space and incubator volume required for a given-sized manufacturing operation, (d) a drastic reduction in technician labor, and (e) a more natural environment for cell culture that promotes differentiation.
Early in microcarrier development history, synthetic materials were overwhelmingly used, as they allowed for easy control of mechanical properties and reproducible results for the evaluation of their performance.
[4] Therefore, extra precaution must be taken on determining the stir speed and mechanism, so that the resulting fluid dynamic forces are not strong enough to adversely affect culture.
[4][3] The development of porous microcarriers greatly expanded the capabilities of this technology as it further increased the number of cells that the material can hold, but more importantly, it shielded those within the particle from external forces.
[4] Microcarriers of the same material can differ in their porosity, specific gravity, optical properties, presence of animal components, and surface chemistries.
[2] Two-dimensional culture also suffers from poor diffusivity of nutrients and gases, requiring added media and supplements to be manually evenly distributed, and may result in irreproducible data.
[1] Parameters such as pH, oxygen pressure, and media supplement concentrations can be continually monitored within a bioreactor as opposed to manually testing small samples from plates.
[3] Hepatocytes, chondrocytes, fibroblasts and more have been successfully delivered using biocompatible microcarriers to in vivo targets for the repair of damaged tissues.