Added a reference paper for iMatrix-221.

Added a reference paper for iMatrix-221.
Aoki, H., Yamashita, M., Hashita, T., Iwao, T., &amp Matsunaga, T. (2020). Laminin 221 fragment is suitable for the differentiation of human induced pluripotent stem cells into brain microvascular endothelial-like cells with robust barrier integrity.
Fluids and Barriers of the CNS, 17(1):25, 1-11, 2020.
Pabmed ID: 32228708


Background: In vitro blood–brain barrier (BBB) models using human induced pluripotent stem (iPS) cell-derived brain microvascular endothelial-like cells (iBMELCs) have been developed to predict the BBB permeability of drug candidates. For the diferentiation of iBMELCs, Matrigel, which is a gelatinous protein mixture, is often used as a coating substrate. However, the components of Matrigel can vary among lots, as it is obtained from mouse sarcoma cells with the use of special technics and also contains various basement membranes. Therefore, fully defned substrates as substitutes for Matrigel are needed for a stable supply of iBMELCs with less variation among lots.