In vitro Blood–Brain barrier model based on recombinant spider silk protein nanomembranes for evaluation of transcytosis capability of biomolecules

The blood–brain barrier (BBB) limits the uptake of central nervous system (CNS)-targeting drugs into the brain. Engineering molecular shuttles for active transportation across the barrier has thus potential for improving the efficacy of such drugs. In vitro assessment of potential transcytosis capability for engineered shuttle proteins facilitates ranking and the selection of promising candidates during development. Herein, the development of an assay based on brain endothelial cells cultured on permeable recombinant silk nanomembranes for screening of transcytosis capability of biomolecules is described. The silk nanomembranes supported growth of brain endothelial cells to form confluent monolayers with relevant cell morphology, and induced expression of tight-junction proteins. Evaluation of the assay using an established BBB shuttle antibody showed transcytosis over the membranes with an apparent permeability that significantly differed from the isotype control antibody. •Recombinant spider silk nanomembranes support the growth of brain endothelial cells.•Silk membranes are only 1 μm thick with ECM like structure and good protein permeability.•Brain endothelial cells cultivated on silk nanomembranes can be used as a simple BBB model.•The in vitro blood–brain barrier model showed higher transcytosis for an antibody brain shuttle compared to control.