Inspired by the human placenta: a novel 3D bioprinted membrane system to create barrier models

Abstract

Barrier organ models need a scaffold structure to create a two compartment culture. Technical filter membranes used most often as scaffolds may impact cell behaviour and present a barrier themselves, ultimately limiting transferability of test results. In this work we present an alternative for technical filter membrane systems: a 3D bioprinted biological membrane in 24 well format. The biological membrane, based on extracellular matrix (ECM), is highly permeable and presents a natural 3D environment for cell culture. Inspired by the human placenta we established a coculture of a trophoblast-derived cell line (BeWo b30), together with primary placental fibroblasts within the biological membrane (simulating villous stroma) and primary human placental endothelial cells—representing three cellular components of the human placental villus. All cell types maintained their cell type specific marker expression after two weeks of coculture on the biological membrane. In permeability assays the trophoblast layer developed a barrier on the biological membrane, which was even more pronounced when cocultured with fibroblasts. In this work we present a filter membrane free scaffold, we characterize its properties and assess its suitability for cell culture and barrier models. Further we show a novel placenta inspired model in a complex bioprinted coculture. In the absence of an artificial filter membrane, we demonstrate barrier architecture and functionality.

Modelling the Human Placental Interface In Vitro—A Review

“…Moreover, TEER values were higher when BeWo trophoblasts were cultured on the membrane containing fibroblasts rather than in monotypic cultures, demonstrating a reduction in permeability (reduced leakiness) due to the incorporation of the stromal compartment. [26]). (c) A transwell model with a layer of trophoblasts cultured on top of vasculature in a 3D gel matrix.…”

“…This model was employed to examine cell damage signaling across the barrier by exposing rat embryonic cortical neurons to conditioned medium collected from the in vitro placental barriers assembled with direct or indirect contact with the vascular bed. Although the vessels were not perfused, [26]). (c) A transwell model with a layer of trophoblasts cultured on top of vasculature in a 3D gel matrix.…”

“…However, by focusing on just one aspect of the placenta (trophoblasts), these models lack physiological complexity and a comparable cellular microenvironment. Recently, Kreuder et al addressed some of these drawbacks by including essential components of the placental villi, such as fibroblasts and endothelial cells [ 26 ], as represented in Figure 2 b. Their model involved bioprinting a methacrylated gelatin membrane (GelMA), which mimics extracellular matrix (ECM) features, containing primary placental fibroblasts, to simulate villous stroma.…”

“…Their model involved bioprinting a methacrylated gelatin membrane (GelMA), which mimics extracellular matrix (ECM) features, containing primary placental fibroblasts, to simulate villous stroma. BeWo trophoblasts and primary human placental endothelial cells were cultured on either side of this printed membrane, thus representing a more complex model of human placental villi [ 26 ]. Barrier properties were assessed by two permeability assays: one using a fluorescently labeled molecule to measure solute flux, and the other by impedance-based measurements using a transepithelial electrical resistance (TEER) system.…”

The Role of the 3Rs for Understanding and Modeling the Human Placenta

“…While the results of these studies are highly promising and useful for investigating placental structure and function, the use of Matrigel and gels such as fibrin [ 70 ] or gelatin methacrylate [ 71 ] as scaffold materials poses some challenges. As they are derived from animals, they not only pose ethical concerns but also possess a high degree of batch-to-batch variability.…”