Background

Human renal proximal tubular epithelial cells (RPTECs) are widely used as in vitro models for studying kidney biology and supporting the development of new therapeutics. However, conventional porous culture membranes, such as polycarbonate Transwells, do not accurately reproduce the structural and biochemical properties of the native basement membrane. As a result, renal epithelial cells often fail to fully differentiate and function, limiting the physiological relevance of these in vitro models.

Biolaminin® contribution

To create a more biomimetic culture environment, Meyer et al. evaluated Biosilk 521, a recombinant spider silk membrane coated with Biolaminin 521 to better mimic the native kidney basement membrane. The researchers investigated whether recreating key structural and biochemical features of the extracellular matrix could improve the differentiation and function of human renal epithelial cells compared with conventional porous membranes.

Renal epithelial cells cultured on Biosilk 521 adopted a morphology that more closely resembled native renal epithelium. Compared with conventional culture membranes, the cells displayed a more cuboidal morphology, deposited their own extracellular matrix, and exhibited reduced cellular stress. While barrier integrity was maintained under both culture conditions, Biosilk 521 also supported enhanced epithelial differentiation, accompanied by increased expression of clinically relevant renal transporters and restoration of directional anion and cation transport.

In addition to promoting epithelial differentiation, Biosilk 521 revealed an unexpected advantage over conventional culture substrates. Polycarbonate membranes released detectable bisphenol A (BPA), activating estrogen-mediated signaling pathways, whereas no detectable bisphenols were released from the protein-based spider silk membranes.

Future outlook

Developing physiologically relevant in vitro tissue models depends on recreating the native cellular microenvironment. In this study, Biosilk 521 provided a biomimetic basement membrane environment that supported renal epithelial differentiation while preserving important physiological functions, thereby creating a more physiologically relevant in vitro kidney model. The authors highlight this approach as a promising strategy for developing more predictive kidney models to support drug discovery and disease research.

Cited study: Meyer A et al. Recombinant spider silk membranes promote human renal epithelial differentiation and function. Biofabrication 18, 025001 (2026). https://doi.org/10.1088/1758-5090/ae3eb9

Product used in this study:

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  Biosilk 521

  3D culture substrate

  Biosilk 521 is a recombinant 3D culture matrix biofunctionalized with Biolaminin 521 to create stem cell relevant niches for pluripotent (PSC) and […]
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