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Description
Barrier tissues in the body often form tubular structures that regulate molecular and water transport to maintain physiological function. We present a hierarchical biofabrication strategy to engineer such structures with tailored barrier properties, using ultrathin, wet-spun collagen membranes exhibiting high fibrillar alignment, compaction, and a Darcy permeability of 3.84 × 10⁻¹⁶ m². By stacking or rolling a defined number of membrane layers, followed by drying and genipin cross-linking, structures with tunable transport and mechanical properties are created. A case study demonstrates the design of a collagen-based tube mimicking the dimensions and permeability coefficient of the rat common bile duct. Ex vivo measurements showed a native bile duct permeability coefficient of 4.5 × 10⁻⁴ cm s-1 for sodium deoxycholate, a toxic bile acid. To match this while allowing for degradation over two weeks and a safety margin, we fabricated 30-layer collagen tubes (0.7 mm inner diameter, 0.05 mm wall thickness, 12 mm length), achieving up to 240 kPa burst pressure and 70 N mm-2 suture retention strength. The initial permeability coefficient was 0.27 × 10⁻⁴ cm s-1, with a Darcy permeability of 0.44×10⁻¹⁶ m², effectively limiting bile acid and water leakage. This approach offers a versatile platform for engineering extracellular matrix-based barriers for diverse biomedical applications.
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