Fabrication and Optimization of a Polycaprolactone-Based Ductular Blood-Brain Barrier Model Using an Electrospinning Technique

Abstract

Central nervous system (CNS) disorders are the primary cause of the global health burden. Nevertheless, novel therapies approved for these disorders are among the fewest compared with their counterparts. The absence of effective, reliable in vitro blood-brain barrier (BBB) models that mimic in vivo barrier properties hinders the discovery of therapies for CNS diseases. This work introduces a three-dimensional (3D) system that uses a polycaprolactone (PCL) ductular scaffold to most closely mimic the structure of blood-brain capillaries. The duct was prepared via electrospinning, optimized, and characterized for fiber structure and mechanical strength. Furthermore, the designed duct was seeded with endothelial cells (ECV-304) to assess their ability to proliferate and grow within the ductal fiber. Finally, barrier integrity was evaluated by an immunofluorescence assay and transepithelial/transendothelial electrical resistance (TEER) measurements. The optimized duct displayed Beadles’ fiber with a high Young’s modulus value (34.7 ± 3.59 MPa), reflecting its good mechanical strength. Besides, ECVs-304 could cover 85.36 ± 14.36% of the duct surface after 14 days of seeding. The results showed that seeding the duct with a high cell density (20 × 106 cells/mL) facilitated more rapid cell coverage and reduced time without affecting cell viability. Additionally, ZO-1 expression was significantly higher and formed a relatively larger network compared to the 2D membrane. The duct prepared with 25% w/v PCL and a 1-h electrospinning duration exhibited significantly higher TEER values on days 7 (115.92 ± 31.1 Ω/cm2) and 14 (186.33 ± 52.75 Ω/cm2) compared to the 2D controls. Henceforth, this biomimetic model is expected to provide valuable insights into BBB dynamics, its involvement in disorders, and implications for drug delivery.