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Abstract: TH-PO0033

Bioinspired Polycaprolactone Mats Electrospun on Silicon Nanopore Membranes for Kidney Tissue Engineering Applications

Session Information

Category: Bioengineering

  • 400 Bioengineering

Authors

  • Torres, Alonso, University of California San Francisco, San Francisco, California, United States
  • Bajaj, Ruchika M, University of California San Francisco, San Francisco, California, United States
  • Brakeman, Paul R., University of California San Francisco, San Francisco, California, United States
  • Fissell, William Henry, Vanderbilt University, Nashville, Tennessee, United States
  • Roy, Shuvo, University of California San Francisco, San Francisco, California, United States
Background

Renal replacement therapy should replicate the functions of the kidney nephron. Silicon nanopore membranes (SNM) are robust blood filters that support encapsulation of renal proximal tubular epithelial cells (RPTEC). In this study, electrospun polycaprolactone (PCL) mats on SNM were characterized by physical properties and ability to support renal cell growth on SNM.

Methods

Pellets of PCL (5% w/v) were dissolved in acetone and nanofibers were electrically deposited onto foil or SNM with a 2.1cm2 surface area. The mixture dispensing rate was 6 mL/hour using a Spingenix SG100 electrospinner system. Fabrication parameters included adjustments to the gap between the needle and plate; collagens I and IV were also incorporated. Scanning electron microscopy, surface water contact angle (WCA) measurements, uniaxial tensile testing, and three-day LLC-PK1 cell viability were assessed. Cells were seeded at a density of 500,000 cells/cm2 and relative mRNA levels of LRP2, CYP27B1, NHE3, and GAPDH were measured via qRT-PCR. Chemical barrier performance with inulin was determined with 3-D printed flow cells with apical and basal compartment ports.

Results

Mats consisted of PCL nanofibers with average diameters of 400 nm and arranged to create rhombus pore-shaped dimensions of <1 um. Mat thicknesses were comparable to commercial transwell membranes (~10um). Collagen-enhanced mats exhibited improved hydrophilicity (<90° WCA). The Young’s moduli of the mats were at least 10-fold less than the transwell controls. LLC-PK1 cells on PCL mats with collagen IV exhibited upregulation of NHE3 and CYP27B1, by over 50- and 2-fold, respectively compared to control wells. After two days of culture, the cells exhibited 80% viability and the chemical barrier integrity was at least 90% intact.

Conclusion

PCL Mats were successfully electrospun onto SNM with thin nanofibers intercalated with collagen to form pores and surfaces conducive to RPTEC growth and function. Mats fabricated with collagen IV presented the best combination of surface properties, cell viability, and up regulation of key genes expressed predominantly within RPTEC compared to control wells. Future work will focus on further development toward emulating the renal tubular basement membrane architecture and investigating solute transport characteristics.

Funding

  • Private Foundation Support

Digital Object Identifier (DOI)