Surface Modification of Nerve Guide Conduits with ECM Coatings and Investigating Their Impact on Schwann Cell Response

Abstract

In this study, layer-by-layer coatings composed of heparin and collagen are proposed as an extracellular mimetic environment on nerve guide conduits (NGC) to modulate the behavior of Schwann cells (hSCs). The authors evaluated the stability, degradation over time, and bioactivity of six bilayers of heparin/collagen layer-by-layer coatings, denoted as (HEP/COL)₆. The stability study reveals that (HEP/COL)₆ is stable after incubating the coatings in cell media for up to 21 days. The impact of (HEP/COL)₆ on hSCs viability, protein expression, and migration is evaluated. These assays show that hSCs cultured in (HEP/COL)₆ have enhanced protein expression and migration. This condition increases the expression of neurotrophic and immunomodulatory factors up to 1.5-fold compared to controls, and hSCs migrated 1.34 times faster than in the uncoated surfaces. Finally, (HEP/COL)₆ is also applied to a commercial collagen-based NGC, NeuraGen, and hSC viability and adhesion are studied after 6 days of culture. The morphology of NeuraGen is not altered by the presence of (HEP/COL)₆ and a nearly 170% increase of the cell viability is observed in the condition where NeuraGen is used with (HEP/COL)₆. Additionally, cell adhesion on the coated samples is successfully demonstrated. This work demonstrates the reparative enhancing potential of extracellular mimetic coatings.