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

Abstract

In this study, we investigated surface modification through the layer‐by‐layer method as a straightforward and highly stable approach for depositing layers of natural polymers onto a commercial nerve guide conduit (NGC), thereby mimicking the extracellular matrix. The application of NGCs for nerve regeneration is constrained by the size of the lesion, limiting their use to small gaps (1‐2 cm). The principal aim of this modification is to augment the cellular response specific to peripheral nerve injury (PNI) repair processes and enhance the overall performance of NGCs. To achieve this objective, we conducted in vitro studies examining the stability, degradation over time, and bioactivity of six bilayers of heparin/collagen layer‐by‐layer coatings, denoted as (HEP/COL)6, after incubating the coatings with cell culture medium prior to cell seeding. The stability study revealed that (HEP/COL)6 is stable after incubating the coatings in cell media for up to 21 days. We evaluated the impact of (HEP/COL)6 on human Schwann cells (hSCs), focusing on viability, protein expression, and cell migration. The presence or absence of the nerve growth factor (NGF) was considered during all the experiments. These assays showed that hSCs cultured in (HEP/COL)6 had enhanced protein expression and migration. This condition increased 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 was also applied to a commercial collagen‐based NGC, NeuraGen®, and hSC viability and adhesion were studied after six 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 was observed in the condition where NeuraGen® was used with (HEP/COL)6. Additionally, we successfully demonstrated cell adhesion on the coated samples.This article is protected by copyright. All rights reserved