A novel in vitro assay for peripheral nerve-related cell migration that preserves both extracellular matrix-derived molecular cues and nanofiber-derived topography

Background: Molecular composition and topography of the extracellular matrix (ECM) influence regenerative cell migration following peripheral nerve injury (PNI). Advanced tissue engineering strategies for the repair of neurotmesis-type PNI include the development of nanofiber-containing implantable scaffolds that mimic features of the ECM to orchestrate regenerative growth. Reliable and quantifiable in vitro assays are required to assess the ability of such substrates to influence migration of the cell types of interest. However, most popular migration assays monitor cell migration into a cell exclusion zone (CEZ) but have dubious abilities to preserve the molecular and topographical cues of the substrate. New method: Elastic band spacers (EBS), a simple, economical and standardized technique for the generation of well-defined CEZ based on the use of commercially available elastic bands, are introduced. Results: EBS could sufficiently preserve ECM-derived molecular and poly(epsilon-caprolactone) (PCL) nanofiberderived topographical cues. The application of EBS in the absence and presence of nanofiber-derived topographical cues was validated using perineurial cells and Schwann cells, both known to play key roles in peripheral nerve regeneration. Comparison with existing methods: In contrast to EBS, commercial silicone inserts and the popular scratch assay caused substantial ECM substrate disruption, thereby preventing these techniques from being included in further investigations employing deposition of PCL nanofibers and cell migration analysis. Conclusions: EBS represent a useful addition to the existing repertoire of migration assays offering significant benefits in terms of substrate preservation. The simplicity and economy of the approach make it immediately accessible to research groups at minimal extra expense.

Automated summary

The molecular composition and topography of the extracellular matrix play a crucial role in regenerative cell migration after peripheral nerve injury. A new technique called Elastic band spacers (EBS) has been introduced to preserve ECM-derived molecular and topographical cues while assessing cell migration. EBS represents a cost-effective and accessible tool for migration assays, providing significant benefits in terms of substrate preservation.