Engineering peripheral nerve devices with patterned magnets

The clinical treatment of nerve injury usually needs surgical intervention to repair tissue that has been severed. Problems arise when the resulting nerve ends cannot be sewn back together because the injury 'removes' a section of nerve, forming a gap. Nerve has the ability to re-grow and in such instances an entubulation conduit can be used to guide new nerve growth across a gap injury site. This approach is limited but can be made more effective by implanting nerve support cells (Schwann cells) inside the conduit. However, the implanted support cells have no spatial organisation to guide regenerating nerve filaments. We therefore plan a pilot study to build a device that can control the position of Schwann cells with micrometer accuracy using nanobeads and parallel magnetic field elements. If successful, we will scale up our approach to developing a magnetic conduit for non-invasively controlling the position of Schwann cells with accurate alignment inside a conduit for improving nerve repair strategies.

The clinical treatment of peripheral small nerve injury gaps usually involves direct end-to-end suturing if the two nerve ends can be aligned without tension. However, this approach is not appropriate for longer gap injuries, as tension in the nerve cable is known to inhibit regeneration. This has led investigators to develop bioengineered nerves, which concentrate predominantly on the use of guidance channels. The behaviour of cells to accurately align is an important parameter for engineering peripheral nerve, and accurately aligning Schwann cells is expected to direct axonal re-growth more effectively than current guidance approaches. The use of magnetic micro/nanobeads has seen a dramatic increase in biological and clinical applications recently. We will therefore fabricate a device that combines a field-controlled patterned ferromagnetic array for cell trapping within a bioreactor for growing peripheral nerve Schwann cells. The device will also allow non-invasive imaging by confocal microscopy for analysis. The main body of work will concern aligning Schwann cells in 2D culture, providing an exit point for making a 3D bioreactor magnetic array device if successful.