1) Biocompatibility / Non-Toxicity
2) Formation of Stable Fibers
3) Guided Neuronal Growth
Re 1): The magnetic nanoparticles and other components that constitute the Fibermag formulation and the application of a magnetic field have been tested in cell culture with neuronal cells as well as with rat dorsal root ganglion (DRG) explants. No toxic or other negative effect on cell or DRG viability was observed.
Re 2): Fiber formation in vitro is reliably achieved under conditions that generate long (> 1mm) fiberguides in either 2D (surface) or 3D (matrix in space). After crosslinking and removal of the temporary magnetic field, the formed fiberguides persist over weeks in 3D in a stabilizing matrix and indefinitely on a surface (2D).
Re 3): Magnetic nanoparticles, the resulting fiberguides, neuronal cells and regrowing axons and neurites are readily visible in brightfield and fluorescence microscopy with 20x, 40x and higher objectives. We observe guided neuronal growth in 2D, with some axonal extensions growing over 0.5 mm and perfectly parallel to the magnetic fiberguides. We are now optimizing the Fibermag process for use in 3D in vivo. The resulting formulation and protocol will then be tested in animal experiments.