Phosphate glass fibres and their role in neuronal polarization and axonal growth direction.

Phosphate glass fibres with composition 50P(2)O(5)-30CaO-9Na(2)O-3SiO(2)-3MgO-(5-x)K(2)O-xTiO(2)mol.% (x=0, 2.5, 5, respectively coded as TiPS(0), TiPS(2.5) and TiPS(5)) were drawn following the preform drawing approach. A 20-day solubility test in bi-distilled water was carried out on glass fibres with different compositions and diameters ranging between 25 and 82 μm. The results show that the glass composition, the initial fibre diameter and the thermal treatment are the main factors influencing the dissolution kinetics and that the fibres maintain their structural integrity and composition during dissolution. Biological tests were carried out on aligned TiPS(2.5) glass fibres using Neonatal Olfactory Bulb Ensheathing Cell Line (NOBEC) and Dorsal Root Ganglia (DRG) neurons. The fibres showed to be permissive substrates for cell adhesion and proliferation. The aligned configuration of the fibres seemed to provide a directional cue for growing axons of DRG neurons, which showed to sprout and grow long neurites along the fibre axis direction. These promising findings encourages further studies to evaluate the potential use of resorbable glass fibres (e.g.in combination with a nerve guidance tube) for the enhancement of the peripheral nerve healing with the role of supporting and guiding the cells involved in the nerve regeneration.