Neural cell growth on TiO2 anatase nanostructured surfaces

Titanium oxides have anti-inflammatory activity and tunable electrochemical properties that make them attractive materials for biomedical applications. This work investigated the compatibility of nanometric coatings of low-temperature phases of TiO₂ with neurons in 4-day and 10-day cultures, using different cell densities to quantify cell survival and neurite extension. TiO₂ films were prepared by sol–gel and thermal treatment (250–450 °C) of hydrolyzed titanium tetra-isopropoxide on electrically conducting or insulating slides. The conducting substrates were not passivated by the nanometric oxide layer and could be used as electrodes. Characterization of the films showed nano-structured TiO₂ containing exclusively Ti⁺⁴ valence in anatase and amorphous phases. When coated with polylysine, all films permitted good neuron attachment and survival for at least ten days in culture. However, they generally reduced neurite growth compared to cell culture borosilicate glass, with dendrites more affected than axons. The analyses of surface topography, hydrophilicity, charge and chemical composition revealed that TiO₂ chemistry was the main factor responsible for neurite inhibition.