Zeta potential of alumina powders with different crystalline phases in simulated body fluids

► δ-Al2O3, γ-Al2O3 and θ-Al2O3 were prepared by heat treatment of boehmite. ► δ-Al2O3, γ-Al2O3 and θ-Al2O3, did not form apatite in 1.5SBF over a period of 7 days. ► δ-Al2O3 gave a negative zeta potential in an acidic simulated body fluid.