Enzyme-Like Activity of Cerium Dioxide Colloidal Solutions Stabilized with L-Malic Acid

For the first time, stable aqueous colloidal solutions of cerium dioxide stabilized with L-malic acid have been obtained at ligand : CeO2 molar ratios of 0.2, 0.5, 1.0, and 2.0. Using dynamic light scattering, it has been shown that CeO2 sols are characterized by a narrow monomodal size distribution of aggregates, and the sols remain to be aggregatively stable in a Tris-HCl buffer solution. According to the chemiluminescence analysis of the enzyme-like activity of cerium dioxide sols with respect to hydrogen peroxide, the surface modification of the cerium dioxide particles with malic acid increases the enzyme-like activity of СеО2 up to 4.5 times.