Prooxidant potential of CeO2 nanoparticles towards hydrogen peroxide
Madina M. Sozarukova, Elena V. Proskurnina, В. К. Иванов
Abstract
The multifaceted enzyme-like activity of CeO 2 nanoparticles (CeNPs) expands the prospects for their potential biomedical applications. In this regard, there is a need for a comprehensive analysis of the redox behavior of CeO 2 nanoparticles in relation to key molecules of free radical homeostasis. Here, the prooxidant potential of CeNPs towards H 2 O 2 was investigated to elucidate both prooxidant capacity and prooxidant activity of CeNPs. To describe the kinetics in the luminol-H 2 O 2 system at pH 8.5 upon the addition of citrate-stabilized CeO 2 sol (3 nm), a numerical model of three reactions is proposed. The rate constants being a measure of prooxidant activity, were k 1 = 9.0 10 4 M -1 min -1 , k 2 = 2.0 10 -6 M -1 min -1 , k 3 = 2.9 10 -5 M -1 min -1 . The functionalization of CeO 2 nanoparticles surface with ammonium citrate increases their prooxidant capacity by two-fold, while modification with maltodextrin decreases it by six-fold. It was shown that the prooxidant capacity of citrate-stabilized CeO 2 sol in Tris-HCl is approximately four-fold higher than in phosphate buffer solution at pH 7.4.