Related Experiment Video
Updated: May 16, 2026

Photopatterning Proteins and Cells in Aqueous Environment Using TiO2 Photocatalysis
Published on: October 26, 2015
Mechanism for the enhanced peroxidation of linoleic acid by a titanium dioxide/hypochlorite system
Peter A C McPherson1, Peter M Boyle, Bryn T Türemen
1School of Applied Science, Belfast Metropolitan College, Belfast, UK. pmcpherson@belfastmet.ac.uk
Abstract:
Nanosized titanium dioxide (TiO₂) is a common component of sunscreen preparations and cosmetics as it reflects UV and visible light in accordance to Rayleigh's law. However, in aqueous environments, TiO₂ is an efficient photocatalyst, producing superoxide O₂⁻· and hydroxyl (HO·) radicals, which are highly damaging to biomolecules. We investigated the role of TiO₂ in promoting the peroxidation of linoleic acid (LA) alone and in the presence of hypochlorous acid (HOCl). TiO₂ significantly enhanced peroxidation of LA, which was further enhanced in the presence of HOCl. This latter finding involved the formation of singlet molecular oxygen in a Russell-type mechanism appearing to involve preformed lipid hydroperoxides (LOOH). In addition to lipid peroxidation, HOCl also mediated formation of 18:1 monochlorohydrins, which in the presence of TiO₂ appeared to decompose to kinetic products which supplemented peroxidation of linoleic acid. We present a theoretical mechanism which fits the available experimental data and may partially explain the dichotomy associated with HOCls role in lipid modification.
Related Concept Videos
Radical Autoxidation
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
Sharpless Epoxidation
Oxidation of Phenols to Quinones
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...

