Atomistic simulations of mechanically activated reactions for oxygen release from polymers†

Singlet oxygen molecules are useful in several therapeutic applications involving photo-activated release of oxygen from carrier molecules toward targeted cells. However, the drawbacks of existing photo-activated methods encourage the development of alternatives, particularly polymer mechanophores that act as oxygen carriers. Here, we present a reactive molecular dynamics simulation-based study of an endoperoxide-based polymer for which oxygen release can be activated either thermally or mechanochemically. Simulations of the polymers heated are compared to simulations of the polymers subject to compression and shear at room temperature. Results show that oxygen release is preceded by deformation of the anthracene ring in both thermal and mechanochemical reactions. However, in the mechanically activated reaction, this deformation is imposed directly by chemical bonding between the oxygen and atoms in the shearing surfaces, eliminating the need for high temperature to initiate the oxygen release. These results could be useful in the development of alternative therapeutic protocols that do not rely on photo-activated reactions.