Surfactant Semiconductors as Trojan Horses in Cell-Membranes for On-Demand and Spatial Regulation of Oxidative Stress

Oxidative stress is a cause for numerous diseases and aging processes. Thus, researchers are keen to tune the level of intracellular stress and to learn from that. An unusual approach is presented here. The methodology involves multifunctional surfactants. Although their molecular design is nonbiological—a fullerenol head group attached covalently to pi-conjugated dyes—the surfactants possess superior biocompatibility. Using an intrinsic fluorescence signal as a probe, it is shown that the amphiphiles become incorporated into the Caco-2 cells. There, they are able to exhibit additional functions. The compound reduces cellular stress in dark reaction pathways. The antagonistic property is activated under irradiation, the photocatalytic production of reactive oxygen species (ROS), resulting in cell damage. The feature is activated even by near-infrared light (NIR-light) via a two-photon process. The properties as molecular semiconductors lead to a trojan horse situation and allows the programming of the spatial distribution of cytotoxicity.