Mimicking a Light‐Harvesting Complex to Accelerate Photooxidation in Asymmetric Lipid Membrane Nanoreactors

Abstract

ABSTRACT In nature, photosynthesis is driven by solar light and a large proportion of the visible spectrum is absorbed by the light harvesting complexes (LHCs), which then transfer the energy to the reaction center. Inspired by nature, we implemented a light harvesting energy transfer cascade within biomimetic lipid bilayers of liposomes built with DPPC (1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine), using membrane‐anchored fluorescein, 2‐(3,6‐dihydroxy‐9H‐xanthen‐9‐yl)‐5‐dodecanamidobenzoic acid (FlC 12 ) as primary absorber and membrane anchored eosin Y, hexadecyl 2‐(2,4,5,7‐tetrabromo‐3,6‐dihydroxy‐9H‐xanthen‐9‐yl)benzoate (EYC 16 ), as energy acceptor to sensitize oxygen and generate the reactive oxygen species 1 O 2 . Finally, the model substrate nicotinamide adenine dinucleotide (NADH) is oxidized by 1 O 2 within the compartmentalizing liposome nanoreactors. It was observed that our metal‐free LHC system has only a minor effect on the photooxidation rate of NADH when the nanoreactor membrane is functionalized symmetrically. By contrast, asymmetric membrane functionalization of the liposome nanoreactor membranes leads to acceleration by 16% to 27% when using multi‐colored light emitting diodes (LED) or simulated solar light, respectively.