Energy Transfer on Cytoskeleton of Red Blood Cell Ghosts and their Efficiency Control by KCl Concentration-induced Cell Shrinkage.

Lipid bilayer membranes such as liposomes have been utilized as platforms for bioinspired artificial photosynthesis. Embedding functional compounds, including chromophores and catalysts, into two-dimensional lipid membranes allows their high local concentration and proximity, resulting in enhanced reactivity compared to that of homogeneous solutions. The control of photoreactions by the physical and chemical properties of membranes, such as fluidity and phase separation, has also been well studied in recent years. In contrast, it remains difficult to control chemical reactions via dynamic membrane deformation. Here, we report on the control of excitation energy transfer using red blood cell ghosts (RBCGs) as scaffolds, relying on their asymmetric lipid membranes and inherent and unique deformability. RBCGs, in which donor and acceptor molecules were chemically conjugated to a two-dimensional cytoskeleton located beneath the inner membrane, exhibited energy transfer, and their efficiency varied depending on the amount and ratio of donor and acceptor modifications, as confirmed by experimental and theoretical analysis. Furthermore, the KCl concentration-induced RBCG shrinkage enhanced the energy transfer efficiency. Our proposed method is expected to facilitate the construction of photoreaction systems that can be controlled via membrane deformation.