Aggregation of chlorophyll a induced in self-assembled membranes composed of DMPC and DHPC

Abstract The J-aggregate of chlorophyll a (Chl a ) functions as a light-harvesting antenna in natural systems. In this study, we employed the phospholipid membranes composed of longer-chain 1,2-dimyristoyl- sn -glycero-3-phosphocholine (DMPC) and shorter-chain 1,2-dihexanoyl- sn -glycero-3-phosphocholine (DHPC), as a platform to induce Chl a aggregates. The DMPC/DHPC assembly at the mixing ratio ( q ) = 1.5 induced J-aggregates of Chl a at 20 °C with a total lipid concentration of 20 mM. While, Chl a aggregates were not observed in the membranes at q  = ∞ (DMPC vesicles) and q  = 0 (DHPC micelles). The surroundings Chl a molecules in DMPC/DHPC at q  = 1.5 were estimated to comprise a less polar environment, based on the deconvolution analysis of Soret band spectrum (400–440 nm). The photo-reduction activity of Chl a J-aggregates was investigated in lower lipid concentration conditions.