Ferritin-directed biomimetic photo-nanoreactors with directional cascade energy transfer for enhanced photocatalytic conversion.

HYPOTHESIS: Natural photosynthetic systems achieve highly efficient solar energy conversion through precisely organized light-harvesting networks and directional excitation energy transfer. Protein nanocage scaffolds are expected to spatially organize multiple chromophores to construct an artificial cascade energy-transfer system, thereby improving photon utilization and coupling light harvesting with photocatalytic conversion. EXPERIMENTS: A ferritin (Fn)-directed biomimetic photo-nanoreactor was constructed by integrating covalently conjugated eosin Y (EY) and electrostatically assembled carbon dots (CD1 and CD2) within a confined protein microenvironment. The hierarchical organization of these photoactive components enabled the formation of a sequential fluorescence resonance energy transfer (FRET) pathway from CD1 to CD2 and finally to EY. The structural characteristics, energy-transfer behaviors, and photocatalytic performance of the resulting CDs-EY@Fn nanoreactors were systematically investigated. FINDINGS: The Fn-confined nanoarchitecture established a directional two-step cascade FRET network with an energy-transfer efficiency of 61% and an antenna effect of 18.3, significantly enhancing spectral utilization and excitation-energy funneling. The optimized CDs-EY@Fn nanoreactor exhibited markedly improved photocatalytic conversion performance compared with free EY, achieving a product yield of 74.68% after irradiation, more than four times that obtained with EY alone. These findings demonstrate that protein-directed chromophore organization provides an effective strategy for constructing artificial photosynthetic nanoplatforms with integrated light harvesting and catalytic conversion capabilities.