Highly efficient energy transfer from quantum dot to allophycocyanin in hybrid structures

•CdSe/ZnS QD transfers excitation energy to allophycocyanin fluorophores.•Allophycocyanin monomers show increased exciton–exciton interaction with QD.•We obtained covalently bound hybrid structures via random chemical coupling method.•Significant enhancement of APC fluorescence was shown in covalently bound hybrids.

Excitation energy transfer (EET) is observed in hybrid structures that composed of allophycocyanin and CdSe/ZnS core-shell quantum dot (QD). We demonstrate that the EET efficiency in such systems could be significantly increased under conditions inducing monomerization of allophycocyanin trimers. For these purposes, the EET efficiency was estimated under different experimental conditions (pH, high temperature or the presence of NaSCN) for self-assembled hybrid structures. Additionally, the hybrid structures were stabilized by covalent coupling which resulted in approximately 20-fold enhancement of allophycocyanin fluorescence upon excitation of QDs. The observed effect provides new opportunities for the practical implementation of hybrid systems as fluorescent markers.

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