FRET pair printing of fluorescent proteins.

We report for the first time the directed assembly and characterization of FRET pairs on micrometer patterned surfaces. We used visible fluorescent proteins expressing a hexahistidine affinity tag as component molecules for the construction of the FRET constructs, where His(6)-EGFP served as donor fluorophore and His(6-)DsRed-FT as the acceptor. We created 2D and 3D structures that exhibit fluorescence resonance energy transfer at the interfaces between the donor and acceptor patterns in the lateral or axial directions, respectively. We quantitatively visualized the energy transfer by multiparameter optical microscopy.