Simultaneous enhancement in phosphorescence and its lifetime of PtOEP-peptide assembly triggered by protein interaction

We fabricated hybrid nanoparticles consisting of organic semiconducting material with peptide sequence to reflect the target protein interaction. A phosphorescent OLED material, platinum octaethylporphyrin (PtOEP) was self-assembled by reprecipitation with the A17 peptide (YCAYYSPRHKTTF) selected as a probe ligand in order to recognize heat shock protein 70 (HSP70). The phosphorescence intensity of the PtOEP-A17 assembly was enhanced by 125 % after treatment with HSP70. The specificity of the protein interaction was confirmed in both solution and solid states of the PtOEP-A17 assembly against to BSA and nucleolin. We figured out that the phosphorescence lifetime of PtOEP-A17 assembly after exposed to HSP70 increased significantly to 153 ns from initial 115 ns. These simultaneous enhancements in phosphorescence and lifetime triggered by the specific protein interaction would open new applications of PtOEP, a representative material of light-emitting device fields.