Enhanced photoluminescence by tyrosine-containing bolaamphiphile self-assembly.

Photoluminescent spherical nanostructures were prepared through the self-assembly of a tyrosine-containing bolaamphiphilic molecule, and their antenna effect was examined. The photoluminescent spherical nanostructures were simply prepared by self-assembly of bolaamphiphile molecules in an aqueous solution in which water-soluble photosensitizers and lanthanide ions were dissolved. The photosensitizers and lanthanide cations were incorporated with the phenol group and the carboxyl end of the tyrosine moiety, respectively. Through fluorescence microscopy and photoluminescence spectroscopy analyses, the various combinations of two lanthanide ions (Eu and Tb) and four photosensitizers were screened for synergetic photoluminescence with bolaamphiphile self-assembly. The bolaamphiphile assembly enhanced the photoluminescence intensity by a factor of around 2 when it was associated with Tb and salicylic acid. This enhancement is driven by the phosphorescence enhancement of the photosensitizer induced by the π-π interactions with the phenol group in tyrosine. These results indicate that the tyrosine-containing bolaamphiphile is a promising molecule that can easily produce a soft nanoscaled host matrix with an antenna effect for photoluminescence.