Enhancement of optical properties of dyes for bioprobes by freezing effect of molecular motion using POSS-core dendrimers.

We demonstrate that the POSS-core dendrimer induced various kinds of favourable properties of trisvinyl-pyridinium triphenylamine (TP3PY) as a bioprobe. By using the amphiphilicity of the POSS core, the complexes of TP3PY with G2 POSS-core dendrimer were prepared, and the series of properties were investigated for the application as a bioprobe. Initially, it was shown that the adsorption of TP3PY onto the vessels was highly prohibited by the complex formation with the dendrimers. The solution states of the dendrimer complexes were maintained at least for 7 days. Moreover, it was found that the improvement of quantum yields and the elongation of fluorescent lifetimes were observed by the complexation with the dendrimers. Similar photochemical properties were obtained in a glassy state of 2-methyltetrahydrofuranat -196°C. The molecular rotations occurring at the excited state could be restricted by the complex formation with dendrimers. These characteristics induced by the complexation with the POSS-core dendrimer are of significance to improve the signal to noise ratio and the accuracy on the detection as a bioprobe.