Direct Visualization of
Dye and Oligonucleotide Diffusion
in Silica Filaments with Collinear Mesopores
- Publication date
- Publisher
Abstract
The diffusion dynamics of terrylene diimide (TDI) dye
molecules
and dye-labeled double-strand DNA were studied in micrometer long
silica filaments containing collinear, oriented mesopores using single
molecule fluorescence microscopy. TDI was used as a stable and hydrophobic
probe molecule for single molecule structural analysis. We used template-free
mesoporous silica filaments with 4 nm pore diameter and chemical functionalization
with one or two types of trialkoxysilane groups to enhance the affinity
between the host system and the guest molecules. Insights about the
mesoporous structure as well as the translational and orientational
diffusion dynamics of the guest molecules observed along micrometer
long trajectories could be obtained. Additionally, the stability of
DNA oligomers (15 base pairs, bp, about 5.3 nm long) within the mesopores
was examined, showing no degradation of the oligonucleotide upon incorporation
into the mesopores. Diffusion of both guest molecules could be controlled
by exposure to vapors of water or chloroform; the latter both induced
a reversible on–off control of the translational movement of
the molecules