Fluorescence correlation spectroscopy to study diffusion through diatom nanopores.

The intricate pore architecture of diatom frustules has been extensively studied mainly as the basis of diatom classification. There have, however, been very few reports on understanding the effect of the pore architecture on the movement of molecules through the pores. Information on molecular transport though diatom membrane pores has the potential to help develop more efficient membrane filtration systems. In this paper the transport of molecules through individual diatom nanopores is investigated. Fluorescence correlation spectroscopy (FCS) is used to determine diffusion coefficients. Thus, for the very first time, we measure the effect of the three dimensional pore structure of the diatom Coscinodiscus wailesii, on the mean diffusion coefficient through the pores. The results show almost a 50% decrease in the diffusion coefficient relative to that in the free solution.