The paths
fluorescent particles take as they diffuse through a porous nanoscale
structure reveal
the arrangement of the pores through a technique developed by
scientists at Rice
University. (Credit: Landes Research Group/Rice University)
Rice University lab finds technique to characterize
nanoscale spaces in porous materials
(September 10, 2015) Rice
University scientists led a project to “see” and measure the space in porous
materials, even if that space is too small or fragile for traditional
microscopes.
The Rice lab of chemist Christy Landes invented a technique
to characterize such nanoscale spaces, an important advance toward her group’s
ongoing project to efficiently separate “proteins of interest” for drug
manufacture. It should also benefit the analysis of porous materials of all
kinds, like liquid crystals, hydrogels, polymers and even biological substances
like cytosol, the compartmentalized fluids in cells.
The research with collaborators at the University of
California, Los Angeles (UCLA) and Kansas State University appears in the
American Chemical Society journal ACS Nano.
It’s easy to use a fluorescent chemical compound to tag, or
“label,” a material and take a picture of it, Landes said. “But what if the
thing you want a picture of is mostly nothing? That’s the problem we had to
solve to understand what was going on in the separation material.”
The team aims to improve protein separation in a process
called chromatography, in which solutions flow through porous material in a
column. Because different materials travel at different speeds, the components
separate and can be purified.
“We learned that in agarose, a porous material used to
separate proteins, the clustering of charges is very important,” Landes said.
While the protein project succeeded, “when we matched experimental data to our
theory, there was something additional contributing to the separation that we
couldn’t explain.”
The answer appeared to be with how charged particles like
nanoscale ligands arranged themselves in the pores. “It was the only possible
explanation,” Landes said. “So we needed a way to image the pores.”