September 10, 2015

Science provides new way to peer into pores

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.”

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