Sticky molecules attract select clientele

Chemists at North Carolina State University have created an uneven layer of ‘sticky’ nanoparticles that they say will lead to improvements in a wide range of processes and devices.

Researchers at North Carolina State University have created an uneven layer of nanoparticles that will lead to improvements in a wide range of processes and devices.

This uneven coating – nanoparticles of gold in a layer that change from very dense to very sparse across a surface of selected molecules – is said to have chemical engineers and physicists taking note.

‘This material promises to be the first in a series with many applications in electronics, chemistry and the life sciences,’ said Rajendra Bhat, a doctoral student at North Carolina State University.

What Bhat and his mentor – Dr. Jan Genzer, assistant professor of chemical engineering at NC State -have created is a surface coated with ‘sticky’ molecules in a decreasing density.

A kind of molecular template, this adhesive surface can be modified to attract different kinds of particles for different applications, all of them arranged in useful gradients.

According to Genzer, the ability to vary and control the concentration of captured particles allows chemists and other scientists to devise sensors, filters, DNA-screening processes and, potentially, single-electron capacitors and transistors.

Some components of fluids, for example, could pass through the gaps in the less-concentrated part of the gradient, but be blocked by the thicker concentration. Such filters could also be designed to detect or capture harmful viruses or toxins.

The controlled distribution of particles is also said to allow rapid testing of potential catalysts – always in demand by chemical, pharmaceutical and petroleum industries – because numerous substances and variations in their amounts can be tested simultaneously.

Genzer and Bhat initially attached gold nanoparticles to their sticky molecular template because gold is conductive, biocompatible and well understood. But experiments with other particles, bonded to other kinds of surfaces, are under way.

The NC State chemical engineers admit they haven’t thought of all the possibilities. ‘There are many more applications,’ added Bhat, ‘and we are open for collaboration.’

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