Chemists create reassembling nanofibres
4 Aug 2014
Researchers suggest their nanofibre breakthrough could lead to better methods for delivering drugs to the body.
A team of scientists from Carnegie Mellon University, US has developed a novel method for creating reassembling protein-polymer nanostructures that are similar to the fibres found in living cells, new research published in the journal Angewandte Chemie has found.
The researchers say the work offers promising insight into the fabrication of materials designed for drug delivery and tissue engineering applications.
“Where controlled polymerisation and organic chemistry meet biology, interesting things can happen
Prof Tomasz Kowelewski
Carnegie Mellon professor Tomasz Kowelewski said: “We have demonstrated that, by adding flexible linkers to protein molecules, we can form completely new types of aggregates. These aggregates can act as a structural material to which you can attach different payloads, such as drugs. In nature, this protein isn’t close to being a structural material.”
According to the researchers, the building blocks of the fibres are a few modified green fluorescent protein (GFP) molecules linked together using a process called ’click chemistry’.
Click chemistry, which originated initially in 1998, is a term applied to chemical synthesis as a means of quickly generating substances by joining small units together. It is not one single reaction, but describes a way of generating products that follows examples found in nature.
An ordinary GFP molecule does not normally bind with other GFP molecules to form fibres, the researchers suggest.
However, when research graduate Saadyah Averick modified the GFP molecules and attached PEO-dialkyne linkers to them, the GFP molecules appeared to self-assemble into long fibres.
Of vital importance is the fact these fibres disassembled after being exposed to sound waves, and then reassembled within a few days, the researchers said.
According to the researchers, this type of reversible fibrous self-assembly is highly sought after for use in applications such as tissue engineering, drug delivery, nanoreactors and imaging.
“This was purely curiosity-driven and serendipity-driven work,” Kowalewski said.
“But where controlled polymerisation and organic chemistry meet biology, interesting things can happen.”
To conduct its research, the US team utilised confocal light microscopy, confirming the nanofibre self-assembly using dynamic light scattering technology.
They also observed that the fibres were fluorescent, indicating that the GFP molecules retained their three dimensional structure while linked together.
“Our protein-polymer system gives us an atomically precise, very well-defined nanoscale building object onto which we can attach different handles in very precisely defined positions. It can be used in a way that wasn’t ever intended by biology,” Kowalewski said.
