Nanotechnology allows us to manipulate matter in new ways at the scale of atoms and molecules. In a new study, researchers show how they are using it to develop a drug delivery system that could precisely trigger drug release – for instance, only inside target cells.

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Four stages of transition from cylindrical parent nanoparticles to spherical daughter nanoparticles.
Image credit: Andrew Dove

The researchers describe their new “triggered-release” mechanism in the journal Nature Communications.

The mechanism starts with two “parent” nanoparticles, each carrying one half of the drug.

The parents are designed to interact only when they are near each other. When they interact, they create a “daughter” particle that releases the complete, active drug.

Andrew Dove, one of the senior investigators and a professor in the Department of Chemistry at the University of Warwick in the UK, says:

“We conceive that in the blood stream the particles would not be able to interact sufficiently to lead to release, only when they are taken into cells would the release be able to happen.”

“In this way,” he adds, “the drug can be targeted to only release where we want it to and therefore be more effective and reduce side effects.”

Another advantage of the mechanism is that it does not require an external stimulus to activate the interaction and release the drug.

Prof. Dove says the trick is getting the right chemical structure of the parent nanoparticles. While they are both made of cylinder-shaped polymer chains, they differ in the way their chemical bonds are directed within one part of their structure.

When the two parent nanoparticles are near enough to each other, the two polymer chains undergo a process called “stereocomplexation” that leads to a new “daughter” nanoparticle.

“In the process of this rearrangement, we propose that any molecules – such as drug molecules – that are encapsulated within the parent particles will be released,” Prof. Dove explains.

Prof. Dove says while they now plan to see how the triggered-release mechanism might be used to develop new cancer treatments, there is no reason why it could not also be used for a wide range of diseases.

Curiously, the daughter nanoparticles are not cylindrical like the parents, but spherical. The authors say this is because of a “stereocomplexation driving force that exists in this system changes the crystallization behavior of the core-forming blocks.”

In May 2014, Medical News Today reported how researchers could see a way to make purer, safer drugs using ‘twisted light’ and nanotechnology. They showed how exploiting the way tiny nanoscale structures uniquely twist light, it was possible to identify the undesirable – and potentially harmful – mirror image twin of a drug molecule.