New molecule to track cancer drug in the body

The researchers at The Ohio State University in US created a luminescent molecule, called a peptide and made up of two amino acids. Then they hitched that light to the cancer medication so that it showed the chemo's arrival within cells.

"This is very important for personalised medicine. We really want to see what's going on when we give chemo drugs and this work paves the way for the exciting endeavour," said Mingjun Zhang, a biomedical engineering professor who led the study.

Biomedical engineers strive to find techniques that behave naturally within the body and leave without doing harm.

This research holds promise for doing just that because the peptide is one that should easily coexist with human cells and leave as harmlessly as it entered.

"You can combine your drug with this luminescent vehicle. Composed of natural amino acids, the nanoparticle is inherently biocompatible," said Zhang.

In the body or tissue of an animal or person, scientists would watch the fluorescent signal with an optical detection system, he said.

Researchers sandwiched their peptide to a common chemotherapy drug so that its light was hidden until the two elements peeled apart upon entering the cells.

Zhang was particularly delighted to see that the blue peptide, which can be seen under ultraviolet light, maintained its luminescence for extended periods of time.

Previous work to track drugs using organic dyes has been hampered by their tendency to fade with time.

"You can label it and you can attach it to a drug and see where the drug goes and when it is released," Zhang said.

It could give patients and their doctors information on how well and how quickly a medication is working for them.

"Maybe for some people a drug is taking effect in a few minutes and for somebody else it's hours and for somebody else it never takes effect," Zhang said.

The research team used doxorubicin, a widely used chemotherapy drug, for their lab work, but the discovery could apply to different types of treatments, they said.

A study was published in the journal Nature Nanotechnology.