The idea of the tracking system will be to help doctors and patients see how well and how quickly a chemotherapy drug is working.
In Nature Nanotechnology, researchers from Ohio State University (OSU) in Columbus describe how they developed and tested the new technique on cancer cells in the lab using a common cancer drug. Plans for animal testing are already under way.
The ability to track chemotherapy drugs at the cell level in real time - as it happens - in patients could revolutionize cancer care by helping doctors work out why two people may have different responses to the same treatment.
Senior author Mingjun Zhang, professor in biomedical engineering whose lab at OSU works on bio-inspired nanoparticles, says:
"This is very important for personalized medicine. We really want to see what's going on when we give chemo drugs and this work paves the way for the exciting endeavor."
Previous attempts to devise such a tracking system have failed because they used dyes that fade quickly and because they used toxic elements, says the team.
Fluorescent peptide 'is inherently biocompatible'
The holy grail of such research is to find materials that behave naturally in the body, exist easily alongside human cells, and leave without doing harm. The team believes they have nearly reached this goal because the material they are working on is a peptide.
The team created the tiny fluorescent peptide in Zhang's lab. The nanoparticle is made of natural amino acids and is inherently biocompatible, says Prof. Zhang, who adds that "our biological machines can easily take care of it."
The idea is that doctors will one day be able to watch the fluorescent signal sent out by the peptide attached to the chemotherapy drug with the help of an optical detection system.
Another feature of the peptide's design is that the researchers sandwiched it inside the chemotherapy drug so it does not light up until the two elements separate on entering cells.
Fluoresces for long periods
The researchers were pleased to see that that the blue peptide - which fluoresces under ultraviolet light - remains lit up for long periods. This has not been possible in experiments using organic dyes.
One example of how such a system could help doctors and patients is to see how well and how quickly a cancer drug is working.
In some people, chemotherapy can take effect in a few minutes, in others it can take hours, and there are also cases where it never takes effect, says Prof. Zhang.
The team tested the technique on doxorubicin, a widely used chemotherapy drug, but they say the fluorescent peptide method could apply to other medications, as Prof. Zhang explains:
"You can label it and you can attach it to a drug and see where the drug goes and when it is released."
Meanwhile, Medical News Today recently learned how a fluorescent probe could help surgeons remove all of a tumor the first time. The aim is to increase cases where 100% of the tumor is removed and thus reduce further operations and the chance the cancer will return, say researchers who tested the new probe at Duke University Medical Center.