Featured image: NTU Assoc Prof Pu Kanyi shining a UV light
at the nanoagents. Credit: NTU
Polymer nanoagents that can ‘light up’ tiny areas of
diseased tissues that conventional methods fail to detect, have been created by
a research team led by Nanyang Technological University, Singapore (NTU
Singapore).
The nanoagents, known as ‘semiconductor polymer
nanoparticles’ (SPNs), can store light energy from sources such as sunlight,
near-infrared light or even light from mobile phones, and then emit long-lasting
‘afterglow light’.
The research team from NTU Singapore tailored highly
sensitive SPNs to track down and lock on to diseased tissues in the body such
as cancerous cells, sending back near-infrared signals which can be received
and interpreted by standard imaging equipment.
Scientists and doctors now have more time to look at test
results, as the nanoagents continue self-illuminating and their light intensity
decreases by half only after six minutes.
Alternatively, if stored at -20 degrees Celsius, the sample
will maintain its results for a month, making it convenient for other
diagnostic experts to interpret and review the results at a later time.
When tested in mice, the method provided results 20 to 120
times more sensitive than current optical imaging methods and 10 times faster
in showing up diseased tissues.
Unlike conventional optical afterglow agents that are less
bright and contain rare-earth heavy-metal ions that are toxic to biological
cells, the new nanoagents are also organic, biodegradable and contain
biologically benign ingredients that are non-toxic.
The research was published in the scientific journal Nature
Biotechnology on October 16 2017. It could lead to future potential
applications in image-guided surgery and in monitoring the effects of drugs
that are seeking regulatory approval.
Associate Professor Pu Kanyi from NTU’s School of Chemical
and Biomedical Engineering, who led the research team, said, “The new polymer
nanoagents we have designed and built show a great deal of promise for clinical
applications. They can detect diseased tissue much faster than current optical
imaging techniques, and are much safer to use.
“We hope this may lead to technology that allows doctors to
diagnose and treat patients much earlier than is possible at present. Potential
use may be in image-guided surgery, where surgeons could use the technology to
help them precisely remove diseased tissues in real-time, and in monitoring the
effects of drugs that are seeking regulatory approval.”
Role in drug development
The technology can also be used to evaluate the behaviour
and therapeutic outcomes of drugs in the body, for example, whether drugs
induce liver damage as a side effect.
Drug-induced
liver damage is one of the most common reasons that the US Food and Drug
Administration withholds drug approval.
Evaluation of potential damage in advance of regulatory
approval is challenging because currently, studies performed in a controlled
environment outside of a living organism often have low predictive power of how
the drug reacts inside the organism.
Existing methods only track such activity at the tissue
level whereas the new technology works at a molecular level, monitoring increased
or decreased levels of biomarkers to determine how the drugs are working,
before their therapeutic action is complete, providing much greater predictive
power for drug development.
The study took two years and a patent is being filed for the
technology. The research team now intends to conduct further trials in larger
animal models.
The research team included researchers from the National
University of Singapore and the University of California San Diego.
