Researchers at the University of Arizona have developed a new biological sensing method that can detect substances at an astonishingly minuscule amount. The method enables monitoring at zeptomolar level – a unit of measure 1000 times greater than the currently more familiar femtomolar unit.
This level of sensing, immediately applicable for drug testing and other research, has the potential to make new drug discoveries possible. Eventually, the advancement could lead to portable sensors that can detect environmental toxins or chemical weapons, monitor food quality, or screen for cancer.
A paper describing the results was published in the journal Nature Communications in late August.
Research on the project was led by Judith Su, associate professor of biomedical engineering and optical sciences, in collaboration with Stephen Liggett from the University of South Florida.
Using the FLOWER device, invented by Su, the team were able to pick up target compounds at zeptomolar concentrations, awithout the current need for labelling, which involves adding a fluorescent or radioactive tag to make a target compound stand out during testing.
Detecting a particular target compound in an environment – or seeing if it reacts with a particular protein – is tricky business. Su, principal investigator at the U of A Little Sensor Lab and a Craig M. Berge Faculty Fellow, said one of the current hurdles to biosensing is that, in the most prevalent technologies, the sensing compounds must be labelled.
FLOWER, an acronym for “frequency-locked optical whispering evanescent resonator,” is label-free. The sensing substances can be used in their native state to detect a target compound.
A major breakthrough
“In certain applications, it can be really difficult or impossible to put these tags on,” said Professor Su, “and they can increase cost. For things like small molecule drug screening, sometimes the tags can interfere with the results.”
The work is an exciting breakthrough, said Bruce Hay, a professor of biology at Caltech, who studies cellular biology and was not involved with the research. The new method’s label-free high sensitivity makes it immediately useful for advanced drug screening and other research, according to Hay.
“This represents a huge leap in our ability to probe the fundamental components and processes that make up biological systems,” he said.
Su and her collaborators at UCLA won a $650,000 Phase 1, National Science Foundation Convergence Accelerator grant last year to continue their investigations. Convergence Accelerator grants are awarded specifically to speed scientific research likely to produce beneficial applications for society.
“Dr. Su’s FLOWER sensor offers a quantum leap on peak sensitivity of label-free biosensing,” said Mario Romero-Ortega, head of the U of A Department of Biomedical Engineering. “This technology will allow a deeper understanding of membrane molecular events, enable early diagnostic assays and improve human health.”