Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Diagnostics

Virus-based sensor detects bladder cancer markers in urine

Complex electrical measurements reveal concentrations of biomarkers and urine, improving accuracy

by Celia Henry Arnaud
December 21, 2021

 

Atomic force microscopy image of a virus-based biosensor with viruses (brown) embedded in a conducting polymer (blue).
Credit: Courtesy of Reginald Penner
A virus-based biosensor made of viruses (brown) embedded in a conducting polymer (blue) detects bladder cancer biomarkers in urine.

Researchers have made a virus-based biosensor that detects markers of bladder cancer in urine. Their goal is to make a dipstick that can quickly detect bladder cancer as part of routine urinalysis.

Reginald M. Penner, Gregory A. Weiss, and coworkers at the University of California, Irvine developed the sensor, which Penner described at Pacifichem, the International Chemical Congress of Pacific Basin Societies 2021, on Dec. 16.

The sensor has a layered structure. The top layer consists of viruses embedded in a conducting polymer. Under that is another layer of conducting polymer on top of a pair of electrodes. When biomarkers in urine bind to peptides displayed on the virus, the impedance between the electrodes changes. That impedance measurement contains information about the concentrations of both the biomarker and salts in the urine, enabling the researchers to detect picomolar biomarker concentrations.

Penner says this kind of sensor has advantages over sensors based on field-effect transistors, wherein the presence of a biomolecule of interest affects the flow of current through an electronic gate. Impedance signals, he says, contain more information. “It’s phenomenal how much the sensitivity improves.” The impedance sensor has a better signal-to-noise ratio, which enables shorter data acquisition times, higher precision, and better reproducibility among sensors. Achieving the full potential of the impedance requires the researchers to take measurements at multiple frequencies. The shift in the low frequency end of the spectrum reveals the concentration of the biomarker. Combining the low-frequency and high-frequency measurements allows them to calculate the salt concentration in the urine sample.

When a cancer biomarker binds, it causes a shift in the low-frequency end of the impedance spectrum that reveals the concentration of the biomarker. But they can also measure high-frequency impedance, which reveals the salt concentration of the urine. That measurement is important for knowing how dilute or concentrated the urine is. If someone is dehydrated, they may have a higher concentration of a biomarker that is not diagnostically relevant; if they are well hydrated, the biomarker might be more dilute. Penner told C&EN that factoring in the salt concentration helps determine this. “Now we can figure out what a certain concentration of a biomarker means,” he said.

“This is quite elegant work,” Bo Zhang, a biosensor expert at the University of Washington, wrote in an email, praising the sensor’s sensitivity. “I expect their sensor platform will be used for many other biosensing applications beyond what they have shown with bladder cancer.”

Penner and Weiss founded the startup PhageTech to commercialize the sensor technology. The company is currently conducting clinical trials of the biosensor for bladder cancer screening.

Advertisement

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.