Image: A small domino-sized cartridge holds the membrane for the newly developed low-cost field test for liver cancer screening (Photo courtesy of the University of Utah College of Engineering).
Researchers have developed a highly portable, low-cost immunoassay technology that enables low limits of detection (LoD) by combining solid-phase microextraction membranes, gold nanoparticle labels, and surface-enhanced Raman scattering. Their prototype device successfully measured a liver cancer biomarker at LoD within only ~2 minutes. The team is also working to lower the cost to ~ USD 3 per test. The assay can likely be easily modified to detect infectious diseases such as tuberculosis, malaria, and dengue fever.
Currently, testing for liver cancer involves lab-based blood tests and ultrasound imaging, both of which require traveling to major cities and can often cost more than a month’s salary in low- and middle-income countries.
The research team, led Prof. Marc Porter and surgeon and Prof. Courtney Scaife of University of Utah (Salt Lake City, UT, USA), developed a test for hepatocellular carcinoma that doesn’t involve sending a specimen to a blood lab and cuts the wait time for results from 2 weeks to 2 minutes. This inexpensive test can be administered wherever the patient is, which would be particularly valuable in developing nations with little access to hospitals.
The new test measures alpha-fetoprotein (a widely-used marker used to screen individuals for hepatocellular carcinoma) directly from human serum at an estimated LoD of 3 pg/mL. The device uses a small domino-sized plastic cartridge containing a paper membrane that selectively traps protein biomarkers from biological fluids. A small droplet of blood, saliva, or urine, or even a teardrop, from the patient is dropped onto the membrane. This is followed by the droplet of gold nanoparticles, which tags the biomarkers trapped in the membrane. If the biomarkers are present, a red spot appears, signaling the patient has the disease and should seek additional testing and possible treatment.
“The concept is similar to a home pregnancy test, but instead of flowing laterally, it flows through the membrane,” said paper first-author Jennifer Granger, research associate at U. Utah. The idea for the test is a spinoff of a similar test Prof. Porter developed years ago that astronauts on the International Space Station used to test the cleanliness of their drinking water. “This is a smarter offshoot of that,” said Prof. Porter.
Now that the team has proven the concept with liver cancer and built a prototype test kit, researchers plan to evaluate the technology in Mongolia in spring of 2019. The East Asian country has the highest rate of liver cancer in the world.
A handheld spectrometer manufactured by project collaborator B&W Tek (Newark, DE, USA) can analyze the membranes and measure the amounts of biomarkers present, which in the future could help determine disease severity or monitor how a patient is responding to treatment.
Utah-based nutritional supplement company USANA is interested in using a form of the test for customers with certain vitamin deficiencies. “USANA has a keen interest in the ability to measure certain vitamins and biomarkers in various bodily fluids that can be related to a person’s health status,” said Mark Brown, executive director of Laboratory Sciences at USANA, “Rather than taking a blood sample and sending it off to lab for analysis, this technology could make it possible for people to do their own analysis in the comfort of their own home. Small sample size and simplicity of use are crucial components of making this a reality, and this research is a step closer to that end.”
The study, by Granger JH et al, was published August 9, 2017, in the journal of Analytical Methods.
University of Utah