The four-year project is based on technology previously developed by Houston Methodist nanomedicine faculty member Lidong Qin, Ph.D., who is the new project’s principal investigator. Qin’s “V-Chip,” or volumetric bar-chart chip, will be used to detect biomarkers for hepatocellular carcinoma (HCC), the most common cause of liver cancer. The device only requires a drop of blood from a finger prick.
The V-Chip allows the testing of up to 50 different molecules in a blood or urine sample. (Click thumbnail for larger version)
“Most of the burden of HCC is borne by people who have low income, with the highest incidence rates reported in regions of the world where infection with hepatitis B virus is endemic,” Qin said. “Developing an accurate and low-cost technology that assesses the risk of cancer could make a big difference to people who ordinarily can’t afford expensive tests.”
M.D. Anderson Department of Epidemiology Chair Xifeng Wu is the project’s co-principal investigator.
Qin and Wu will see whether the V-Chip accurately detects HCC biomarkers. The researchers will also determine which combination of these biomarkers proves most predictive of disease.
Among the biomarkers the researchers will look at are antigens of hepatitis viruses B and C, aflatoxin (a fungal toxin that at high doses is associated with cancer risk), and metabolic indicators of alcohol consumption, obesity, diabetes, and iron overdose.
Tests of the V-chip will not replace traditional testing methods, but rather be carried out in tandem so that patients’ care cannot be adversely affected.
Hepatocellular carcinoma is believed to be the third-highest cause of cancer death worldwide and the ninth leading cause of cancer death in the U.S. It is most commonly caused by a past infection of hepatitis viruses B or C (HBV or HCV) and cirrhosis of the liver caused by alcohol abuse or other toxic damage.
Qin’s V-Chip is composed of two thin, 3″ x 2″ slides of glass. In between the slides are wells for four things: (1) hydrogen peroxide, (2) up to 50 different antibodies to virtually any fat, protein, or sugar-based molecule, (3) blood serum or urine, and (4) a dye — any dye will do. Initially, the wells are kept separate from each other. A shift in the glass plates brings the wells into contact, creating a contiguous, zig-zagged space from one end of the V-chip to the other, mixing the four ingredients.
As molecules in the blood bind to antibodies bound to the glass slide, the enzyme catalase switches on and splits nearby hydrogen peroxide into water and oxygen gas. This approach is called ELISA, or enzyme-linked immunosorbent assay. The expanding oxygen pushes the dye up the column. The more of the drug there is, the more oxygen is created, and the farther the dye travels up the slide. Tests have shown the height of the dye is roughly proportional to the amount of substrate present, in this case, a hepatocellular carcinoma biomarker of interest. The end result is a visual bar chart that Qin says is easy to read and accurate.
Qin received another $2.1 million in July to develop the V-Chip for use in drug testing. That project is being funded by the National Institute on Drug Abuse, another division of the National Institutes of Health.
Qin is a Weill Cornell Medical College assistant professor of cell and developmental biology.
To speak with Lidong Qin, please contact David Bricker, Houston Methodist, at 832-627-2639 or [email protected].