Facilitating diagnosis with a new type of biosensor

September 14, 2018, Ecole Polytechnique Federale de Lausanne
Facilitating diagnosis with a new type of biosensor
Credit: iStock

Scientists from the Max Planck Institute and EPFL have developed a new type of biosensor able to precisely quantify metabolites using a single drop of blood. The accuracy and simplicity of the procedure could make it a tool of choice for diagnosing and monitoring several diseases.

Diseases or injuries can result in dramatic changes in the levels of metabolites, which are chemical compounds produced by the body's metabolism. For example, an increase in the level of the amino acid in the blood is characteristic of the genetic disorder phenylketonuria (PKU). Phenylalanine levels in infants suffering from PKU need to be controlled through diet to avoid irreversible brain damage. It is therefore essential to be able to regularly monitor phenylalanine levels in the blood.

However, such monitoring currently requires blood samples to be sent to laboratories, and the results take several days to reach the patient. This delay often complicates disease management for PKU patients and their physicians. The treatment of numerous diseases could be improved if the blood concentration of disease-relevant metabolites were monitored at the point of care – ideally by the patient.

To address this problem, a team of scientists led by Professor Kai Johnsson of the Max Planck Institute for Medical Research (MPIMR) in Heidelberg and EPFL's Laboratory of Protein Engineering has developed a way to measure metabolite concentrations in small blood samples within minutes. The approach was validated with patients from the Heidelberg and Lausanne University Hospitals. The research was published today in Science.

Molecular engineering

"We introduce a fundamentally new mechanism to measure metabolites through blood analysis," says Qiuliyang Yu, the first author of the paper and a scientist at the Department of Chemical Biology at the MPIMR. "Instead of miniaturizing available technologies, we developed a new molecular tool." The tool is a light-emitting protein that changes color in the presence of the reduced cofactor nicotinamide adenine dinucleotide, known to biochemists by its acronym NADPH. This molecule can be produced in an enzyme-catalyzed reaction specific to the metabolite of interest, which means that the concentration can be determined by analyzing the color of the emitted light. Using different enzyme-catalyzed reactions, the same sensor can carry out quantitative assays of various metabolites, such as phenylalanine, glutamate and glucose.

Fast and accurate

In practice, the procedure is quite simple. In the case of phenylalanine, a drop of blood is taken from the patient through a painless finger prick. A fraction of the blood sample is then added to a reaction buffer and applied to paper containing the . When phenylalanine is consumed and NADPH is produced, the light emitted by the sensor changes color from blue to red – a change that can be detected by an everyday digital camera or smartphone. The change in color is then used to calculate the phenylalanine concentration.

The whole procedure takes only 10 to 15 minutes and can be done at the point of care. It is so easy and accurate that patients should eventually be able to test themselves, which is something the scientists are working on. "We are now looking for ways to further automate and simplify the test," concludes Qiuliyang Yu.

Explore further: Cheating on your diet? This blood test can tell

More information: Qiuliyang Yu et al. Semisynthetic sensor proteins enable metabolic assays at the point of care, Science (2018). DOI: 10.1126/science.aat7992

Related Stories

Cheating on your diet? This blood test can tell

September 4, 2018
By analyzing small molecules called metabolites in a blood sample, a scientist can determine if you're following your prescribed diet or cheating, researchers at the Johns Hopkins Bloomberg School of Public Health report.

Compounds found in green tea and wine may block formation of toxic metabolites

July 2, 2018
A new Tel Aviv University study suggests there is hope of treating certain inborn congenital metabolic diseases—a hope found in green tea and in red wine.

New treatment approved for rare disease PKU

May 25, 2018
(HealthDay)—Palynziq (pegvaliase-pqpz) has been approved by the U.S. Food and Drug Administration to treat phenylketonuria, commonly called PKU.

Are you sticking to your diet? Scientists may be able to tell from a blood sample

June 19, 2018
An analysis of small molecules called "metabolites" in a blood sample may be used to determine whether a person is following a prescribed diet, scientists at Johns Hopkins Bloomberg School of Public Health have shown.

Recommended for you

For-profit hospitals correlated with higher readmission rates

September 19, 2018
Patients who receive care in a for-profit hospital are more likely to be readmitted than those who receive care in nonprofit or public hospitals, according to a new study published by University of Illinois at Chicago researchers.

Nearly half of resident physicians report burnout

September 18, 2018
Resident physician burnout in the U.S. is widespread, with the highest rates concentrated in certain specialties, according to research from Mayo Clinic, OHSU and collaborators. The findings appear on Tuesday, Sept. 18, in ...

Separated entry and exit doors for calcium keep energy production smooth in the powerhouses of heart cells

September 18, 2018
Stress demands the heart to work harder and faster. To keep pace, the muscle must make its fuel at an accelerated rate. Bursts of calcium entering mitochondria—the cell's powerhouses—normally help control energy output, ...

Sugar content of most supermarket yogurts well above recommended threshold

September 18, 2018
A comprehensive survey of ingredients in yogurts highlights high sugar levels in many—particularly organic yogurts and those marketed towards children.

First gut bacteria may have lasting effect on ability to fight chronic diseases

September 18, 2018
New research showing that the first bacteria introduced into the gut have a lasting impact may one day allow science to adjust microbiomes—the one-of-a-kind microbial communities that live in our gastrointestinal tracts—to ...

A new defender for your sense of smell

September 18, 2018
New research from the Monell Center increases understanding of a mysterious sensory cell located in the olfactory epithelium, the patch of nasal tissue that contains odor-detecting olfactory receptor cells. The findings suggest ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.