Researchers develop new tests to detect nutritional deficiencies in harsh environments


Mothers and children in communities with scarce resources may appear to be well fed but often suffer from micronutrient deficiencies. Now NIBIB-funded researchers have developed a system that can be used for tests to quickly identify blood micronutrient levels such as iron, iodine, folic acid and zinc in remote areas with limited health infrastructure.

Micronutrient deficiencies can cause stunted growth, anemia, neurological disorders and death. According to the Centers for Disease Control and Prevention, two billion people worldwide suffer from these shortcomings and about 2.6 million children under the age of five die each year.1

Accurate identification of populations with low levels of these vital micronutrients requires a blood test. Unfortunately, the people most affected by this problem live in underserved communities in developing countries with few doctors or medical facilities. Tests under these conditions must be economical, accurate, easy to use by people with minimal training and able to withstand shipping to remote areas without refrigeration. These are known as point-of-care technologies, which give results in an hour or less so that individuals who may have traveled miles to be tested get results quickly and can potentially start treatment immediately if needed.

The development of these tests is the passion of Mark Styczynski, Ph.D., associate professor at the School of Chemical and Biomolecular Engineering and his colleagues at Georgia Tech, with additional collaborators at Northwestern University in Illinois.

The test is based on two proteins produced by genes found in bacteria. The researchers inserted the two necessary genes on small DNA rings called plasmids. While there are individual genes taken from the bacteria in the test, there are no bacterial cells, so it is a "cell-free" system. This is important because a cell-free system can be freeze-dried for storage and then reconstituted when tested in remote areas in the field.

Adds David Rampulla, Ph.D., director of the NIBIB program in synthetic biology for technological development,

The creation of this cell-free system depended on the team's ability to produce bacterial proteins without the need for bacteria. This is an excellent example of a growing field known as synthetic biology, which harnesses the power of biological systems to create new types of medical diagnoses and treatments. "

Bacterial genes produce proteins whose activity is influenced by the amount of zinc in the blood drop. More zinc increases the activity of proteins, causing a color change. The color can vary from yellow when little or no zinc is present, to brown or red when zinc is medium, to purple with high levels.

A critical aspect of the test developed by Styczynski and colleagues was overcoming a problem consistent with this type of color change test. The blood contains hundreds of different proteins and other molecules. This mix of components differs from person to person and can significantly change the degree of color change in the reaction.

The team developed a calibration system that took into account the specific changes caused by the unique combination of components in the blood of each individual patient. Their complex chemical calibration method led to accurate readings despite variations in each patient's blood chemistry.

Styczynski states: "although the test provides a simple visual color change, making it so simple has involved many sophisticated analyzes that have led us to the exact mix of components that make the test work in low-resource environments where it is desperately needed" .

The group is working with interested business partners to make the test widely available, says Styczynski. A mobile phone app is also being developed that would compile the test results and could lead to a database for epidemiological investigations to allocate regional resources for the treatment of micronutrient deficiency.



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