Diabetes diagnosed with inexpensive, portable microchip test

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diabetes microchip

As childhood obesity rates rise, so do rates of type 2 diabetes in children. Coupled with the rise in type 1 diabetes in adults, it is becoming increasingly difficult to differentiate the two diseases without resorting to a slow, expensive lab test that takes days to check for antibodies unique to type 1. Now using nanotechnology on a microchip, researchers in the US have developed an inexpensive, rapid portable test that performs to lab standard.

Brian Feldman is one of the inventors of a microchip-based test for diagnosing type-1 diabetes.
Image credit: Norbert von der Groeben

Writing in Nature Medicine, researchers from Stanford University School of Medicine, CA, describe how the new handheld microchip test shows not only high sensitivity and specificity for the diagnosis of type 1 diabetes, but also potential to discover previously unknown biomarkers of the disease.

The researchers validated the microchip test using blood samples from newly diagnosed diabetes patients and people without diabetes. Both groups underwent the new test and the old lab-based test.

The team says the inexpensive portable test could not only improve patient care, but also help researchers better understand type 1 diabetes.

There are two main forms of diabetes mellitus – type 1 and type 2 – and while both are characterized by high blood-sugar levels, they have different causes and need different treatments.

Type 1 diabetes occurs when the immune system attacks the insulin-producing cells of the pancreas, effectively destroying the body’s ability to make the hormone that keeps blood sugar in check.

Type 2 diabetes occurs when the body develops resistance to insulin – so even though the pancreas can still produce the hormone, the cells that need it cannot use it properly.

The two forms can be distinguished by testing for the presence of the “auto-antibodies” that destroy the pancreatic cells – these will only be present in people with type 1 diabetes.

Increasing overlap in populations that can develop type 1 and type 2 diabetes

There was a time when children developed diabetes symptoms you could be fairly sure they had type 1 diabetes, and when middle-aged, overweight adults developed them, it was highly likely to be type 2.

The distinction was so sharp, lab confirmation was most often considered unnecessary, plus it was often avoided because the method was difficult and expensive.

But now, as childhood obesity rises, more children are developing type 2 diabetes, and for reasons that are unclear, more adults are developing type 1 diabetes, increasing the overlap between these previously distinct populations.

This has led to an increasing need for a more rapid, inexpensive way to differentiate the two diseases.

There is also a growing need for earlier diagnosis, as increasing evidence shows that early, aggressive treatment improves the outlook for patients with type 1 diabetes. Researchers believe if people with type 1 diabetes can be identified early enough, there is a good chance of stopping the immune system attacking the pancreas and preserving some capacity for insulin production.

Current type 1 diabetes test is lab-based, expensive and lengthy

The current radioimmunoassay lab method of diagnosing type 1 diabetes uses radioactive materials to detect the auto-antibodies and takes several days. Highly-trained staff are needed to carry out the test, which costs several hundred dollars per patient.

In contrast, the new microchip test uses no radioactivity, produces results in minutes, and requires minimal training to use it. As for cost, the researchers estimate each chip will cost around $20 to make, and can be used for at least 15 tests.

The new test also only needs a small amount of blood, as can be drawn from a prick of the finger, whereas the lab-based test needs a lab-based draw of blood.

The new test uses a “plasmonic gold chip for near-infrared fluorescence-enhanced detection” of the antibodies. The glass plates that form the base of the microchip are coated with an array of tiny, nanoparticle-sized gold islands. These islands amplify the fluorescent signal to allow detection of the auto-antibodies.

Senior author Brian Feldman, assistant professor of pediatric endocrinology at the School of Medicine, says:

“With the new test, not only do we anticipate being able to diagnose diabetes more efficiently and more broadly, we will also understand diabetes better – both the natural history and how new therapies impact the body.”

New test has potential as screening tool

He and his colleagues anticipate that the test has the potential to identify people at risk of developing type 1 diabetes, such as relatives of already diagnosed patients.

The test could be used to find auto-antibodies in at-risk people before they develop symptoms.

And also, because of its low cost, there is scope to explore its use for large-scale screening of the auto-antibodies in the general population, as Prof. Feldman explains:

“The auto-antibodies truly are a crystal ball. Even if you don’t have diabetes yet, if you have one auto-antibody linked to diabetes in your blood, you are at significant risk; with multiple auto-antibodies, it’s more than 90% risk.”

“There is great potential to capture people before they develop the disease, and prevent diabetes or prevent its complications by starting therapy early,” he adds, “But the old test was prohibitive for that type of thinking because it was so costly and time-consuming.”

The team has filed a patent application for the new test, and is in the process of launching a start-up company to get the test approved by the Food and Drug Administration and bring it to market, both in the US and globally.

Meanwhile, Medical News Today recently learned how researchers from the University of Cincinnati managed to reverse type 1 diabetes in mice. The treatment they used boosted the receptor TLR4 to repair a fault in immune cells. The receptor is also present in humans – with some differences – so more studies are needed to see if the treatment works in humans.

medicalnewstoday.

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