A highly sensitive microsphere-based assay for early detection of Type I diabetes

A highly sensitive microsphere-based assay for early detection of Type I diabetes. Concept showing microsphere based detection of an Islet Cell Autoantibody (ICA) - Glutamic Acid Decarboxylase (GAD65) using Rolling Circle Amplification (RCA) on microspheres. Streptavidin-microspheres are conjugated with biotinylated-GAD65 followed by binding of GAD65Ab to microspheres. To these microspheres, biotin-GAD65 is added and coupled with bioyinylated DNA-primer via an avidin bridge. To the immobilized target primer, RCA circle is added followed by elongation using Phi 29 Polymerase and detection using SYBR Green II fluorescence.

A team of researchers from the Center for Engineering in Medicine at the Massachusetts General Hospital have developed a novel fluorescence-based assay for sensitive detection of antibodies within microliter volume serum samples. This new assay is at least 50 times more sensitive than the traditional radioimmunoassay (RIA), which is the gold standard currently used in the clinic.

This new technology is particularly attractive for immunological assays as it allows: 1) use of very small volumes of sample reagents (5 μL), and 2) use of traditional analytical systems such as a standard real time PCR requires much lower sample volumes than traditional ELISA methods allowing the modular bead-based assay to be modified for use in studies using small animal models, where the sample volume can be a limiting factor. The increased sensitivity of the assay could enable a more accurate determination of the onset of disease, as well as a better temporal resolution of disease progression. The report describing these results appears in the current issue of the journal Technology.

"This is a clever combination of the several existing techniques, the result of which is a more sensitive, non-radioactive, clinically-relevant assay," says Martin Yarmush, M.D., Ph.D., of the Massachusetts General Hospital and senior author on this paper. "It is our hope that this technique will become a useful tool for early detection of Islet Cell Autoantibodies (ICA) in at risk patients, which could lead to intervention before significant loss of islet cell mass".

"This method is partially built on the sensitivity of Rolling Circle Amplification (RCA), and we designed the assay to be modular so that it can be applied to any other antigen-antibody pair without the need for much modification. In the paper, we demonstrated superior detection capability of two different autoantibodies, but this is by no means the end of the story as the assay can be easily adapted to include as many autoantibodies as possible," says Shyam Sundhar Bale, Ph.D., the lead author on this paper. The team from the Massachusetts General Hospital plans to enhance this technology with a variety of engineering modifications, including multiplexing the assay for simultaneous detection of multiple antigens or antibodies within very small sample volumes.

More information: www.worldscientific.com/doi/ab… 42/S2339547814500174

add to favorites email to friend print save as pdf

Related Stories

New test detects toxic prions in blood

Jun 12, 2014

The first cases of Mad Cow disease in humans (properly called variant Creutzfeld Jakob Disease, or vCJD) occurred in the late 1990s and are thought to be the consequence of eating contaminated beef products. Since then, several ...

New microsphere-based methods for detecting HIV antibodies

May 23, 2013

Detection of HIV antibodies is used to diagnose HIV infection and monitor trials of experimental HIV/AIDS vaccines. New, more sensitive detection systems being developed use microspheres to capture HIV antibodies ...

Researchers find two new methods to determine ALK status

Jul 01, 2013

The implementation of personalized health care in cancer relies on the identification and characterization of cancer biomarkers and the availability of accurate detection systems and therapies for those biomarkers. Anaplastic ...

Recommended for you

Economic burden of prediabetes up 74 percent over five years

Nov 20, 2014

The economic burden of diabetes in America continues to climb, exceeding more than $322 billion in excess medical costs and lost productivity in 2012, or more than $1,000 for every American, according to a study being published ...

Gynoid fat resists metabolic risks of obesity

Nov 19, 2014

(HealthDay)—The differences in the developmental profiles of upper-body and lower-body fat depots may explain their opposing associations with obesity-related metabolic disease, according to research published ...

Treating diabetes one meal at a time

Nov 19, 2014

Recent estimates project that as many as one in three American adults will have diabetes in 2050. The American Diabetes Association observes November as American Diabetes Month, and this year's theme is America ...

User 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.