Magnetic Optical Microarray Imager for Diagnosing Type of Diabetes in Clinical Matrices

Diabetes is a metabolic disorder in which body’s inability to produce enough insulin leads to either low (hypoglycemia) or elevated levels of glucose (hyperglycemia). This imbalance in glucose metabolism can eventually lead to serious health problems such as kidney failure, heart disease, blindness, etc. Insulin (a polypeptide hormone) serves as a valuable predictor in diagnosing the type of diabetes and depending upon its levels in clinical matrices, diabetes can be broadly classified as type 1 (< 50 pM) or type 2 (> 80 pM). In type 1 (insulin dependent), the body does not produce enough insulin, while in type 2 (non-insulin dependent), the excess insulin produced is not utilized by the body, thus elevating the glucose levels. 2012 statistics from American Diabetes Association reported 9.3 % of the population to be diabetic and a predicted 25% of population with pre-diabetic conditions. Diagnosis of diabetes, by ultrasensitive detection methods, has therefore become the need, which can detect and measure insulin levels at clinical sites.

We present herein, an ultrasensitive microarray imager, which can detect insulin levels in clinical matrices such as serum and whole blood by an optical tool, surface plasmon resonance. The imager involves an immunoassay utilizing antibody immobilized gold arrays and magnetic particles spiked various insulin concentrations to detect picomolar levels of insulin and diagnose the type of diabetes with high sensitivity. The magnetic microarray insulin imager developed is a promising platform for detecting insulin in serum and whole blood at clinical sites.

Acknowledgements. We are grateful for the financial support by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under Award Number R15DK103386.