A Bead-Based Quantum Dot Immunoassay Integrated with Multi-Module Microfluidics Enables Real-Time Multiplexed Detection of Blood Insulin and Glucagon.

Analyzing diabetes-related hormones such as insulin and glucagon using conventional enzyme-linked immunosorbent assay (ELISA) has been the gold standard. However, ELISAs have a long sample processing time, including blood serum/plasma preparation which restricts the number of measurement time points, making it difficult to accurately track hormone dynamics in relation to each other and to blood glucose levels. Here, a multi-module microfluidic platform, named quantum dot integrated real-time (QIRT)-ELISA system, that uses a bead-based quantum dot-mediated immunoassay (BQI) to continuously monitor insulin and glucagon in whole blood samples and in a multiplexed setting is demonstrated. The use of BQI simplifies the technical aspect of the system, removes the need for bulky and expensive equipment, and most importantly enhances the sensitivity, specificity, and temporal resolution. Validation experiments measuring levels of insulin and glucagon in rats during glucose tolerance tests demonstrate the accuracy of QIRT-ELISA for simultaneously measuring endogenous hormones within the physiological range during an oral glucose load.