Advances in Microfluidic Technologies for Immunoassays and Biomarker Monitoring

Continuous, multiplexed, real-time measurements of biomarkers can unravel useful information about different health-related problems in patients. Conventional methods such as Enzyme-Linked Immunosorbent Assay (ELISA) and other types of immunoassays are well-established and widely used techniques in the lab and the clinic to measure different biomarkers. However, these methods fail to meet the mentioned criteria and cannot provide real-time and continuous data as they are time-consuming and include manual sample handling. Microfluidic technologies, with their unique features, can enhance these techniques to fulfill the outlined standards. In this work, we review the microfluidic platforms that enhance ELISA in different ways, and we investigate how they have transformed conventional methods into more reliable, rapid, automated, multiplexed, and continuous analytical methods. Specifically, we investigate how a multi-module microfluidic device, named Real-Time ELISA (RT-ELISA), has been used to continuously monitor the blood insulin and glucose levels from whole blood samples in a real-time and multiplexed manner. This platform has been characterized for its performance in vitro and in vivo monitoring of insulin and glucose and successfully shows the sub-minute change in the level of these biomarkers under complex physiological conditions, making it a potential tool in the management of patients with diabetes.