Measurement of glycated hemoglobin levels using an integrated microfluidic system

Diabetes mellitus (DM) is a common non-communicable disease worldwide. Since DM may lead to serious complications, its treatment and care relies on early diagnosis leading to strict glycemic control monitored by the periodic measurement of the patients’ blood glucose levels. However, glucose levels can easily fluctuate due to diet, exercise, insulin resistance, stress, and other factors. Alternatively, the percentage of glycated hemoglobin (HbA1c) in the blood reflects an average glucose concentration over the past 2–3 months with fewer variations due to non-glycemic factors. Therefore, the accurate measurement of the HbA1c in the blood provides a more effective route to diagnose and to monitor DM than a conventional blood glucose measurement. For the measurement of HbA1c, immunoassays have become a widely used method. Therefore, to demonstrate automatic HbA1c measurement, we have developed a microfluidic system to perform a chemiluminescence immunoassay on a single chip automatically except the treatment of samples was undertaken off-chip and required centrifugation. Compared to routine clinical protocols, which rely on bulky benchtop instruments, the developed system is more compact in size (3.8-cm wide and 6.8-cm long) and consumes less samples (volume = 1 μL) and reagents (volume = 150 μL). It is also less labor-intensive to perform an immunoassay using this chip. With further refinements in assay development, this device may be a promising replacement for conventional HbA1c measurement in the near future.