Microfluidic lab-on-a-chip (LOC) device for point-of-care (POC) diagnostics have been widely developed for the rapid detection of infectious diseases such as HIV, TB and Malaria. Blood plasma separation is an initial step for most blood-based diagnostics. Although, centrifuge method is the classical bench-top technique, it is time and labor intensive, and therefore, automation and integration of blood plasma separation in the LOC device is ideal for POC diagnostics. Here, we propose a novel microfluidic blood plasma separation device for POC diagnostics. A membrane filter for filtration was positioned on top of a vertical up-flow channel (filter-in-top configuration) to reduce clogging of red blood cells (RBCs) by gravity-assisted cells sedimentation to prevent hemolysis of RBCs. As a result, separated plasma volume was increased about 4-fold (2.4 µL plasma after 20 min with human blood) and hemoglobin concentration in separated plasma was decreased about 90 % due to the prevention of RBCs hemolysis in comparison to a filter-in-bottom configuration. On-chip plasma contains ~90 % of protein and ~100 % of nucleic acids compared to off-chip centrifuged plasma, showing comparable target molecules recovery. This investigation will lead to a simple and reliable blood plasma separation device that can be utilized by individuals with minimal training in resource-limited environments for POC diagnostics.
Project end date: 07/27/17