Paper Microfluidic Based Device for Blood/Plasma Separation

Abstract

With the advent of research advances in the field of microfluidic devices, medical science is also progressing its way through fast and efficient micro-fabricated medical diagnostics. As most of the medical diagnosis involves blood test as the preliminary or necessary step, a smart micro-diagnostic for blood analysis can be considered as an essential. Blood being the most vital fluid, governing all the hemostatic and physiological conditions by acting as a carrier of all the essential minerals and vitamins throughout the body, makes it a potential analyte for diagnosis. But blood being a complex mixture of hematocrit, white blood cells and plasma along with other essential proteins, the analysis of the same is difficult. Especially, the presence of red blood cells (RBCs) and its agglutination causes interference in the procedure of analysis. For example the presence red blood cells can be a potential interfering factor during colorimetric detection of an analyte in the blood. Similarly, the presence of agglutination of RBCs and its count can interfere during a coagulation diagnosis. Thus, separation of plasma/serum from the erythrocytes is an essential step during a blood analysis. Conventionally, centrifugation and sedimentation were used to separate plasma/serum from the whole blood before its analysis. With the progressing microfluidic technology the micro-devices have been using numerous techniques like bifurcation (Zweifach-Fung effect), geometric obstructions, membrane filtration, and acoustic techniques for plasma separation. Thus, there exists several polymer based lab on chip biomedical micro devices performing the blood separation. Although these devices are portable, fast and efficient with small turnaround time, its fabrication procedure is mostly complex simultaneously involving integration of micro valves. It also requires a syringe pump or a voltage power supply for controlling the blood flow through its micro channels. Considering the complexity of the fabrication the paper based micro devices are steeply gaining its way through as a potential medium for micro diagnostics. Micro pads also doesn’t has requirement for any external driving source for guiding the fluid flow through. The porous nature of the same performs the capillary action, allowing passive fluid transport. Thus, the respective chapter emphasizes on the paper based micro-devices tailored by the researchers for blood plasma separation with a brief enunciation of their respective working mechanisms. It will also discuss the different fabrication methods intelligently employed by the porous media platform for efficiently performing the separation to further cater to the queries of future researchers in the respective area.