Design and Computational Modeling of Spiral Microfluidic Channel for Sorting and Separating the Biomolecules

Background: Microfluidic technologies are a very challenging area today in the field of biomolecule analysis. This has become feasible with the today’s advanced technologies by designing and fabricating the microfluidic channel. Materials and Methods: Initially, microfluidic channels are used to separate large molecules, where the molecular dimension of the fluidic filter is greater than the gap size. In this work, separation of biomolecules (like RBC, WBC and platelets) that are smaller than the microfluidic filter gap size is demonstrated. Results and Discussion: Due to the curvilinear nature of the spiral, there exists two vortices called dean vortices within the channel and this is influenced by dean flow, centrifugal flow and tubular pinch effect. While flowing a small aliquot of blood in the channel, due to these three effects, molecules attain equilibrium position at one point. The position of equilibrium will be different for different sized biomolecules and this varies with different input velocities. Conclusion: The obtained computational modeling results show how the equilibrium positions influence the separation efficiency of biomolecules in passive based microfluidic filter. Compared with the traditional random nanoporous materials such as gel or polymer monolith, spiral based microfluidic channels can be made precisely to have a pre-determined loop count and Dean Flow number (De).