Numerical modeling and experimental validation of uniform microchamber filling in centrifugal microfluidics

In this paper, a comprehensive approach to numerical and experimental analysis of microchamber filling in centrifugal microfluidics is presented. In the development of micro total analysis systems, it is often necessary to achieve complete, uniform filling of relatively large microchambers, such as those needed for nucleic acid amplification or detection. With centrifugal devices, these large microchambers must often be orientated perpendicularly to the direction of centrifugal force and are usually bounded by materials with varying surface properties. The resulting fluidic flow in such systems can be complex and is not well characterized. To gain further insight into complex fluidic behavior on centrifugal microfluidic platforms, numerical modeling using the Volume of Fluids method is performed to simulate microchamber filling in a centrifugal microfluidic device with integrated sample preparation, amplification, and detection capabilities. Parametric analyses are performed using numerical models to predict microchamber filling behavior for a range of pressure conditions. High-speed flow visualization techniques are used to track the liquid meniscus during filling of the microchambers, and comparison to the numerical predictions for experimental validation is achieved by analyzing the liquid volume fraction as a function of the non-dimensional temporal profile during filling. When channel filling profiles are compared, the numerical model predictions utilizing static conditions are in strong agreement with the experimental data. When dynamic modeling conditions are used, the numerical predictions are extremely accurate as compared to the experimental data.