Efforts to transfer intact mammalian chromosomes between cells have been attempted for more than 50 years with the consistent result being transfer of sub unit length pieces regardless of method. Inertial microfluidics is a new field that has shown much promise in addressing the fractionation of particles in the 2-20 μm size range (with unknown limits) and separations are based upon particles being carried by curving confined flows (within a spiral shaped, often rectangular flow chamber) and migrating to stable “equilibrium” positions of varying distance from a chamber wall depending on the balance of dean and lift forces. We fabricated spiral channels for inertial microfluidic separations using a standard soft lithography process. The concentration of chromosomes, small contaminant DNA and large cell debris in each outlets were evaluated using microscope (60X) and a flow cytometer. Using Dean Flow Fractionation, we were able to focus 4.5 times more chromosomes in outlet 2 compared to outlet 4 where most of the large debris is found. We recover 16% of the chromosomes in outlet #1- 50% in 2, 23% in 3 and 11% in 4. It should be noted that these estimates of recovery do not capture one piece of information- it actually may be that the chromosomes at each outlet are physically different and work needs to be done to verify this potential.
This paper describes a simple packaging method to fabricate microfluidic channels and obtain an optical detection interface for micro analysis systems. Specifically, this work reports on efforts to develop new methods for simple, fast and reliable design and fabrication of microscale field flow fractionation (FFF) based biological analysis systems. This modular detector interface results in a 38 nl detection region. Detector characterization is carried out to evaluate important figures of merit such as sensitivity, S/N ratio, and limit of detection. Plate height, a primary performance criterion for field flow fractionation is determined and compared with an on-chip detector. The developed system allow for a <i>plug-and-play</i> approach to the optical interface has resulted in flexibility in operation and increased robustness of the micro device.