Separation of proteins and DNA by microstructure-changed microfuidic free flow electrophoresis chips

Microfuidic free-flow electrophoresis (μFFE) is a micro-separation analysis technology with continuity, no solid support medium and mild separation conditions. However, the bubble problem has limited its application for a long time. Here, we proposed a μFFE device that isolated the bubbles from the separation chamber with partitioning bars of ∼40 μm wide in ∼5 μm intervals effectively. Compared to the conventional chip form, the change of micro-structure assured the stability of the chips even after working for 150 min. Lysozyme, BSA and pepsin were separated from the μFFE with electric field intensity of 81.82 V/cm, sample flow rate of 3 μL/min and pH 5. The optimized chips successfully separated lysozyme BSA and calf thymus DNA, which demonstrated an excellent baseline-separation of protein and nucleic acid mixtures under milder separation condition. These results showed that optimized μFFE chips based integrated device can be potentially applied to prepare and analyze complex biological samples in the future for deep space exploration.