Microfabricated System for Parallel Single-Cell Capillary Electrophoresis

Performing single-cell electrophoresis separations using multiple parallel microchannels offers the possibility of both increasing throughput and eliminating cross-contamination between different separations. The instrumentation for such a system requires spatial and temporal control of both single-cell selection and lysis. To address these problems, a compact platform is presented for single-cell capillary electrophoresis in parallel microchannels that combines optical tweezers for cell selection and electromechanical lysis. Calcein-labeled acute myloid leukemia (AML) cells were selected from an on-chip reservoir and transported by optical tweezers to one of four parallel microfluidic channels. Each channel entrance was manufactured by F2-laser ablation to form a 20- to 10-μm tapered lysis reservoir, creating an injector geometry effective in confining the cellular contents during mechanical shearing of the cell at the 10-μm capillary entrance. The contents of individual cells were simultaneously injected into parallel channels resulting in electrophoretic separation as recorded by laser-induced fluorescence of the labeled cellular contents.