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.