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.

采用多并行微通道开展单细胞电泳分离，可同时实现分离通量提升与不同分离过程间交叉污染的规避。此类系统的仪器装置需实现单细胞分选与裂解的时空精准调控。为解决上述问题，本研究提出一种适用于并行微通道单细胞毛细管电泳的紧凑型平台，该平台集成了用于细胞分选的光镊与机电裂解模块。实验中，钙黄绿素标记的急性髓系白血病（acute myeloid leukemia, AML）细胞从芯片储液池中被分选得到，并通过光镊输送至四条并行微流控通道中的一条。每条通道的入口均通过F₂激光（F2-laser）烧蚀工艺制备，形成20至10微米的锥形裂解储液池，构建出可在10微米毛细管入口处对细胞进行机械剪切时有效束缚细胞内容物的进样构型。单个细胞的内容物可被同时注入并行通道，实现电泳分离，其过程通过标记细胞内容物的激光诱导荧光进行记录。