关键词: 芯片电泳, 压力进样法, 推拉式

Abstract:

Chip electrophoresis as a typical microfluidic system involves many aspects,such as substrate material,microfabrication method,control of microfluid,separation modes and detection methods.As in conventional instrumental analyzing system,sample introduction is the first task to be addressed along the line of original sample to answer.Electroinjection has been the main stream method in chip electrophoresis.However,pressure injection method as alternative to electroinjection routinely used in conventional capillary electrophoresis system is seldom used in chip electrophoresis.Comparing to electroinjection,pressure injection is drawing attention in recent years for its major advantages in no electric discrimination and independence to surface charge properties of the sample transfer conduit.A good example of pressure injection for miniaturized capillary electrophoresis may be the successful incorporation of flow injection analysis system,where very high precision was achieved.In the light of typical cross or double T structure of chip electrophoresis,we present here a new sample introduction method based on pressure driven flow.Briefly,by making the inlet and outlet sample flow rates equal,well-defined sample plug was formed in the sampling zone,while the fluidic state in the separation channel remained unaffected.Sample introduction was achieved by stopping the flows upon the application of high voltage in free zone electrophoresis mode.The feasibility and performance were demonstrated by confocal microscope fluorescence detection and imaging with a chip electrophoresis of polymer substrate that was fabricated based on laser ablation and plasma aide adhesiveless bonding.This method was found promising especially for chip electrophoresis;meanwhile,it made the fluidic system more controllable.

Key words: Chip electrophoresis, Pressure sample introduction, Push-pull style