Capillary electrophoresis (CE) is rapidly emerging as a powerful analytical tool for the low-level detection of nucleic acids, and offers an attractive alternative to the classic slab gel electrophoresis methods for DNA size separation and detection.
In CE, separation takes place in a thin fused silica-coated capillary, within which polymer buffer solutions (such as cross-linked polyacrylamide, agarose, nonlinear cross-linked polyacrylamide and entangled polymers) simulate the pore structure of a gel and function as a sieving medium for the separation of nucleic acids. Similarly to gel electrophoresis, the separation process occurs as a result of the preferential electrophoretic mobility of nucleic acids towards the anode. Detection of DNA fragments occurs on-line by means of UV absorbance or laser-induced fluorescence (LIF). For PCR products, fluorescent labels can be incorporated directly into the amplicon.
CE offers a number of advantages over conventional slab electrophoresis:
1) Fast run times (minutes rather than hours) enables high sample throughput analysis.
2) Highly sensitive detection.
3) CE separations allow very high resolution of complex samples.
4) Only small (nl) volumes of samples are injected into the capillary.
5) Direct quantitative information is available through integration of peak areas.
6) Automated injection, separation and detection make CE an efficient technique for high throughput sample processing.
In addition to the high purchase cost for the equipment, a major limitation for the routine analysis of nucleic acids by CE, is the requirement of expensive kits and skilled operators.
Chip based CE instruments are now on the market e.g. The Agilent 2100 Bioanalyzer , which are in a simple user friendly format. The LabChip� technology allows a user unskilled in CE to perform the analysis, as an understanding of capillary preparation and matrix design is not required.
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for an image of the 2100 Bioanalyzer (64KB)