Single-cell analysis using capillary electrophoresis: influence of surface support properties on cell injection into the capillary.

Capillary electrophoresis (CE) is an important tool of chemical cytometry. Whole-cell analysis using CE starts with cell injection into the capillary by either siphoning or electroosmosis. However, strong adherence of the cell to the support surface can prevent efficient cell injection and lead to irreproducible analysis. Here we evaluated several surfaces as potential cell supports for HT29 cells (human colon adenocarcinoma). These cells strongly adhered to the surface of untreated glass or polystyrene. Hydrophobic coating with dimethyldichlorosilane (DMS) or Sigmacote did not significantly reduce cell adhesion. In contrast, cell adhesion was reduced significantly when the surface was modified with hydrophilic polymers (hydrogels) such as poly(2-hydrohyethyl methacrylate) (PHEMA) and polyvinyl alcohol (PVA). In addition to their pronounced antiadhesive properties, PHEMA and PVA coatings were the most biocompatible (had highest survival of cells in contact with surface). Hydrogel-coated polystyrene plates were tested as a commercial alternative to hydrogel-coated glass slides. The cell adhesive properties of such plates were similar to those of PHEMA and PVA. However, the biocompatibility of the plates was lower than that of the other surfaces tested. Moreover, in contrast to PHEMA- and PVA-coated glass slides, the plates were sensitive to UV light and therefore should not be used when fluorescent image microscopy with UV excitation precedes CE. The analyses of the data obtained showed that PHEMA- and PVA-coated glass slides were the most suitable cell supports for cell injection into the capillary.