Single-cell analysis using capillary electrophoresis: Influence of surfacesupport 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 cel l to the support surface can prevent efficient cell injection and lead to i rreproducible analysis. Here we evaluated several surfaces as potential cel l supports for HT29 cells (human colon adenocarcinoma). These cells strongl y adhered to the surface of untreated glass or polystyrene. Hydrophobic coa ting with dimethyldichlorosilane (DMS) or Sigmacote(R) did not significantl y reduce cell adhesion. In contrast, cell adhesion was reduced significantl y when the surface was modified with hydrophilic polymers (hydrogels) such as poly(2-hydrohyethyl methacrylate) (PHEMA) and polyvinyl alcohol (PVA). I n addition to their pronounced antiadhesive properties, PHEMA and PVA coati ngs were the most biocompatible (had highest survival of cells in contact w ith surface). Hydrogel-coated polystyrene plates were tested as a commercia l alternative to hydrogel-coated glass slides. The cell adhesive properties of such plates were similar to those of PHEMA and PVA. However, the biocom patibility of the plates was lower than that of the other surfaces tested. Moreover, in contrast to PHEMA- and PVA-coated glass slides, the plates wer e sensitive to UV light and therefore should not be used when fluorescent i mage microscopy with UV excitation precedes CE. The analyses of the data ob tained showed that PHEMA- and PVA-coated glass slides were the most suitabl e cell supports for cell injection into the capillary.