A new polymer device for use with conventional particulate stationary phases for on-chip, fritless, capillary electrochromatography (CEC) has been realized. The structure includes an injector and a tapered column in which the particles of the stationary phase are retained and stabilized. The chips were easily fabricated in poly-(dimethylsiloxane) using deep-reactive-ion-etched silicon masters, and tested using a capillary electrophoretic separation of FITC-labeled amino acids. To perform CEC, the separation channel was packed using a vacuum with 3-µm, octadecylsilanized silica microspheres. The packing was stabilized in the column by a thermal treatment, and its stability and quality were evaluated using in-column indirect fluorescence detection. The effects of voltage on electro-osmotic flow and on efficiency were investigated, and the separation of two neutral compounds was achieved in less than 15 s.The use of microfabricated fluidic substrates has become increasingly well-established for liquid-phase analysis in recent years. This is particularly true for electrokinetically driven separations, where etched microchannels provide an easy route to reduced column diameters and, hence, increased efficiencies and decreased solvent/sample consumption. 1 As with narrow bore (<75 µm), fused-silica capillaries used in conventional capillary electrophoresis (CE) instrumentation, the high surface-to-volume ratios of these chip-based systems enable good dissipation of Joule heat. However, the shortest capillary that can be used in a benchtop instrument is generally no less than 30 cm long, which leads to typical applied electric field strengths on the order of a few hundred volts per cm. With chip CE, working with much shorter separation channels is facilitated, allowing electric fields of 500-1000 V/cm and decreased analysis times as a result. [2][3][4][5] The integration of picoliter-volume injection elements into etched CE devices is a further unique feature of the chip format. Microfluidic devices operated using pressure-driven flow 6,7 and centrifugal pumping [8][9][10][11] have also been reported, expanding the range of possible analyses. The microfluidic approach should generally enable high throughput applications, 12-14 as well as a high level of automation for real-time testing at the point of care (POC). [15][16][17] The many advantages of microfabricated devices for ultrasmallscale analysis have been demonstrated with a wide variety of examples, including sample preconcentration, 18,19 cell handling, 20,21

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Summary: In this study, microstructured surfaces are produced by a spatial arrangement of different functional domains by a combination of plasma polymerization and photolithography. Two different kinds of protein and cell adhesive patterns have been alternated with non‐fouling areas. Non‐fouling patterns are made of poly(ethylene oxide) (PEO)‐like polymers obtained by pulsed plasma polymerization of diethylene glycol dimethyl ether, which leads to coatings with a high concentration of ethylene oxide groups (>70%). Fouling surfaces are composed of PEO coatings with a low concentration of ethylene oxide groups (≈40%) and films containing amino groups (from allylamine monomer) obtained by plasma polymerization. High pattern fidelity is demonstrated by ellispometry measurements, whereas XPS and ToF‐SIMS analyses have been used to characterize the surfaces. Experiments with a model protein (bovine serum albumin) and cells (L929 mouse fibroblasts) on patterned surfaces show that proteins and cells only adhere on the patterns, whereas the background stays uncovered.

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