Comparing polyelectrolyte multilayer‐coated PMMA microfluidic devices and glass microchips for electrophoretic separations

Abstract

There is a continuing drive in microfluidics to transfer microchip systems from the more expensive glass microchips to cheaper polymer microchips. Here, we investigate using polyelectrolyte multilayers (PEM) as a coating system for poly (methylmethacrylate) (PMMA) microchips to improve their functionality. The multilayer system was prepared by layer-on-layer depositon of poly (diallydimethylammonium) chloride (PDAD) and polystyrene sulfonate (PSS). Practical aspects of coating PMMA microchips were explored. The multilayer buildup process was monitored using EOF measurements, and the stability of the PEM was investigated. The performance of the PEM-PMMA microchip was compared to those of a standard glass microchip and a PEM-glass microchip in terms of electroosmotic flow and separating two fluorescent dyes. Several key findings in the development of the multilayer coating procedure for PMMA chips are also presented. It was found that, with careful preparation, a PEM-PMMA microchip can be prepared that has properties comparable -and in some cases superior -to those of a standard glass microchip.

Selective Conversion of Polyenes to Monoenes by RuCl3‐Catalyzed Transfer Hydrogenation: The Case of Cashew Nutshell Liquid

“…By choosing polyelectrolytes that intentionally interact with the analytes, PEMs have been used by several groups as CEC coatings as summarized in a relatively recent review 13. Numerous groups, including ours, have employed PEMs as coatings on glass and plastic microfluidic chips 14–19. PEMs coatings have been found to effectively mask the underlying plastic substrate and resulted in more stable separations than the native substrate in as little as four layers.…”

Cationic isotachophoresis separation of the biomarker cardiac troponin I from a high‐abundance contaminant, serum albumin

“…It was also shown in the Kitagawa study that coating PMMA microchannel walls with PEIn created an anodic EOF which was stable for up to 32 days and over 50 runs . This anodic EOF was shown to be very low (−1.25 × 10 −4 cm 2 V −1 s −1 ) and the EOF was about four times lower and opposite in direction to that of untreated PMMA (4.93 × 10 −4 cm 2 V −1 s −1 ) .…”

Surface coatings for microfluidic-based biomedical devices

“…More extensive methods for further fi ne tuning can be employed as well. To further study the stabilization PEMs provide, devices made of various substrates have been compared for consistency in separation performance (Currie et al, 2009). In this study, PMMA and glass microchannels were coated with poly(diallyldimethylammonium chloride) and polystyrene sulfonate (PSS) and compared to non-coated glass channels to show that PEM-coated glass had a stable EOF that was independent of solution pH.…”