A rapid and reliable bonding process for microchip electrophoresis fabricated in glass substrates

Abstract

In this report, we describe a rapid and reliable process to bond channels fabricated in glass substrates. Glass channels were fabricated by photolithography and wet chemical etching. The resulting channels were bonded against another glass plate containing a 50-microm thick PDMS layer. This same PDMS layer was also used to provide the electrical insulation of planar electrodes to carry out capacitively coupled contactless conductivity detection. The analytical performance of the proposed device was shown by using both LIF and capacitively coupled contactless conductivity detection systems. Efficiency around 47,000 plates/m was achieved with good chip-to-chip repeatability and satisfactory long-term stability of EOF. The RSD for the EOF measured in three different devices was ca. 7%. For a chip-to-chip comparison, the RSD values for migration time, electrophoretic current and peak area were below 10%. With the proposed approach, a single chip can be fabricated in less than 30 min including patterning, etching and sealing steps. This fabrication process is faster and easier than the thermal bonding process. Besides, the proposed method does not require high temperatures and provides excellent day-to-day and device-to-device repeatability.

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

“…New procedures were described in the last two years for the fabrication of PMMA , PDMS , glass , and hybrid glass/PDMS microchips employing C 4 D. For MCE‐C 4 D devices, the precise geometry of the sensing electrodes and their positioning close to the separation channel are of key importance and much more critical than for standard capillaries and several new approaches for their fabrication have been described in the last two years. Zhao et al used thermal bonding of two glass wafers for microchip fabrication.…”

Epithelial cancer biomarker EpCAM determination in peripheral blood samples using a microfluidic immunosensor based in silver nanoparticles as platform

“…The construction of microfluidic immunosensor was carried out according to the procedure proposed by Segato et al with the following modifications [28].…”

Fast and versatile fabrication of PMMA microchip electrophoretic devices by laser engraving

“…Among those devices designed for custom analytical and bioanalytical applications, microchip electrophoresis (ME) devices are some of the most important ones [6][7][8]. A variety of strategies have been employed in the production of devices for ME ranging from standard photolithography [9] to rapid prototyping [10][11][12] and assembly [13]. Although photolithographic techniques have been traditionally used to produce high-end devices using silica-based substrates, the process can be time-consuming and render chips that are (often) too expensive for most research laboratories.…”