Method of manufacturing nanochannels and nanochannels thus fabricated

The present invention relates to a method of fabricating at least one nanochannel in a semiconductor material applied on a substrate, comprising t he semiconductor material being subjected to an etching treatment and said substrate to a bonding treatment so as to attach a covering layer to the substrate, in which bonding treatment the semiconductor material is applied as bonding agent, and wherein prior to etching, the semiconductor material is locally doped for the formation of electrodes.Electrical Engineering, Mathematics and Computer Scienc

Fabrication of a glass-implemented microcapillary electrophoresis device with integrated contactless conductivity detection

Glass microdevices for capillary electrophoresis (CE) gained a lot of interest in the development of micrototal analysis systems (μTAS). The fabrication of a μJAS requires integration of sampling, chemical separation and detection systems into a microdevice. The integration of a detection system into a microchannel, however, is hampered by the lack of suitable microfabrication technology. Here, a microfabrication method for integration of insulated microelectrodes inside a leakage-free microchannel in glass is presented. A combination of newly developed technological approaches, such as low-temperature glass-to-glass anodic bonding, channel etching, fabrication of buried metal interconnects, and deposition of thin plasma-enhanced chemical vapour deposition (PECVD) silicon carbide layers, enables the fabrication of a CE microdevice with an integrated contactless conductivity detector. The fabrication method of this CE microdevice with integrated contactless conductivity detector is described in detail. Standard CE separations of three inorganic cations in concentrations down to 5 μm show the viability of the new μCE system

Micromachined glass apertures for artificial lipid bilayer formation in a microfluidic system

The use of spark assisted chemical engraving (SACE) to produce glass apertures that are suitable for the formation of artificial bilayer lipid membranes is described. Prior to use, the glass apertures were rendered hydrophobic by a silanization process and were then incorporated into a simple microfluidic device. Successful bilayer lipid membrane (BLM) formation and the subsequent acquisition of single-channel recordings are demonstrated. Due to the simplicity and rapidity of the SACE process, these glass apertures could be easily integrated into an all-glass microfluidic system for BLM formation

On-chip contactless four-electrode conductivity detection for capillary electrophoresis devices

In this contribution, a capillary electrophoresis microdevice with an integrated on-chip contactless four-electrode conductivity detector is presented. A 6-cm-long, 70-μm-wide, and 20-μm-deep channel was etched in a glass substrate that was bonded to a second glass substrate in order to form a sealed channel. Four contactless electrodes (metal electrodes covered by 30-nm silicon carbide) were deposited and patterned on the second glass substrate for on-chip conductivity detection. Contactless conductivity detection was performed in either a two- or a four-electrode configuration. Experimental results confirmed the improved characteristics of the four-electrode configuration over the classical two-electrode detection setup. The four-electrode configuration allows for sensitive detection for varying carrier-electrolyte background conductivity without the need for adjustment of the measurement frequency. Reproducible electrophoretic separations of three inorganic cations (K+, Na+, Li+) and six organic acids are presented. Detection as low as 5 μM for potassium was demonstrated

Capillary electrophoresis with on-chip four-electrode capacitively coupled conductivity detection for application in bioanalysis

Microchip capillary electrophoresis (CE) with integrated four-electrode capacitively coupled conductivity detection is presented. Conductivity detection is a universal detection technique that is relatively independent on the detection pathlength and, especially important for chip-based analysis, is compatible with miniaturization and on-chip integration. The glass microchip structure consists of a 6 cm etched channel (20 μm × 70 μm cross section) with silicon nitride covered walls. In the channel, a 30 nm thick silicon carbide layer covers the electrodes to enable capacitive coupling with the liquid inside the channel as well as to prevent interference of the applied separation field. The detector response was found to be linear over the concentration range from 20 μM up to 2 mM. Detection limits were at the low μm level. Separation of two short peptides with a pl of respectively 5.38 and 4.87 at the 1 mM level demonstrates the applicability for biochemical analysis. At a relatively low separation field strength (50 V/cm) plate numbers in the order of 3500 were achieved. Results obtained with the microdevice compared well with those obtained in a bench scale CE instrument using UV detection under similar conditions