Hirohisa Abe

Fast separation of oligonucleotide and triplet repeat DNA on a microfabricated capillary electrophoresis device and capillary electrophoresis.

A laser‐induced fluorescence detection system coupled with a highly sensitive silicon‐intensified target (SIT) camera is successfully applied to the imaging of a band for DNA fragment labeling by fluorescence dye in a microchannel, and to the visualizing of the separation process on a microfabricated chip. We demonstrated that an only 6 mm separation channel is sufficient for the separation of triplet repeat DNA fragment and DNA molecular marker within only 12 s. The separation using the microfabricated capillary electrophoresis device is confirmed to be at least 18 times faster than the same separation carried out by conventional capillary electrophoresis with 24.5 cm effective length. The use of a short capillary with 8.5 cm effective length is also efficient for fast separation of DNA; however, the microchip technology is even faster than capillary electrophoresis using a short capillary.

Field-inversion electrophoresis on a microchip device

We have proposed a field‐inversion electrophoresis on a microchip for a shorter effective length, and investigated the external frequency for the DNA analysis based on the field‐inversion electrophoresis device. By using the optimized frequency, we demonstrated that the field‐inversion electrophoresis has great potentials for the separation of DNA fragments with shorter effective length.

Integrated micro chamber for living cell analysis with negligible dead volume sample injector

We develop the micro chamber for real-time monitoring of living cell. It is integrated with an extremely low dead volume sample injector. The chamber was fabricated by the combination of isotropic etching and deep trench etching using CCP-RIE and ICP-RIE. The reproducible sample injection of the order of 1 nL is performed. Biological cell culture of HeLa is also demonstrated in a prototype device.

Microfabricated CE Chips with Optical Slit for UV Absorption Detection

We have developed novel μ-CE chips with “on chip” optical slit which cut off the stray light in order to improve the sensitivity of the optical absorption detection on μ-CE chips. Our chips which have an optical slit at the bonding interface have been successfully fabricated on synthesized quartz glass substrates using HF (hydrofluoric acid solution) bonding method [1],[2]. The signal level of UV absorption detection was improved about ten times by applying the “on chip” optical slit compared with that of conventional µ-CE chips.

Microfabricated Chips for Capillary Electrophoresis on Quartz Glass Substrates Using a Bonding with Hydrofluoric Acid

Fabrication method and characteristics of micro capillary electrophoresis (μ-CE) chips fabricated on synthetic fused silica (quartz glass) substrates are described. A novel room temperature bonding method with hydrofluoric acid solution is applied [1], [2]. Advantages of this method are low thermal damage, low residual stress due to the room temperature bonding and simplicity of the bonding process which are expected for the assembly of microfluidic devices. The migration time variations are investigated to confirm the reproducibility of the fabricated μ-CE chips.

Monitoring Cellular Events in Living Mast Cells Stimulated with an Extremely Small Amount of Fluid on a Microchip

We successfully developed a measurement system for real-time analysis of cellular function using a newly designed microchip. This microchip was equipped with a micro cell incubation chamber (240 nl) and was stimulated by a very small amount of stimuli (as small as 24 nl). Using the microchip system, cultivation of mast cells was successfully carried out. Monitoring of the cellular events after stimulation with an extremely small amount of fluid on a microchip was performed. This system could be applicable for various types of cellular analysis including real-time monitoring of cellular response by stimulation.

Evaluation of Silanol Concentration on Quartz Glass Surface for EOF Stability of CE Chip

The effects of heat treatment during fabrication process and NaOH treatment after fabrication on surface silanol (Si-OH) concentration profile are discussed. FTIR-ATR (Fourier transform Infrared Spectroscopy - Attenuated Total Reflection) method is applied to measure the surface OH concentration of materials. The result revealed that FTIR-ATR can be a simple solution for estimation of OH concentration on the glass surface.