A novel microchip for capillary electrophoresis with acrylic microchannel fabricated on photosensor array

We have fabricated an integrated micro-electrophoretic chip by implementing an acrylic microfluidic channel directly on top of a photosensor array using a new microfabrication process. The cross-section of the microchannel is 100 μm high×100 μm wide, and the effective length is 4.5 cm. The photosensor consists of 147×147 pixels, each measuring 39 μm×39 μm. The integrated microchip is able to detect electrophoretic signals in real time along the whole microchannel as a two-dimensional image. The microfabrication process named “stereolithography with double controlled surface (SD method)” has been newly proposed in order to realize a highly transparent microchannel with a smooth surface without assembly processes such as bonding of two plates. The accuracy of fabrication is within 5% of the designed values. e also evaluated the performance of the fabricated microchip and confirmed its functionality. After a sample (blue dextran) was injected into the microchannel, significant values of absorbance were obtained from the photosensor along the whole microchannel. The absorbance was proportional to the concentration of blue dextran. Furthermore, gel capillary electrophoresis was performed on-chip for a mixture of two proteins. The separation process was visualized by the chip as a sequence of two-dimensional images in real time.