Ultra-thin microchannel-type electrophoresis chip for TIRFM-based single-DNA observation in the femtomole concentration

In this article, ultra-thin microchannel-type electrophoresis chip is presented to enhance the detection sensitivity of total internal reflection fluorescence microscopy (TIRFM) for both prism- and lens-type methods simultaneously. Very small thickness of the microchip is in particular helpful to acquire the better images of biomolecules near the bottom wall in the prism-type TIRFM using an upright microscope. This microchip has salient features in that its whole thickness can lie between 200 μm and 250 μm, taken into account, relatively shorter working distance (WD, 1.5–1.7) of high numerical aperture (NA, 1.4–1.65) optics. The design specifications of the chip for a fine control of micro- and nano-fluidics in the femtomole concentration are described.