Figure 1

The microfluidic system. (A): The reusable microfluidic chip and a slide with immobilized biological material are inserted in the docking station. When closed, the docking station provides the mechanical force for sealing of the flow chamber between the chip and the slide. The loaded docking station is placed on the stage of a microscope, and the capillaries from the microchip are connected to a liquid-controlling unit (not shown). (B): Inside the flow chamber, lanes of the immobilized biological material are sequentially exposed to sample. Two guiding streams (arrows) are used to obtain the desired flow trajectory of the sample stream, and these form a sheath on both sides of the sample, confining it between the guiding streams and the roof and the floor of the flow chamber. The distance between the sample stream and the previous lane is fully adjustable, and overlapping lanes can be produced. Adjusting guiding and sample flows controls the width of the sample stream, which can be as narrow as 25 μm, given that a precise fluid-controlling unit is used, and as wide as the chip allows. In the present study, 50–500-μm-wide sample streams were positioned in the central 3000 μm of the chip with gaps of 50–500 μm, in order to obtain defined lanes of comparable shape (only the straight part of lanes was included in the analyses).