Figure 2.

The effect of particle size on focusing efficiency. a) The channel cross section of 20 µm × 10 µm is designed for 2 µm particle focusing. b) Fluorescence image of 2 µm red fluorescent particles in the final curve of the serpentine microchannel. A single equilibrium focusing location is seen in the straight channel region. c) The corresponding fluorescence intensity profile across the width (w) of the straight channel region. d) The channel cross section of 10 µm × 5 µm is designed for 0.92 µm particle focusing. e) Fluorescence image of 0.92 µm green fluorescent particles in the final curve of the same serpentine microchannel. f) The corresponding fluorescence intensity profile across the width (w) of the straight channel region. The FWHM is calculated from a fitted Gaussian curve. The white dashed lines represent the microchannel boundaries.