After removing the data corresponding to one and two particles, the average area of the capture beads was calculated by dividing the total area of aggregates by the number of aggregates. The areas where the pillars existed were excluded from the image analysis after the masking process of binarized images. Slopes of the time-dependent increase of the area of aggregate were obtained from linear regression of four data points (0, 5, 10, 15 min) (Figure and).