PDMS affixed bead array was incubated with three different dyes sequentially. Beads were incubated with indigo carmine (i) till the color was saturated, and then the dye was washed away completely and incubated with the second dye malachite green (ii). The third dye bromocresol purple (iii) was last incubated after malachite green was removed. A, B, and C three different areas were selected to zoom in for more clear visualization. Among total 11 beads with characteristic binding profile, #1, #3, #6, #8 and #11 beads only bind to malachite green. #4, #5 and #9 beads only bind to bromocresol purple. #2, #7 and #10 beads bind to both indigo carmine and bromocresol purple.