(a) Dried TRE solution (inset, SEM image of the outer periphery region), (b) dried LYS solution, (c) dried LYS-TRE solution (inset, SEM image of the outer periphery region), and (d) the locations of the outer periphery, periphery and the center of the dried droplet. X axis (position) in the figure corresponds to the radial distance from the center of the droplet.