Figure 2.

Influence from sensor size on incident flux in a system with diffusion limited binding from stagnant liquids. The arrows show the directions of the analyte flux, assuming that nothing binds outside the active sensor region. The planar infinite surface in (A) gives the lowest average incident flux. If the spot is smaller, as in (B), the binding rate will become higher, especially at the edges. The binding rate is also higher in (C), showing a one dimensional sensor, which gives an incident flux with cylindrical symmetry. The highest average flux to the active area occurs for radial symmetry and a point-like sensor, as shown in (D).