Fig. 5.

Cartoon to show immobilized particles with the air–water interface well above the particle (A) and with the interface touching the particle (B). In the ideal case, like that shown schematically in A, particles bound to a structure-friendly support film (slide) are not at risk of becoming denatured at the air–water interface as long as the surrounding layer of buffer remains thicker than the size of the particle. As the layer of buffer becomes thinner and thinner, however, the air–water interface must eventually touch the particle, as shown in B