The spatula-shapedsetae arranged in lamellae on gecko footpads enable attractive van der Waals' forces between the β-keratin lamellae/setae/spatulae structures and the surface.[13][14] These van der Waals interactions involve no fluids; in theory, a boot made of synthetic setae would adhere as easily to the surface of the International Space Station as it would to a living-room wall, although adhesion varies with humidity.[15][16] The setae on the feet of geckos are also self-cleaning and will usually remove any clogging dirt within a few steps.[17][18] Teflon, which has very low surface energy,[19] is more difficult for geckos to adhere to than many other surfaces.

Increasing humidity typically fortifies gecko adhesion,[15][16][20][21][22] even on hydrophobic surfaces, yet is reduced if completely immersed in water. The role of water in that system is under discussion, yet recent experiments agree that the presence of molecular water layers (water molecules carry a very large dipole moment) on the setae as well as

on the surface increase the surface energy of both, therefore the energy gain in getting these surfaces in contact is enlarged, which results in an increased gecko adhesion force.[15][16][20][21][22] Moreover, the elastic properties of the b-keratin change with water uptake.[15][16][20] Friction experiments with gecko toes—torn parallel to surfaces—have shown to be influenced also by electrostatic forces.[23]

Gecko toes seem to be "double jointed", but this is a misnomer and is properly called digital hyperextension.[24] Gecko toes can hyperextend in the opposite direction from human fingers and 

toes. This allows them to overcome the van der Waals force by peeling their toes off surfaces from the tips inward. In essence, this peeling action alters the angle of incidence between millions of individual setae and the surface, reducing the van der Waals force. Geckos' toes operate well below their full attractive capabilities most of the time, because the margin for error is great depending upon the surface roughness, and therefore the number of setae in contact with that surface.

Use of small van der Waals attraction force requires very large surface areas: every square millimeter of a gecko's footpad contains about 14,000 hair-like setae. Each seta has a diameter of 5 μm. Human hair varies from 18 to 180 μm, so a human hair could hold between 12 and 1300 setae. Each seta is in turn tipped with between 100 and 1,000 spatulae.[17] Each spatula is 0.2 μm long[17] (one five-millionth of a meter), or

just below the wavelength of visible light.[25]

The setae of a typical mature 70 g (2.5 oz) gecko would be capable of supporting a weight of 133 kg (293 lb):[26][27] each spatula can exert an adhesive force of 5 to 25 nN.[20][28] The exact value of the adhesion force of a spatula varies with the surface energy of the substrate to which it adheres. Recent studies [22][29] have moreover shown that the component of the surface energy derived from long-range forces, such as van der Waals forces, depends on the material's structure below the outermost atomic layers (up to 100 nm beneath the surface); taking that into account, the adhesive strength can be inferred.

Recent studies have also revealed that apart from the setae, phospholipids—fatty substances produced naturally in their bodies—also come into play.[30] These lipids lubricate the setae and allow the gecko to detach its foot before the next step.

Biomimetic technologies designed to mimic gecko adhesion could produce reusable self-cleaning dry adhesives with many applications. Development effort is being put into these technologies, but manufacturing synthetic setae is not a trivial material design task.