What are gecko setae and how do they create adhesion?

Gecko setae are microscopic, brushlike, hairlike processes found on the lamellae (fine plates) located on the undersides of a gecko's toes.1

These structures are highly specialized for climbing:
* Structure: Each seta branches hundreds of times at its tip into tiny, spoon-shaped strands known as spatulae. These strands are incredibly fine, measuring less than 0.25 micrometres in diameter. A single tokay gecko can possess approximately half a million of these setae on each foot.1
* Adhesion: The gecko's ability to climb smooth, vertical surfaces—such as glass—is achieved through intermolecular forces that occur between the spatulae and the surface.1

While some sources describe these structures as microscopic hooks that catch on surface irregularities, the primary mechanism for the exceptional clinging ability of geckos is the interaction of these fine spatulae with the substrate at a molecular level. To disengage these structures, the gecko must curl its toes upward, a process that occurs with every step.231