epithelial enlightenment.

This is a Pacific tree frog (Hyla regilla), with whom I made a brief encounter with whilst pulling a hose out of a hose pot in a client’s garden. I either disturbed him enough to want to jump out and attack my finger – or – he loved the nail polish and wanted a closer look. (Base coat – Essie: ‘Hi Maintenance’. Second coat – Deborah Lippmann: ‘Some Enchanted Evening‘. Top coat – Deborah Lippmann: ‘Addicted to Speed’. *Top coat is crucial to ensure optimum polish coverage for filthy gardeners.)

Once the hose came on, he quickly hopped off my hand and onto the closest wall. Tree frogs cling to surfaces with four toe pads on each hand. These pads are are sticky and allow them to grasp and hold onto surfaces through a hexagonal array of flat-topped epithelial cells, separated by mucus-filled channels. Under an atomic force microscope (a must own!), this `flat’ surface is highly structured at the nanoscale, consisting of a tightly packed array of columnar nanopillars. Each of these nanopillars has a central dimple that helps with the hold. The frog’s epithelium (toe skin) itself has an effective elastic modulus equivalent to silicon rubber, and allows them to stick but not get stuck on almost any surface.

Interesting, no?