Adsorption inhibition as a mechanism of freezing resistance in polar fishes.

TLDR

Polar fishes possess serum proteins and glycoproteins that protect them from freezing by a non‑colligative mechanism, and similar crystal‑growth‑inhibition models have been proposed for other systems. The study proposes a model in which adsorbed antifreeze proteins raise the curvature of ice growth steps, thereby depressing the freezing temperature. The model posits that antifreeze adsorption increases step curvature on the ice surface, inhibiting crystal growth. Experimental evidence shows antifreeze proteins are incorporated into ice, alter crystal habit to long needles aligned with the c‑axis, and adsorb to ice surfaces to inhibit growth.

Abstract

Polar fishes are known to have serum proteins and glycoproteins that protect them from freezing, by a noncolligative process. Measurements of antifreeze concentrations in ice and scanning electron micrographs of freeze-dried antifreeze solutions indicate that the antifreezes are incorporated in ice during freezing. The antifreezes also have a pronounced effect on the crystal habit of ice grown in their presence. Each of four antifreezes investigated caused ice to grow in long needles whose axes were parallel to the ice c axis. Together these results indicate the antifreezes adsorb to ice surfaces and inhibit their growth. A model in which adsorbed antifreezes raise the curvature of growth steps on the ice surface is proposed to account for the observed depression of the temperature at which freezing occurs and agrees well with experimental observations. The model is similar to one previously proposed for other cases of crystal growth inhibition.