A protein's dance in a levitating droplet: how polymer length shapes a crystal's fate
A droplet the size of a pea hangs in the air, held up by inaudible sound. Inside it, the protein ferritin, the very one that stores iron in our bodies, begins its dance. The water leaves, the dancers get crowded, and they line up in neat rows: that is how a crystal is born. But this dance has a conductor: polyethylene glycol, a long chain of repeating units.