Pollen is a seasonal problem for millions of people around the world who suffer from allergenic reactions to the antigens embedded on the outer casing of these microscopic grains. The image below reveals tiny pollen grains that have been fixed and stained, then visualized under phase contrast illumination.

Tiny grains of pollen are released into the atmosphere by a wide spectrum of flowers, trees, weeds, grasses and other plants that reproduce seasonally. Although most of these fertilizing gametes seldom reach their destinations, many find their way into the noses and throats of unsuspecting humans where they illicit an allergenic reaction.

Commonly referred to as "hay fever", pollen allergies induce rhinitis and other effects that often cause sneezing, coughing, red and watery eyes, and related symptoms. An entire drug industry has arisen to deal with these unwanted medical effects, and for most people, a cure is as close as the nearest drug store or supermarket. Smaller numbers of people are more seriously affected and must undergo a more aggressive treatment.