Scanning electron microscopy of human spermatozoa after incubation with the spermicide nonoxynol-9.

The most frequently utilized spermicide in vaginal contraceptives is No-9. Schill and Wolff used TEM to demonstrate the focal effects of No-9 on human sperm and reported that No-9 damaged cell membranes and acrosomal membrane complexes. The present study by SEM was made to assess the extent of membrane damage due to the direct action of No-9 during an incubation period of only 5 minutes. SEM revealed that No-9 caused loosening and detachment of acrosomal, neck, and midpiece membranes of all sperm even at the lowest concentration tested (0.05%). The severity of membrane alterations observed in any of these regions would render sperm immotile and unable to penetrate the ovum. The fact that these alterations are produced within 5 minutes after exposure to No-9 attests to the effectiveness of No-9 as a vaginal contraceptive.