A simple comet assay for archived sperm correlates DNA fragmentation to reduced hyperactivation and penetration of zona-free hamster oocytes  Philip J Chan, Ph.D., Johannah U Corselli, Ph.D., William C Patton, M.D., John D Jacobson, M.D., Steven R Chana, Alan King, M.D.  Fertility and Sterility  Volume 75, Issue 1, Pages 186-192 (January 2001) DOI: 10.1016/S0015-0282(00)01655-1

Figure 1 Modified alkaline comet assay of dried sperm smear. The fixed sperm were stained with acridine orange, layered over with a mini-agarose gel, lysed, processed by using electrophoresis, and viewed under fluorescent microscopy. The images were captured by holding an inexpensive computer videocamera to the eyepiece of the microscope; a shareware imaging program was used to convert the images to gray scale for pixel analysis. (A), Electrophoresis equipment, with paper stickers on slides; (B), sperm nuclei, with normal intact DNA forming halos; (C), necrosis, with diffuse comet tails; (D), apoptosis, with fan-like distinct tails. Lighter DNA density at the center of each sperm nucleus represents increased fragmentation of DNA. Chan. Comet assay of archived sperm. Fertil Steril 2001. Fertility and Sterility 2001 75, 186-192DOI: (10.1016/S0015-0282(00)01655-1)