Out of about 100 million sperm, only a few hundred make it to the fallopian tubes. A directional movement called rheotaxis, guides sperm cells to swim against the cervical mucus flow to reach the egg for fertilization. Swimming the right way is key, especially for those combating infertility. Using this natural rheotaxis behavior of sperm, researchers have developed a microfluidic chip for sperm sorting that is fast, inexpensive, easy to operate and efficiently isolates healthy sperm directly from semen. Importantly, it effortlessly collects sorted sperm cells from the collecting chamber while minimizing contamination by deformed or dead sperm cells.
