There are many couples in the world that despair the inability to have children. Studies have shown that most cases of infertility stem from males and are attributed to the inability of their sperms to fertilise healthy eggs. Sperms cells of such men often have low mobility with damaged genetic material (DNA). Research that allows the study of sperms requires that the sperm be destroyed, genetic material extracted and then chemically analysed.
Scientists have now developed a novel use for Renishaw’s Raman spectroscopy, wherein a non-destructive method of testing sperms can be employed. Heading the team at University of Edinburgh is Dr. Alistair Elfick, the brain behind this technique. According to him, it is the DNA of the sperm that is required to fertilise an egg and not the sperm itself.
In this method, scientists shine a focused beam of light on the 23 chromosomes in the head of the sperm to immobilize it, in a method known as optical tweezing. A damaged DNA refracts light differently form a healthy one, and this difference in refracted light is analysed by Raman spectroscopy to assess the state of the DNA. This light refraction data of a damaged DNA vis a vis a healthy DNA is used to determine the most likely sperm to bring about fertilisation and form a human embryo. This sperm could then be selected for IVF treatment, maximising the chances of successful fertilisation and potentially leading to more happy couples.
Says Michael Morris, a Raman spectroscopy expert at the University of Michigan, “It’s interesting research because is shows that there are finer distinctions for sperm other than dead or alive”.
To date, this procedure has not been included in IVF practice as there is still some scepticism surrounding the potential damage that a laser beam could do to a sperm. However, Alistair and Morris state that the energy contained in their laser beam is too small to cause permanent damage to the sperm.
Some scientists also fear the limitations that come with the technique, they being the inability to examine more than tens to hundreds of sperms at once. But the counter argument to those developing this technique is that a few hundred sperms is roughly the number of total sperms infertile men produce in a single ejaculation.
Despite all scepticism, research is still underway to also assess egg cells for in vitro fertilisation. As Dr Elfick concludes, “we are looking forward to more exciting work applying Raman to characterise cells for in vitro fertilisation both for human reproduction and for artificial insemination for domesticated animals.”