Accurate 3D Images Could Significantly Improve IVF Treatments

Researchers at Tel Aviv University have developed a safe and accurate 3D imaging method to identify sperm cells that are moving at high speed.

The research was led by Professor Natan Shaked, from the Department of Biomedical Engineering, TAU College of Engineering, together with TAU PhD student Gili Dardikman-Yoffe. The new technology could provide doctors with the ability to select the highest quality sperm for injection into an egg during IVF treatment, which could increase the chances that a woman will become pregnant and be able to deliver a healthy baby.

“The IVF procedure was invented to help fertility problems,” explains Professor Shaked. “The most common type of IVF today is intracytoplasmic sperm injection (ICSI), which involves the selection of sperm by a clinical embryologist and injection into the woman’s egg. To that end, an effort is made to select the sperm cell that is most likely to create a healthy embryo. ”

Choosing the right cells to make a baby
Under natural fertilization in a woman’s body, the fastest sperm to reach an egg is supposed to have high-quality genetic material. Progressive movement allows this “best” sperm to overcome the true obstacle course of a woman’s reproductive system.

“But this ‘natural selection’ is not available to the embryologist, who selects a sperm and injects it into the egg,” says Professor Shaked. “Not only are sperm cells moving fast, but they are also mostly transparent under regular light microscopy, and cell staining is not allowed in human IVF. Imaging technology

existing that can examine the quality of sperm genetic material can cause embryonic damage, so also in the absence of more precise criteria, sperm cells are mainly selected according to external characteristics and their motility while swimming in the water in a plate, which is very different from the natural environment of a woman’s body.

“In our study, we seek to develop a completely new type of imaging technology that provides as much information as possible about individual sperm cells, does not require cell staining to enhance contrast, and has the potential to enable optimal sperm selection in treatments. fertilization “.
A hologram of sperm cells.

The researchers chose computed tomography (CT) technology for the unique task of sperm imaging.

“In a standard medical CT scan, the device rotates around the subject and sends out X-rays that produce multiple projections, ultimately creating a 3D image of the body,” says Professor Shaked. “In the case of sperm, instead of rotating the device around this little guy, we relied on a natural characteristic of the sperm itself: its head constantly rotates during forward movement.
We use weak light (and not X-rays), which does not damage the cell. We record a hologram of the sperm cell during ultrafast movement and identify various internal components according to their refractive index. This creates a highly dynamic and accurate 3D map of your content without using cell staining. ”

Using this technique, the researchers obtained a clear and precise CT image of the sperm at a very high resolution in four dimensions: three dimensions in space with a resolution of less than half a micron (one micron equals one millionth of a meter). and the exact time dimension (motion) of the second sub-millisecond. “Our new development provides a comprehensive solution to many known sperm imaging problems,” says Professor Shaked. “We were able to create high-resolution images of the sperm head as it moved rapidly, without the need for staining that could damage the embryo. The new technology can greatly improve the selection of sperm cells in vitro, increasing the possibility of pregnancy and the birth of a healthy baby.

“To help diagnose male fertility problems, we intend to use our new technique to shed light on the relationship between 3D movement, structure and content of sperm and their ability to fertilize an egg and produce a viable pregnancy,” concludes the Professor Shaked. “We believe that such imaging capabilities will contribute to other medical applications, such as the development of efficient biomimetic microbots to transport drugs within the body.”

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