Device directs sperm to `go against the flow' to help infertility
Engineering researchers develop easy-to-use and inexpensive microfluidic
chip for sperm selection

Date:
March 31, 2022
Source:
Florida Atlantic University
Summary:
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.



FULL STORY ==========================================================================
The female genital tract can be a hostile environment for conception. Out
of about 100 million sperm, only a few hundred make it to the fallopian
tubes.

Guided by a directional movement called rheotaxis, sperm
cells swim against the cervical mucus flow to reach the egg for
fertilization. This journey, however, is even more critical when
considering infertility. Sperm motility -- the ability to swim the right
way -- is key.


==========================================================================
By taking advantage of this natural rheotaxis behavior of sperm,
researchers from Florida Atlantic University's College of Engineering and Computer Science 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.

Assisted reproductive technologies such as in vitro fertilization (IVF), intrauterine insemination and intracytoplasmic sperm injection all require healthy sperm cells for a successful outcome. Current centrifugation
methods for sperm sorting require multiple steps, multiple types of
equipment and take about two hours to isolate sperm cells. These methods
damage sperm during processing and induce significant DNA fragmentation
and oxidative stress.

Results of the study, published in the journal Analyst of the Royal
Society of Chemistry,showed that sperm cells isolated from the collecting chamber in this microfluidic chip exhibited significantly higher motility (almost 100 percent), a higher number of morphologically normal cells
and substantially lower DNA fragmentation, which is a crucial parameter
for the fertilization process. In addition, the developed chip provides
more than enough cells required for a successful intracytoplasmic sperm injection due to the amount and quality of sperm cells isolated using
the chip.

"Operating our chip is very easy. Once the semen is loaded into the
sample inlet chamber, the competent sperm cells start moving against
the fluid flow toward the collecting chamber from where they can easily
be collected," said Waseem Asghar, Ph.D., senior author, an associate
professor in FAU's Department of Electrical Engineering and Computer
Science, and a member of the FAU Institute for Human Health and Disease Intervention (I-Health) and FAU Institute for Sensing and Embedded
Network Systems Engineering (I-SENSE).

"Furthermore, this chip offers a one-step, one-hour operational
benefit, which an operator can use with minimal training." The study
also validates that rheotaxis selects the healthy, motile, and higher
velocity sperm cells for the fertilization process.



==========================================================================
"The assembly of the microfluidic chip is low-cost, and the reagents
used in the chip to separate sperm cells are only a few milliliters,
therefore, the commercial cost of the chip would be less than $5," said
Asghar. "Moreover, this technology will considerably reduce the economic
burden of fertility implementations and both the chip and the sperm cells isolated from it offer great clinical significance and applicability."
The microfluidic chip consists of four cylindrical chambers that are
connected through the microchannels. The four chambers are the fluid
inlet chamber, collecting chamber, sample inlet chamber, and waste
collection chamber. The channel between the collecting chamber and sample
inlet contains microgrooves to guide the sperm cells in addition to the
fluid flow for the rheotaxis movement of the sperm cells towards the
collecting chamber.

The shear stress inside the device is generated by fluid flow using
a syringe pump. A raw semen sample is then added to the sample inlet
chamber from where functional sperm cells will swim towards the collecting chamber, effectively separating themselves from dead and immotile sperm.

"Conventional centrifugation often compromises the integrity of sperm
cells.

This research study demonstrates that the microfluidic chip developed
by professor Asghar and his colleagues eliminates this issue," said
Stella Batalama, Ph.D., dean, College of Engineering and Computer
Science. "This novel technology offers a platform where the sperm cells experience different shear stress in different parts of the chip, which facilitates the isolation of competent sperm cells without impacting
their integrity." In the United States, an estimated 15 percent of
couples have trouble conceiving. Globally, approximately 48.5 million
couples experience infertility. According to the U.S. Centers for Disease Control and Prevention, 12 percent of women of childbearing age have
used an infertility service. All treatment costs for infertility can
range from $5,000 to $73,000. The average patient goes through two IVF
cycles, bringing the total cost of this procedure, including medications, between $40,000 and $60,000. An estimated 85 percent of IVF costs are
often paid out-of- pocket.

Study co-authors are Sandhya Sharma and Md. Alam Kabir, Ph.D. candidates
in the Asghar Laboratory, Micro and Nanotechnology in Medicine, FAU
Department of Electrical Engineering and Computer Science.

Video: https://youtu.be/SuxAZTVEB5Q

========================================================================== Story Source: Materials provided by Florida_Atlantic_University. Original written by Gisele Galoustian. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Sandhya Sharma, Md. Alamgir Kabir, Waseem Asghar. Selection
of healthy
sperm based on positive rheotaxis using a microfluidic device. The
Analyst, 2022; DOI: 10.1039/d1an02311j ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220331101456.htm

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