The microfluidic device, which can be used in clinics, is dubbed SPARTAN, short for Simple Periodic ARray for Trapping And IsolatioN. It uses a field of three-dimensional posts that create an obstacle course for the swimming sperm cells. The strongest and healthiest sperm get through this array the fastest and then are collected at the outlet to be used in the in vitro fertilization (IVF) process.
"With SPARTAN, we not only get sperm with excellent motility, but also with normal morphology and better DNA integrity, helping families worldwide by reducing the stress of multiple IVF procedures, while potentially increasing pregnancy rates." said Tüzel. "This could increase patients' chances of getting pregnant."
According to the Centers for Disease Control and Prevention, 12% of women in the United States between the ages of 15 and 44 deal with infertility issues. In that same age group, 7.3 million American women have used infertility services. And the National Institutes of Health reports that one-third of infertility cases are caused by male reproductive issues, while another third are caused by a combination of male and female reproductive issues or unknown causes.
The SPARTAN device is about 4 millimeters wide and 12 to 16 millimeters long. Sperm are simply injected into one end and the fastest and healthiest are collected on the opposite end for immediate use in in vitro fertilization. The device also prevents the type of damage to cells that can occur with traditional sorting methods, such as those using high-force centrifuges.
Because SPARTAN can be used in the fertility clinic, sperm do not need to be frozen and shipped to a lab for processing; the in-clinic sorting procedure takes between 5 and 30 minutes. Tüzel, who develops computational models of swimming organisms at the microscale, focused his part of the research on modeling the design of the SPARTAN device and used algorithms and fluid physics to model human sperm and how they move in such a complex environment.
Demirci's Stanford team created the overall experimental device designs based on Tüzel's theoretical models, fabricated and tested the prototypes, and determined the best experimental parameters and medium for the sperm cells to swim through the device. The study findings were published in the Advanced Science
"Our success was the result of our close collaboration, bringing theory and experiment together, WPI working with the Demirci Lab," said Tüzel. "And as a physicist, this is very exciting. We are going to have a product in the market helping people. That does not always happen in physics in such a short time frame, especially if you are a theoretical physicist."
"The collaboration between Erkan's lab and my lab is invaluable," he added. "WPI brings an outstanding theoretical tool that allows us to understand how microscale objects, such as sperm, interact with their environment; and we are able to design this know-how into real microfluidic devices, clinically validate what we designed, and experimentally improve it into a real-world application."