Event

Efficient migration in complex environments is crucial for biological systems that search for a target across various length scales. Microswimmers’ motion, such as bacterial chemotaxis in complex environments, and mammalian sperm migration within the female reproductive tract, occur at macroscopic length scales.
Microswimmers must search and respond to biophysical and/or biochemical clues from the environment to regulate their motion according to the collected information. This regulation of motion is essential, as the searcher needs to perform various tasks at different regions or carry out a multiphasic search to locate targets. Therefore, identifying the relevant clues present in the microenvironment, as well as their regulatory effect on the searcher’s motion, is key.
As a model system, we study bull sperm motion using microfluidics and apply concepts from soft matter and statistical physics to understand how sperm regulates its motion in a complex environment. I will present a quantitative yet overarching description of the regulation of sperm motility in response to the biophysical/biochemical clues within the female reproductive tract. We develop a holistic view that shows sperm motility can be categorized into multiphasic motions, including progressive, hyperactive, and circular. I will further discuss the outcomes of such interactions between sperm, biochemical stimulants, and biophysical clues, including the rheological properties of mucus and the architecture of the microenvironment.
Leveraging this understanding, I will demonstrate new platforms that can evaluate and, with exquisite precision, isolate samples with high motility to improve animal breeding and the quality of human life through improved assistive reproductive technologies. Further, the approaches and tools we have developed can be applied generally to the locomotion and search strategies utilized by living microorganisms and non-living systems such as biopolymer-colloids/colloidal suspensions under dynamic and non-equilibrium conditions.