Topic: Real-time quantitative detection of single sperm cell dynamics and photodamage using optical tweezers

Date: September 20, 2024 (Friday)

Time: 15:30-16:30

Venue: TD301

Speaker: Prof. Jinhua ZHOU & Prof. Zhensheng ZHONG 

Host: Prof. Gang CHEN

About the speaker:

周金华，湖南华容人，民主促进会会员，博士，教授，硕士生导师，现任安徽医科大学生物医学工程学院副院长，中国光学学会第三届生物医学光子学专业委员会，安徽省增材制造协会医疗分会副会长，中国生物医学工程学会资深会员，中国光学学会高级会员，《中国医学装备》杂志第四届和第五届编委，JBHI,OLEN,Opt.Lett,OE等十余种国内外期刊审稿人。

Dr. Zhong Zhensheng, hailing from Dongguan, Guangdong, is an Associate Professor at the School of Biomedical Engineering, Anhui Medical University. He serves as a peer-review expert for the National Natural Science Foundation of China. His primary research interests include using single-cell mechanics to address biological and medical challenges and employing single-molecule mechanics to study nucleic acid folding mechanisms, as well as developing detection technologies based on complex nucleic acid structures. He has led and completed multiple research projects and has published over 20 SCI research articles. He got his BSc in Biological Sciences at USTC (2006-2010) and PhD in Biochemistry at NTU, Singapore (2011-2016). He was a Deputy Associated Researcher, School of Physics, Sun Yat-sen University (2016.10-2021.08).

Abstract: Male factors account for about half of all infertility cases, and sperm motility is an important criterion for the diagnosis of male infertility. Due to the high swimming speed of sperm, standard sperm motility analysis methods, such as computer-assisted sperm analysis, struggle to track the same sperm multiple times. On the other hand, to reduce procedure time and improve consistency and reproducibility, laser is widely proposed to be applied in assisted reproductive technologies, including sperm fixation, sperm selection, and intracytoplasmic sperm injection. However, quantitative studies on laser-induced photodamage of sperm are lacking. In this study, by using optical tweezers, we established a method to evaluate the mobility of human sperm. Our study revealed the dose effect of laser irradiation on photodamage of individual sperm cells, which provides an experimental basis for optimization of laser application in assisted reproductive technology to reduce photodamage-induced biosafety risks in the future. We proved that the real-time motility of sperm can be characterized by longitudinal rolling parameters using optical tweezers. Our study also revealed that as trapping time and laser power increase, the longitudinal rolling frequency of the optically trapped sperm decreases with an increasing percentage of pausing duration. This indicates the effect of laser power and duration on photodamage of individual sperm cells. This study provides a reference for future research on photodamage-prevention methods in laser-based sperm manipulation.

Key words: Optical tweezers; human sperm, photodamage; laser; assisted reproductive techniques