Quantitative semen analysis using fluorometric lateral-flow assay system for male fertility diagnosis

About one-third of infertility cases are attributed to male lifestyle-associated factors such as smoking, drug abuse, obesity, and psychological stress. These factors have been suggested as potential contributors to male infertility. High-quality semen is essential for successful fertility, and poor semen quality is a significant hurdle in achieving this outcome. Therefore, it is necessary to evaluate the concentration and quality of semen on-site without visiting a hospital. In this study, we developed two analytical systems using a fluorescence lateral-flow sperm (FLF-sperm) assay for the rapid and quantitative evaluation of sperm concentrations and quality. The sperm-specific protein (SP-10) was chosen as a target analyte to determine sperm counts. An immunostrip was fabricated to obtain quantitative fluorescence signals in a sandwich format. The SP-10 assay provides highly sensitive detection with a detection limit of 1.28 x 10 ⁶ /mL and produces a reactive signal proportional to the sperm concentration in clinical semen samples. Additionally, we established a sensing system using enzymatic cleavage to detect sperm quality based on hyaluronidase (HAdase) activity values, covering sperm concentrations from 1.8 x 10 ⁶ /mL to 140 x 10 ⁶ /mL. These quantitative sperm analysis systems allow users to easily interpret sperm counts and quality on-site for diagnosing male infertility and monitoring treatment progress.