Functional heterogeneity of sperm binding to the ZP2 N terminus across normospermic and infertile phenotypes

BACKGROUND: peptide can serve as a high-stringency selection tool to identify and enrich for morphologically superior and binding competent sperm. METHODS: . Binding efficiency was quantified using confocal microscopy. Morphometric analysis, including nuclear area and flagellum length, was performed on bound sperm and compared to sperm bound to native human zonae pellucidae. RESULTS: significantly enriched for morphologically normal sperm, increasing the proportion from a 1-5% baseline in raw semen to as high as 90% on the beads. Notably, 70-94% of bound sperm in the infertile group remained structurally atypical, suggesting molecular binding competence can be preserved despite gross morphological defects. CONCLUSION(S): beads provide a standardized, high-throughput functional proxy for the human zona pellucida. This assay transcends the diagnostic limitations of light microscopy by identifying physiologically competent gametes, offering a robust tool for targeted sperm recovery in assisted reproduction.