Poster Presentation ESA-SRB 2023 in conjunction with ENSA

Engineering functionalised surfaces that selectively capture suboptimal spermatozoa for applications in human IVF (#358)

Soraya Rasi Ghaemi 1 , David Sharkey 1 , Nicole McPherson 1 , Krasimir Vasilev 2 , Sarah Robertson 1
  1. Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
  2. Flinders University, South Australia, Adelaide, Australian Capital Territory, Australia

Selecting viable sperm for successful fertilisation and optimal developmental competence is an unmet challenge in reproductive medicine. There are limitations of methods based solely on motility and morphology criteria and this has prompted innovative approaches. Advances in understanding of the immunobiology of female reproductive tract sperm selection shows a role for immune cells in sperm selection. Knowledge of the relevant biomolecules provides novel avenues to develop surface chemistry-based approaches to emulate the molecular interactions between suboptimal sperm and immune cells. We have investigated plasma polymerisation approaches to recapitulate immune-mediated sequestration of suboptimal sperm on functionalised glass surfaces. We applied a plasma polymerised polyoxazoline (PPOx) film to glass using 2-methyl-2-oxazoline monomer. The PPOx film enabled covalent binding of antibodies reacting with suboptimal sperm in a concentration-dependent manner. In pilot experiments, samples of human donor sperm were introduced to the activated surface and the rate of sperm attachment was measured to define optimal surface coating parameters. We then applied similar surface functionalisation to antibody-coated glass channelled-slides and showed that unattached sperm recovered after introduction of neat semen exhibit superior functional characteristics compared with sperm prepared by standard swim-up or uncoated channelled slides. Recovered sperm were assessed by flow cytometry to measure proportions of viable sperm (propidium iodide) and apoptotic sperm (Annexin V expression), as well as reactive oxygen species (CellROX Green), and sperm DNA fragmentation (HALO-sperm assay)(n=3-5 per assay). Sperm recovered from functionalised channelled-slides had a significantly lower Annexin V+ sperm subpopulation (mean±SEM, 6.3±1.1%) compared with sperm prepared by standard swim-up (19.0±4.1%, P<0.05, ANOVA). The proportion of sperm exhibiting DNA fragmentation was also significantly decreased after functionalised channelled-slide use (5.7±1.2%) compared with swim-up (11.5±3.1%, P<0.05, ANOVA). In conclusion, our findings demonstrate the efficacy of surface functionalised antibody-coated channelled slides and their potential in preparing high-quality sperm for use in ART.