Complex sperm collective motion under physiologically relevant conditions

Collective motion of spermatozoa within the confined, viscoelastic milieu of the female reproductive tract is an underexplored determinant of fertilisation success. This MSCA project will uncover the physical rules that organise dense sperm suspensions into clusters, streams and turbulence-like flows, and test how environmental architecture and inter-ejaculate competition modulate these states. We will engineer physiologically inspired microfluidic landscapes with controlled curvature, viscosity/viscoelastic gradients and shear; record dynamics via phase-contrast and dual-colour fluorescence at high spatiotemporal resolution; and quantify both flow fields (PIV/PTV) and single-cell trajectories using deep-learning trackers. Mixed-donor experiments with spectrally barcoded sperm will reveal whether genetically distinct populations interact neutrally, cooperatively or competitively under confinement. These data will drive multi-scale theory—2D/3D agent-based simulations with hydrodynamic/alignment interactions and coarse-grained continuum models—closing the loop between prediction and device design. Hosted at Warwick’s CMCB (Kantsler: microfluidics; Turner: theory), the work will deliver open datasets, code and validated metrics of collective motility, and seed translation with Cytoswim toward diagnostics that assess “interaction-driven quality” rather than isolated single-cell parameters. Beyond fundamental advances in wet active matter, the outcomes will support animal fertility management in agriculture and conservation, aligning with EU priorities on food security and biodiversity.