Magnetic nanoparticle-based sperm selection: Progress and prospects for improving semen quality and fertility in livestock.

Semen nano purification represents an innovative advancement in livestock reproductive biotechnology, offering a targeted, non-invasive approach to sperm selection. Traditional semen processing techniques, such as centrifugation, swim-up, and density gradient methods, primarily rely on physical characteristics like motility and morphology, which often fail to eliminate apoptotic, acrosome damaged or functionally impaired spermatozoa. In contrast, magnetic nano-purification enables selective removal of defective sperm based on molecular surface markers, including phosphatidylserine, ubiquitin, acrosomal glycans and other membrane proteins associated with specific conditions. This review explores how understanding sperm subpopulation diversity and surface biomarker expression provides a foundation for advanced, fertility-driven sperm selection strategies. It further discusses the principles of magnetic nanoparticle synthesis, surface functionalization, and the practical workflow of semen purification. Comparative studies demonstrate that nano-purified spermatozoa exhibit superior membrane integrity, motility, mitochondrial activity, and DNA quality while reducing oxidative stress. Notably, field trials have shown enhanced conception rates with nano-purified semen at half the conventional sperm dose. The method's low cost, safety, and ease of use in field settings make it a practical option for its utility in artificial breeding programs. Future perspectives highlight its potential for multiplexed selection and non-invasive sex-sorting through sperm surface biomarker-specific conjugation. Collectively, magnetic nano purification stands as a transformative strategy to improve sperm quality, enhance reproductive outcomes, and support genetic advancement in livestock production systems.