• Promising nanoparticles and delivery methods to improve Sperm Cryopreservation in assisted reproductive technology
  • Saman Sadegh-pour,1,* Sayed Mehrdad Azimi,2 Vajihe Asgari,3
    1. Department of Anatomical and Molecular Biology Sciences, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
    2. Department of Anatomical and Molecular Biology Sciences, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
    3. Department of Anatomical and Molecular Biology Sciences, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran


  • Introduction: Sperm cryopreservation (SC) as a crucial stage of assisted reproductive technology (ART) providing long-term storage of samples for procedures such as in vitro fertilization (IVF). Sperm damage can reduce fertility capacity in freeze-thaw process due to crystal formation, stress oxidative and osmatic shock. Glycerol and egg yolk buffer as conventional cryoprotectants may alleviate post-thaw injuries but have limitations. Therefore, nanoparticles emerge as a novel cryoprotective strategy. Various types of nanoparticles such as gold, silica, carbon nanotubes, and graphene have exhibited cryoprotective effects for sperm freezing due to proposed mechanisms include direct membrane stabilization, antioxidant effects, and regulation of apoptosis pathways. These mechanisms improve sperm motility, viability, acrosome integrity, and ATP levels. This is a brief background about potential effect of nanoparticles for sperm post-thaw preservation in ART. This review will provide an overview of current investigations focused on types of nanoparticles, combination and delivery methods in SC to highlight future prospect strategies to optimize the efficacy of SC in ART.
  • Methods: A comprehensive search strategy was implemented to identify relevant articles on the topic of sperm cryopreservation, nanoparticles and related keywords. Databases including PubMed, Web of Science, Scopus, and Google Scholar were searched for articles published from 2015 to 2023 for identify relevant articles on sperm cryopreservation and nanoparticles. The articles skimmed by two independent reviewers based on title/ abstract. All relevant studies were included. Non-English articles, and other applications of nanoparticles unrelated to cryopreservation were excluded and a flow diagram of the search strategy is listed.
  • Results: Studies have explored a variety of nanoparticles as novel cryoprotective supplements to improve post-thaw sperm quality in assisted reproduction. gold nanoparticles preserved sperm motility and viability better than other nanoparticles such as silver, silica, platinum, palladium and magnetic iron oxide. On the other hand, between metal oxide nanoparticles including ZnO, Fe3O4, CeO2, CuO, NiO, and Co3O4, investigations found CeO2 nanoparticles preserved post-thaw sperm motility and viability. Besides, Combinations of nanoparticles demonstrate synergistic benefits. Co-treatment with gold and cerium oxide nanoparticles resulted in improved sperm membrane and DNA integrity after freezing and thawing relative to individual nanoparticles. Silica nanoparticles supplemented with trehalose cryoprotectant better preserved post-thaw human sperm motility and mitochondrial activity compared to trehalose alone. Nowadays, several types of lipid or polymer-based nanoparticles have recently shown promise as sperm cryoprotectants.
  • Conclusion: Nanoparticles improve the cryopreservation of semen by reducing cytotoxicity and enhancing sperm parameters. Nanoparticles can target physical and physiological characteristics of sperm, such as motility, directionality, apoptosis, and intact acrosome, to predict whether a semen sample is suitable for ART. Incorporating delivery, warming, and washing methods into efficient cryopreservation is also being studied. Overall, the use of nanoparticles in semen cryopreservation is a promising area of research that could lead to improvements in ART success rates. Further optimization of nanoparticle-based freezing extenders may continue enhancing clinical outcomes. However, more investigations are needed to understand the potential benefits and limitations of this approach.
  • Keywords: Spermatozoa, Cryopreservation, Nanoparticles, Assisted Reproductive Technique