Albumin coated copper-cysteine nanozyme for reducing oxidative stress induced during sperm cryopreservation.

In the present work, SOD mimetic nanozyme (NACu-Cys) consisting of Cu-Cys complex and nano-albumin (NA) were synthesized. After characterizing the nanozyme, its superoxide dismutase (SOD) behavior was evaluated by inhibition of the pyrogallol autoxidation method. The results revealed that NACu-Cys exhibited SOD mimetic activity with a half inhibition concentration (IC50) value of 7.0 × 10-3 µM and a turnover number (kcat) of 5.4 × 107 s-1. In the next step, this nanozyme was applied as a protective agent against oxidative stress induced by sperm cryopreservation. Increasing the motility, raising the viability and reducing the apoptosis occurred as a result of NACu-Cys additions to human sperm freezing medium. Comparison between the natural SOD and SOD mimic behavior of NACu-Cys revealed that this nanoparticle has the ability to be used as oxidative stress decrescent during cryopreservation process.