Improving Sperm Motility and Biosafety: A Novel Device for Density Gradient Separation

Abstract Objective: To evaluate the technical performance of a novel sperm preparation device (Reprostar) designed to improve motility recovery and minimize biological contamination during density gradient centrifugation. Design: Retrospective non-randomized cohort study. Patients: A total of 13,416 semen samples processed for intrauterine insemination (IUI). Interventions: Comparison of a conventional density gradient (DG) method with the Reprostar system (RS), a purpose-designed device featuring an integrated insert for precise gradient layering, sealed centrifugation, and direct pellet retrieval without exposure to contaminants. Main Outcome Measures: Post-/pre-treatment sperm motility ratio, sperm concentration, and age distribution of female partners. Results: Compared to the conventional DG method, the Reprostar system demonstrated significantly greater motility recovery (1.60 vs. 1.48; p < 0.001), despite being used in a cohort with slightly lower baseline sperm concentrations and higher average age of female partners. Additionally, it minimized carryover of seminal plasma and potential pathogens through enhanced separation efficiency and a closed handling system. These advantages indicate improved biosafety and procedural reliability under routine clinical conditions. Conclusions: This novel preparation system improves sperm recovery while reducing biological risk during semen processing for IUI. Combining superior technical performance with operational simplicity, it offers strong clinical value—particularly in high-throughput or resource-limited settings aiming to enhance IUI outcomes without resorting to invasive ART procedures.