P-084 Novel Single-Step Microfluidic Chamber Outperforms Density Gradient Centrifugation in Post-Selection Motility And DNA Integrity
Authors: Vasilescu S , Lorimer J , Horta F , Warkiani M , Nosrati R 
Published: June 2022

Abstract

Study question
Does sperm selection by a novel single-step microfluidic chamber offer effective selection of motile sperm without DNA damage compared with Density Gradient Centrifugation (DGC)?

Summary answer
The novel single-step microfluidic chamber is a good alternative to conventional DGC, increasing DNA integrity and progressive sperm motility in recovered sperm populations.

What is known already
High levels of sperm DNA fragmentation (SDF) can have negative impacts on reproductive outcomes such as clinical pregnancy and miscarriage rates. Microfluidic sperm selection technologies have been developed to select sperm with lower level of SDF and higher levels of motility to improve Assisted Reproductive technology (ART) outcomes. While these methods have achieved variable success, very few have proven clinically relevant and fail to perform selection in a robust and simple methodology that can be adopted in clinics.

Study design, size, duration
A prospective cohort study including 21 donated semen samples processed in 2021. Each sample was split to perform DGC and microfluidic sperm selections side-by-side. Laboratory outcomes were evaluated using semen parameters pre and post processing and included concentration, motility, and DNA fragmentation index (DFI).

Participants/materials, setting, methods
The study was performed using samples donated at the Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia. DGC (10 minutes at 300g and 5 minutes wash at 300g) and microfluidic sperm selection (one-step sperm selection;15-minute incubation for selection) were performed with Sydney IVF 80/40 gradients and gamete buffers, respectively. DFI was assessed by chromatin sperm dispersion assay (SCD). Results were analysed by Friedman’s test and differences were considered significant when p-value &lt; 0.05.

Main results and the role of chance
For the unprocessed raw semen, the starting DFI values varied from 3.0 to 23.3% with an average of 11.38% ± 5.51 and motility varied between 25.3% and 86.7% with an average of 56.42% ± 18.57. The device consistently outperformed DGC in all 21 samples for DFI (0.94% ± 1.12 vs 4.87% ±3.69, P = 0.0012) and in 20 of the 21 samples for motility post-processing DGC (90.88% ± 6.8 vs 73.58% ± 14.97, P = 0.0061). The average concentrations of the raw, DGC, and microfluidic sperm samples were 94.5, 74.12, and 3.55 million sperm/mL, respectively. Thus, both DGC and the microfluidic device showed improvements in SDF, motility, and concentration over the raw sample. However, the microfluidic device significantly outperformed DGC in terms of percentage SDF and motility, indicating its potential for clinical implementation.

Limitations, reasons for caution
This cohort study did not include samples from infertile patients. Furthermore, the effect of each sperm selection methods on reproductive outcomes was not a part of the study. A larger number of samples across a range of clinically infertile samples is required to fully characterise the microfluidic devices efficacy.

Wider implications of the findings
The microfluidic device we report here has the potential to become a new tool to improve the efficacy and consistency of sperm selections. When compared to DGC it offers improved sperm motility and DNA integrity from a platform that is simple to use and less skill-based than conventional methods.

Trial registration number
not applicable