Microfluidic chips as a method for sperm selection improve fertilization rate in couples with fertilization failure.

PURPOSE: Sperm quality plays a vital role in successful fertilization and pregnancy. Patients with fertilization failure (total failure or low-fertilization rate) despite having normal semen parameters are a challenging group whose sperm cannot fertilize the oocyte via the intracytoplasmic sperm injection (ICSI) technique. Microfluidics is offered as a new method for proper sperm sorting. METHODS: This study aimed to evaluate sperm parameters, DNA fragmentation index (DFI), expression of phospholipase C zeta 1 (PLCZ1), and transition nuclear proteins 1 (TNP1) mRNAs in sperm selected by microfluidic sperm sorting (MSS) chip compared with conventional density gradient centrifugation technique in patients with fertilization failure following ICSI. Subsequence fertilization rate and embryo quality were assayed. RESULTS: Normal morphology and total motility were significantly higher, and DFI was significantly lower in sperm selected by the MSS chip in fertilization failure and control groups. The RT-PCR results demonstrated a significant increase in the expression of PLCZ1 and TNP1 genes in sperm of both groups selected by MSS chips compared to the DGC method. In addition, with the selected sperm by MSS chip, an increase in fertilization rate and improvement of embryo quality was obtained. CONCLUSION: The present study findings show that sperm sorting by the microfluidic method improves fertilization rate in patients with poor fertilization outcomes following ICSI.