Which is the safer method for trophectoderm biopsy in mouse blastocyst, mechanical or laser?

Introduction: This study was conducted to compare hatching rates after assisted hatching, re-expansion rates after trophectoderm biopsy, and survival rates after cryopreservation using different methods of assisted hatching and biopsy in mouse embryo. Materials and Methods: Five-week-old female mice (C57BL/CBA) were superovulated, and two-cell embryos were collected. All embryos were cultured to blastocyst stage. For assisted hatching and separating trophectoderm from blastocyst, laser device and hand-made pipette were used respectively. Hatching rates after assisted hatching, re-expansion rates after trophectoderm biopsy, and survival rates after cryopreservation were calculated. Results: Hatching rate was 92% in mechanically assisted hatching group and 90% in laser group, respectively. After mechanically assisted hatching, re-expansion rate was 91.3% and survival rate was 87% in biopsy by pipette and laser group, respectively. In laser hatching group, re-expansion rate was 88.9% with biopsy by pipette and survival rate was 84.4% with biopsy by laser. Conclusion: Throughout the study, mechanical technique and laser technique showed no differences in the safety profiles in trophectoderm biopsy procedure.