Application of femtosecond laser microsurgery in assisted reproductive technologies for preimplantation embryo tagging

Abstract

Femtosecond laser pulses were applied for precise alphanumeric code engraving on the zona pellucida (ZP) of mouse zygotes for individual embryo marking and their identification. The optimal range of laser pulse energies required for safe ZP microsurgery has been determined. ZP was marked with codes in three different planes to simplify the process of embryo identification. No decrease in developmental rates and no morphological changes of embryos post laser-assisted engraving have been observed. ZP thickness of embryos post laser-assisted code engraving has been shown to differ significantly from that of control group embryos at the hatching stage. Due to moderate ZP thinning as compared to its initial width at 0.5 dpc (days post coitum), readability of the code degrades slightly and it still remains recognizable even at hatching stage. Our results demonstrate that application of femtosecond laser radiation could be an effective approach for noninvasive direct embryo tagging, enabling embryo identification for the whole period of preimplantation development.

From Zygote to Blastocyst: Application of Ultrashort Lasers in the Field of Assisted Reproduction and Developmental Biology

“…Moreover, unconventional ART procedures can also be performed with femtosecond lasers. In this section, we briefly discuss two novel techniques based on the application of femtosecond laser pulses (Figure 2d-i): a technique for the individual labeling of preimplantation embryos [64,65] and one for controlled LAH [66].…”

“…There have been no differences in morphology and developmental rates in laser-labelled embryos compared with intact control embryos, and no statistically significant differences in the inner cell mass (ICM):TE ratio between these groups. Importantly, the engraved codes can be clearly recognized until the thinning of the ZP prior to hatching 4.5 days post coitum, enabling embryo identification for nearly the entire period of preimplantation development [65].…”

Preimplantation genetic testing as a component of root cause analysis of errors and reassignment of embryos in IVF

“…These guidelines require labelling of labware and double-checking procedures for patient identification, as well as a chain of custody for all patients' samples. Novel technological advances have also made use of radiofrequency identification technology, barcodes and, most recently, direct embryo tagging systems with silicon injectables for zygotes/embryos (Ilina et al, 2019). Ultimately, while the risks of embryo/gamete mix-up can be minimized by these interventions, they cannot be eliminated.…”

Controlled hatching at the prescribed site using femtosecond laser for zona pellucida drilling at the early blastocyst stage

“…Lasers with ultrashort pulse duration (~100-300 fs) allow the delivery of nanojoules (nJ) of energy per pulse during laser exposure, thus minimizing the possible risks of thermal damage to embryos. Femtosecond lasers have been successfully applied for fully noncontact optical microinjection and trapping of developing embryos [26], studying embryo morphogenesis [27], blastomere fusion [28,29], oocyte enucleation [30], TE cell dissection during embryo biopsy [31], and even for laser-assisted alphanumerical code engraving in the ZP for embryo identification during its preimplantation development [32,33].…”