Trophectoderm biopsy. a simplified mechanical method

Abstract

Trophectoderm biopsy is an emerging approach in preimplantaion genetic diagnosis. The most recent introduction of laser technology has facilitated this step considerably.Worldwide the majority of the IVF clinics performing trophectoderm biopsy are using the laser for zona drilling. But, the cost of laser is considered high. Blastocyst trophectoderm biopsy using micromanipulation methods was first reported by Dorkas et al. (1990); however, new improvements are still needed. The objective was to evaluate a simplified, inexpensive method to remove trophectoderm cells. Discarded day-6 expanded or hatching blastocysts of more than 140 hours post insemination from IVF/ICSI were used to evaluate a simplified mechanical method for removal of trophectoderm cells. Trophectoderm biopsies were conducted under mineral oil in Falcon 1006 Petri dishes in 10 μl drops of G-MOPS medium without protein (Vitrolife Sweden AB). An Olympus IX70 equipped with integra Ti micromanipulation system and a tool holder with an opthalmic surgery micro blade (Micro Feather Blade # K-722) were used to perform biopsies. Blastocysts were placed individually in G-MOPS medium without holding pipette. The protruding trophectoderm was at 12 o'clock position. Excision of the trophectoderm cells was achieved with the assistance of the micro blade. Ten microliters of blastocyst medium with 20% of protein was added to the biopsy drops. Embryos and cells were rinsed and moved to the culture medium for a short evaluation. A total of 42 hatching blastocysts were biopsed. All the blastocysts survived the biopsy procedure. Trophectoderm cells were removed from the biopsy dish to the rinse dish with no problem. Further development of manipulated embryos or cells were not apparently impaired. All biopsies were performed in less than 90 seconds. These results demonstrate the feasibility of the trophectoderm biopsy using a practical mechanical method.