A new method to produce equally sized hemizonae pellucidae for the hemizona assay

Possible applications of a non-contact 1.48 μm wavelength diode laser in assisted reproduction technologies

Recently, one laser system has been introduced in IVF fulfilling all safety requirements, while achieving a high standard of reproducibility in terms of ablation diameter. This 1.48 microm wavelength indium-gallium-arsenic-phosphorus (InGaAsP) semiconductor laser offers a variety of laser applications to the embryologist. On the one hand, zona pellucida of oocytes or embryos can be manipulated in order to facilitate ICSI or biopsy and assist hatching, and on the other, spermatozoa may be paralysed or immobilized prior to usage. To conclude, the 1.48 microm diode laser provides a promising tool for the microdissection of subcellular targets. The diode laser stands out due to the rapidity, the simplicity and the safety of the procedure which is supported by healthy offspring after laser application.

Application of a 1.48-microm diode laser for bisecting oocytes into two identical hemizonae for the hemizona assay

Laser systems are very promising new technical tools in assisted reproduction. It was investigated if laser radiation can replace the mechanical cutting procedure via micromanipulator in the hemizona assay (HZA), a commonly used bioassay to determine the sperm-zona pellucida binding capacity. An oocyte was bisected precisely into two identical hemizonae with approximately 20 laser pulses (pulse length 30 msec) using a 1.48-microm diode laser. Compared with the conventional method using microscalpels for zona bisection, laser treated hemizonae showed equivalent sperm-binding and within the two groups there was no detectable difference between matching hemizonae in their capacity for tight sperm-binding. To evaluate whether laser radiation affects the outcome of the HZA when effects of certain substances are investigated, the spermatozoa were preincubated with human follicular fluid (hFF), which inhibits the binding of spermatozoa to zona pellucida in vitro. Supplementation with follicular fluid exerted an inhibitory effect in both groups. The hemizona index (HZI) showed no statistical differences between the two methods. Therefore, the 1.48-microm diode laser is a suitable new instrument for generating equally sized hemizonae. There is no use for holding pipettes and microscalpels, on the contrary, for performing the HZA the laser is a precise, very quick and easy to use new working tool.