Title
A suction-free microICSI device reduces operator dependence in Piezo-ICSI: faster injection and improved survival trends in a novice operator
Background:
Piezo-intracytoplasmic sperm injection (Piezo-ICSI) is an effective micromanipulation technique, but its reliance on a holding pipette and bimanual handling may increase operator burden and limit procedural standardisation. A novel suction-free microICSI device stabilises the oocyte without suction and may simplify Piezo-assisted injection.
We investigated whether Piezo-microICSI (mP-ICSI) could reduce operator dependence by improving both procedural efficiency and oocyte survival across different experience levels.
Methods:
Immature human oocytes not used clinically were obtained with consent, matured in vitro overnight to metaphase II, vitrified, and later warmed. Using 4μm beads as sperm surrogates, bead injection was performed by mP-ICSI or conventional Piezo-ICSI.
Procedures were undertaken by two operators with markedly different human ICSI experience: one novice with only mouse piezo experience (no prior human ICSI) and one experienced clinical embryologist (ICSI since 2013). Immediate and Day-1 survival were assessed.
Procedure time was recorded per 5-oocyte set, from placement of the oocyte dish on the microscope stage to completion of the final injection. Degeneration rates were compared using Fisher’s exact test and procedure times using Welch’s t-test.
Results:
A total of 103 warmed metaphase II oocytes underwent bead injection (mP-ICSI, n=52; conventional Piezo-ICSI, n=51).
- Overall immediate survival was 76.9% (40/52) with mP-ICSI and 66.7% (34/51) with conventional Piezo-ICSI (+10.2 pp, p=0.279).
- Day-1 survival was 67.3% (35/52) and 56.9% (29/51), respectively (+10.4 pp, p=0.314).
Importantly, on conventional Piezo-ICSI both operators achieved identical immediate survival of 66.7% (18/27 novice vs 16/24 experienced), confirming equivalent baseline performance.
With mP-ICSI, the novice operator’s immediate survival increased to 82.1% (23/28; +15.4 pp) while the experienced operator remained stable at 70.8% (17/24).
Procedure time was significantly shorter with mP-ICSI for both operators: 378.0 ± 113.9 s versus 565.3 ± 92.1 s in the novice operator (p=0.045) and 427.3 ± 48.3 s versus 597.0 ± 93.8 s in the experienced operator (p=0.027).
Strikingly, the novice became the fastest operator with the device.
Conclusions:
In this pilot study using a human oocyte bead-injection model, the suction-free microICSI device significantly shortened procedure time for both novice and experienced operators while showing directional improvements in immediate and Day-1 oocyte survival, most pronounced in the novice. These findings suggest that mP-ICSI may reduce operator dependence, flatten the learning curve, and promote more standardised Piezo-ICSI workflows in ART laboratories.
Poster:
microICSI is designed to make intracytoplasmic sperm injection (ICSI) suction-free, simpler and more controlled, with fewer manipulations and less time under the microscope.
microBiopsy is a purpose-designed approach to blastocyst biopsy designed to improve procedural consistency while reducing technical burden across operators.
