ICSI media buffers: is there room for improvement?

Area of Science:

• Reproductive Biology
• In Vitro Fertilization
• Oocyte Handling

Background:

• Physiological extracellular pH (pHe) is critical for oocyte viability and embryonic development.
• Intracytoplasmic sperm injection (ICSI) temporarily inactivates oocyte pH regulatory mechanisms.
• HEPES- and MOPS-buffered media are standard in IVF but may have unaddressed biological effects.

Purpose of the Study:

• To review the current understanding of pH buffering in ICSI media.
• To explore the potential of bicarbonate-buffered media for improved embryological outcomes.
• To identify areas for future research in optimizing ICSI handling conditions.

Main Methods:

• Literature review and synthesis of existing research on pH buffering in IVF.
• Analysis of preliminary findings on bicarbonate-buffered media in human oocytes.
• Discussion of experimental limitations and clinical relevance.

Main Results:

• HEPES- and MOPS-buffered media have a long history of safe use in IVF.
• Concerns about zwitterion effects are often context-dependent and not fully representative of clinical practice.
• Emerging evidence suggests bicarbonate-buffered media may enhance embryological outcomes and transcriptomic profiles.

Conclusions:

• Current IVF media systems may not be fully optimized.
• Bicarbonate-buffered media present a promising avenue for improving ICSI procedures.
• Further standardized research is needed to validate bicarbonate-buffered media and optimize handling conditions for clinical application.