The study, titled “Ambient Temperature Transport of Human Oocytes: An Unexpected Research Resource,” explored the potential of immature oocytes from young egg donors at The World Egg and Sperm Bank in Phoenix, AZ. A total of 432 oocytes, collected from controlled ovarian stimulation cycles, were shipped overnight in a specialized transport medium designed to mimic the follicular environment. The medium included caffeine, dibutyryl cyclic-AMP, estrogen, progesterone, and, in some cases, zinc sulfate (ZnSO4). Remarkably, over 95% of the oocytes remained viable upon arrival, with many demonstrating meiotic progression or spontaneous activation after culture.

Key Findings:
High Viability: More than 95% of oocytes survived ambient temperature transport, whether supplemented with zinc or not, showcasing the robustness of the transport protocol.
Meiotic Competence: Transported oocytes exhibited meiotic progression, with some advancing to metaphase II or undergoing spontaneous activation, particularly when zinc was included in the transport medium.
Spontaneous Activation: Oocytes transported with zinc showed a higher incidence of spontaneous activation and cleavage activity, progressing to 2-, 4-, and even 8-cell stages during extended culture, as observed through time-lapse imaging.
Research Potential: The study highlights the potential of using “discard” oocytes—typically unsuitable for clinical use—as a valuable resource for studying oocyte biology and developing parthenogenetic stem cells, which could offer ethical and practical advantages over embryonic stem cells.

“This work demonstrates that immature human oocytes can be transported at ambient temperature without compromising their viability or research potential,” said lead author Dr. Maria G. Gervasi, a collaborating Bedford Research Scientist. “These findings provide a novel, experimentally tractable resource that could transform our understanding of human oocyte biology and enhance stem cell research.”

The transport protocol was designed for simplicity, requiring minimal effort from clinical teams. Oocytes were placed in cryotubes with the ambient temperature transport medium (ATTM), packaged in insulated Styrofoam boxes, and shipped overnight. Temperature sensors ensured conditions remained within a safe range (32–45°C). Upon arrival, oocytes were either fixed for immediate analysis or cultured for up to 5 days, with time-lapse and fluorescence imaging used to monitor viability, meiotic status, and activation.

The study also underscores the role of zinc in enhancing oocyte behavior. Oocytes transported with zinc exhibited increased spontaneous activation and cleavage, suggesting that zinc may influence meiotic maturation and early developmental processes. These findings align with prior research on zinc’s role in reproductive physiology and warrant further investigation.

Implications for Reproductive Medicine and Stem Cell Research: This research addresses a critical gap in human oocyte studies, where access to viable research material has been limited. By repurposing immature oocytes from egg banking, the study offers a sustainable and ethical source for advancing assisted reproductive technologies (ART) and stem cell therapies. Potential applications include improving clinical outcomes for ART, understanding causes of meiotic arrest, and developing parthenote stem cells, which have fewer ethical concerns and reduced tissue antigen complexity compared to embryonic stem cells.

“We are grateful to The World Egg and Sperm Bank and the donors whose contributions made this research possible,” said co-author Dr. Ann A. Kiessling of the Bedford Research Foundation. “This collaboration highlights the potential to transform discarded biological material into a powerful tool for scientific discovery.”

Limitations and Future Directions: The study acknowledges variability in oocyte behavior, likely due to differences in donor responses to ovarian stimulation. Future research will focus on optimizing the transport medium and systematically studying patient-specific factors to enhance meiotic competence and activation outcomes. The researchers also aim to explore the mechanisms behind zinc’s effects and the potential for scaling up parthenote stem cell derivation.

Availability: The study, published on June 21, 2025, is available online at https://doi.org/10.1007/s10815-025-03548-9. Supplementary materials, including time-lapse videos, can be accessed through the journal’s website.

About Bedford Research Foundation: The Bedford Research Foundation is dedicated to advancing biomedical research, with a focus on reproductive biology and stem cell technologies. Supported by the ESHE Fund, the Foundation collaborates with leading institutions to address critical challenges in human health.

Our circadian rhythm studies continue to reveal unique characteristics of activated eggs. Research published in early 2024 by BRF scientists describes circadian-controlled pathways not previously known to function in activated human eggs. As a consequence, novel circadian-controlled signals released by the embryo have now been discovered.

These findings add to the growing evidence that biological rhythms play a more central role in early development than previously understood—and that timing itself may be a key variable in how we activate and sustain viable human cells in the lab.

This research also raises urgent questions for the field of cell culture: if circadian signals are active this early, we may need to take them into account to keep cells alive and healthy in the lab. It’s possible that many IVF clinics—and research labs—are using culture conditions that don’t reflect the biological timing cues embryos rely on.

One striking insight from the publication is the possibility that the 8-cell embryo may be secreting oxytocin, potentially to stimulate its own movement through the fallopian tube or to support early neural development. The study also confirms that the 8-cell embryo does not produce reproductive steroid hormones—an important finding that suggests hormonal signaling at this stage is likely driven by other pathways.

As seen in previous research on growth factors, the study also showed that the 8-cell embryo tends to produce more hormones than it has receptors for—suggesting that its signals may be directed outward, preparing for interaction with its environment rather than responding internally.

Taken together, these findings reveal a more dynamic picture of early human development—one in which communication, timing, and environmental readiness all play a role. Understanding these early signals could help scientists design better culture systems and may ultimately lead to improved outcomes in both research and clinical care.

Read the publication

As BRF scientists expand their access to research eggs, new findings from the broader scientific community are offering additional insights. One such development is the possible role of zinc in egg activation.

For many years, calcium ions have been known to play an important role in egg activation across many species and have been central to laboratory activation protocols. But recent research suggests that zinc may also be critical — and could offer a significant boost to incubation conditions that support development into continuously dividing parthenote stem cells.

BRF researchers are now working to incorporate this emerging science into future protocols.

On the order of half of the human eggs collected during fertility procedures are not robust enough for reproductive use and are discarded by egg banks. BRF scientists developed a new human egg transport system that makes it possible to rescue and study these otherwise lost eggs for stem cell research.

As egg freezing has become more common, especially among younger donors, the number of eggs collected has grown, along with the number discarded for not meeting clinical standards. Until recently, it was difficult and costly to transport these unfertilized eggs to research laboratories due to their fragility. BRF new transport system marks a significant step forward on the path to universal parthenote stem cells for everybody.

The new Ambient Temperature Transport Medium (ATTM) is so novel and useful that patent protection is now in progress, following submission of a full research report on the findings. For the first time, eggs that could not previously survive transport to a lab can now be safely delivered for research.
This advance allows BRF to study an increased number of human eggs that were previously discarded — turning a lost resource into a vital one. These rescued eggs not only expand the Foundation’s ability to develop parthenote stem cells—an alternative to embryo-derived cells—but also provide valuable insight into human egg maturation more broadly.

Independent Research is in Our DNA

The need for independent research has never been more evident. At the Bedford Research Foundation, the decades-old ban on federally funded stem cell research forced us to forge our own path—one that isn’t tied to federal funding. Now, as the important work of so many of our fellow researchers is hit hard due to massive federal cuts, our laboratory is able to carry foward the mission of basic science.

Organizations reliant on NIH funding often allocate 40-75% to overhead costs like administration and facilities, meaning that only a fraction of your donation directly supports research. For every dollar the NIH distributes, it costs taxpayers about $1.50-1.75, and then only about 60 to 25 cents goes toward research.

In contrast, at Bedford Research Foundation, 96 cents of every dollar you give goes straight toward basic research — research targeting breakthroughs in treating Alzheimer’s, Parkinson’s, neurodegenerative diseases, HIV, blood disorders, and cancers.

We’re proud to hold a four-star rating on Charity Navigator, and we’re home to a pioneering research team, whose visionary work continues to push the boundaries of what’s possible in medical science. Regardless of the political climate, our commitment to solving critical health challenges remains unwavering.

Your support today will make a transformative difference. Join us in funding the research that brings hope and cures to countless lives. You can change the life of everyBODY that you know.

Discover cutting-edge research and innovations in assisted reproduction technology and genetics. The Journal of Assisted Reproduction and Genetics offers the latest insights from reproductive biology to safe ART practices, helping shape the future of fertility treatments and genetic understanding.

Read the Journal of Assisted Reproduction and Genetics here.