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The physiological pH for human gametes and embryos is generally thought to be between 7.2 and 7.4. In order to maintain this range of pH during culture, i.e. to create a similar environment to that of the human reproductive tract, we use CO₂ gas inside various types of incubators (this blog post by Markus Montag – “Considerations for embryos culture at high altitude”, further explains this).

In vitro, the pH is generally maintained between 7.2 and 7.4.  All Vitrolife media are formulated to meet this narrow pH specification range, supporting optimal metabolic conditions. Maintaining a defined and physiological pH is through the inclusion of certain chemical components in the media called “pH buffers”. These pH buffers act as a weak acid or base. As a result, solutions containing such buffers can resist a change in pH caused by environmental changes.

The most commonly used pH buffer in IVF culture media is bicarbonate, which is the same buffer that is present in our blood. Carbon dioxide (CO2) in the atmosphere surrounding the culture dish will dissolve and equilibrate in the medium. Dissolved CO2 increases the amount of carbonic acid in the medium, releasing protons and therefore decreasing pH in the medium (see equation below). If the CO2 level in an incubator remains constant, the pH of the medium can be maintained.  Vitrolife culture media require a CO2 concentration of 6.0% at sea level, but the CO2 concentration can be adjusted by the end user to reach the desired pH. This ensures there is enough CO2 inside the incubator surrounding the culture dish, and in turn the formation of carbonic acid and protons, to maintain the specified pH of the culture media.

CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+

When a procedure is performed in atmospheric conditions outside of the incubator, the media containing gametes and embryos are exposed to a much lower CO2 concentration (about 0.02%).  This dramatic drop in CO2 concentration will cause a change in the carbonic acid and proton content in the medium and an increase in the pH to a level above what is optimal for gametes and embryo development.  Using an oil overlay on the dish will somewhat delay the effect of this drop in CO2 concentration and subsequent pH increase.  Thus, it is recommended to use media containing a pH buffer other than bicarbonate when performing procedures under atmospheric conditions.

Deepen your knowledge:

Antioxidants, long touted in cosmeceuticals for their anti-aging miracles, and in food industries for their health benefits, are now a new dynamic component in IVF media. While it has been demonstrated that the use of individual antioxidants has beneficial effects, their real power is manifest when used in combination, as is seen in vivo as part of an elegant antioxidant system. This blog post outlines the rationale for including antioxidants in IVF media and how the three antioxidants in the Gx Media system were selected and tested in the mouse model.

The concept of fast freezing or vitrification was first described more than 80 years ago by Basile J. Luyet, the so-called Father of Cryobiology (Luyet, 1937). He showed that supercooled solutions could be solidified without crystallization, forming a glass-like state. Already then, the potential of the technique and the associated challenges were in the research spotlight. Today, we’ve managed to overcome all methodological-related issues of vitrification. It has evolved into a reliable and efficient method to freeze oocytes and embryos. Vitrification is used for medically assisted reproduction and fertility preservation: the goal is to ensure the maximum survival rate with the highest level of biosafety. In this blog post, we will compare closed and open carrier devices for vitrification.

The simple answer is, it can’t. In a well-functioning culture system, the oil should only act as a cover, protecting the gametes and embryos from changes in the environment and potential contaminants. But if the oil quality is sub-optimal, it can decrease embryo development. Most oils are produced from petroleum, which means that embryotoxic components may be present due to the production process and origin of the raw materials.

This year, the annual meeting of ASRM 2021 was back in its physical form, and we where there in-person with a great team from Vitrolife. For those of you who couldn´t attend the meeting or want to update yourself again on the interesting sessions, we have compiled this blog post, with thoughts and reflections from the Vitrolife team on some of the scientific content presented at the meeting.

Introduction

Cryopreservation or cryostorage of gametes and embryos involves storage at ultra-low temperatures (under -140°C). The preservation refers to the ability to maintain cellular functionalities and viability after thawing or warming.

Liquid nitrogen is inert, odorless, colourless, non-corrosive, non-flammable, and extremely cold. It has been the substance of choice for cryostorage in most applications as it achieves temperatures of -196°C (-320°F) when materials are fully submerged.

Why there is a need for the sustainable development goals 

The establishment in 2015 of the Sustainable Development Goals (SDGs) has created a global consensus on the development framework for a better world. However, as we look to the next decade, there is significant cause for concern about the future. The IPCC’s Sixth Assessment report, released in August 2021, confirms that it is indisputable that human influence has warmed the climate system, raising global surface temperature. The report confirms that there is no going back from some changes that are already affecting the climate system. These changes in the climate are widespread, rapid and intensifying and impacts are affecting every region on Earth, including the oceans.

Introduction to Medical Device Regulations - MDR

For 30 years medical devices have been governed by the Medical Device Directive (MDD) implemented in EU/EEA in 1993, and there have been quite a few developments in the field of medical devices since then. For instance, apps used as stand-alone products for different medical purposes have become a reality. The general population has become older, patients are more used to finding medical information on the internet, and the beauty industry uses more advanced and invasive techniques than before. These changes, and more, have prompted an update of the control of medical devices for some time. Eventually, the new Medical Device Regulations (MDR) were developed and came into force on May 26, 2021. From this date, all new medical devices and the manufacturer’s quality management system must comply with the MDR. Implementation deadlines for existing devices are dependent on classification and expiry of existing MDD certificates.

The unique design of SENSE™ provides ideal conditions for optimised oocyte retrieval performance and aspiration time as well as improved patient comfort. Prof William Ledger is Head of Obstetrics & Gynaecology at the University of New South Wales and Director of Reproductive Medicine at The Royal Hospital for Women, Sydney. In this video, Prof Ledger shares his expertise, experience and why he has chosen to use SENSE™ follicle aspiration for all his patients.