Medium for freezing human embryos

EmbryoFreeze™ and EmbryoThaw™ media are PBS/propanediol based cell culture media for freezing and thawing human embryos. These media can be used with 2PN up to 4-cell stage human embryos.

3 types of kits are available:

  • a one step freezing / 3 step thawing complete kit
  • a three step thawing only kit
  • a one step freezing only kit

EmbryoFreeze/Thaw are CE marked as Class III medical devices according to EU directive 93/42/EEC.

EmbryoFreeze/Thaw complies with the following specifications:

pH 7.2-7.4
Osmolality EmbryoThaw 3 530-560mOsm/kg
Sterility Sterile
Endotoxine < 0.25 EU/mL
 Mouse embryo assay ≥ 80% blastocysts after 96h incubation
Shelflife 18 months from date of produce
Albumin FDA (USA) and EMEA (Europe) compliant

Product order codes

EMF30_P EmbryoFreeze/Thaw with propanediol - 30 procedures
EMF40_T_P EmbryoThaw with propanediol - 40 procedures
EMF120_F_P EmbryoFreeze with propanediol - 120 procedures

The product composition can be found in the MSDS (see Resources). Additional information on some components is provided below:

Component Benefit

Generally, in the first years of slow freezing, DMSO was used for cryoprotection. Indeed, early cleavage stage embryos can be frozen in either 1,2-propanediol (PROH) and DMSO, both returning comparable satisfactory results (Shaw, et al. 2000). Nowadays, DMSO is successfully replaced by PROH because of lower toxicity. Thus, in most cases, with very few exceptions, a combination PROH and sucrose is used for the cryopreservation of early embryos (Mandelbaum and Ménézo 2001) (Veeck, et al. 2009).

PROH can readily permeate cell membranes and establish hydrogen bonds with water molecules to prevent ice crystallization. Consequently, PROH causes a slight lowering of the freezing point of the solution. Also, during freezing, the free water solidifies into ice and remaining solution will contain progressively higher concentration of electrolytes, reaching their toxicity level. The cryoprotective agent has the ability to reduce toxic effects of high concentrations of solutes, including salts. The protection may originate from the ability of PROH to replace water molecules around compounds, such as enzymes, hereby protecting them from irreversible conformational changes, which may occur at high salt concentrations (Chang, et al. 2010).

Macromolecules (HSA and sucrose(20 mM))

Cryoprotective solutions have been supplemented with macromolecules such as sucrose and human serum albumin (HSA). Several studies have shown that such molecules help to reduce physical damage and help to maintain osmotic pressure of the extracellular fluid (Shaw et al. 2000).

Besides its cryoprotective role, HSA facilitates gamete or embryo manipulation by preventing adsorption to the surface of petri dishes and pipettes through saturation of the potential binding sites.
Also, the increased viscosity of the media, caused by the addition of HSA, promotes the ease of embryo handling and manipulation (Trounson and Gardner 2000).

Literature concerning the components

     Chang, C, L Sung, C Lin, H Kort, X Yang, and X Tian, The oocyte spindle is preserved by 1,2-propanediol during slow freezing., Fertility and Sterility (2010),Vol.93,pp.1430-9
     Mandelbaum, J, and Ménézo, Embryos cryopreservation in humans, In A comprehensive textbook of assisted reproductive technology: laboratory and clinical perspective, by D Gardner, A Weissman and C. Howles. New York: Academic Press (2001)
     Shaw JM, Oranratnachai A, Trounson AO., Fundamental cryobiology of mammalian oocytes and ovarian tissue., Theriogenology (2000),Vol.53,pp.59-72
     Trounson AO, and Gardner, DK., , Handbook of in vitro Fertilization, Boca Raton, Florida: CRC Press (2000),Vol.2
     Veeck Gosden, L, R Berrios, R Bodine, R Clarke, and Zaninovic., The human embryo: slow freezing., In Textbook of Assisted Reproductive Technologies: Laboratory and Clinical Perspectives, by D Gardner, A Weissman, C Howles and Z Shoham. London, U.K.: Informa Healthcare (2009),pp.275-587


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