Cryoprotection—Permeant vs nonpermeant additives

The need for novel cryoprotectants and cryopreservation protocols: Insights into the importance of biophysical investigation and cell permeability

“…[103,104] This information can be used to predict a cell's response to hypo-or hyper-osmotic solutions, the concentration of CPA inside a cell at a given time point, and the concentration/volume of water inside a cell under certain conditions. [105,106] For example, if a given cell type has a low permeability to the CPA, then it will probably require extended incubation in the CPA before freezing to allow adequate penetration, as has been demonstrated previously for glycerol [45] and other CPAs. [12,107]…”

“…[7,19,40,43] CPAs are separated into two broad categories: penetrating and non-penetrating. [7,14,19,40,42,44,45]. Figure 2 shows a schematic representation of cellular responses to these two types of CPAs.…”

An improved technique for the cryopreservation of Onchocerca microfilariae

“…At higher temperatures the toxicity and the permeability to cells increases. Taylor, Adams, Boardman & Wallis (1974) noted this temperature dependence for both permeating and non-permeating additives. These effects were also observed by Miyata (1975) who found that glycerol permeates Trichomonas spp.…”

Cryopreservation and Its Application in Aquaculture

“…Non-permeating cryoprotectants include protein like milk, egg yolk, bovine serum albumin (BSA); sugars such as glucose, sucrose; synthetic polymers like polyethylene glycol and polyvinylpyrrolidone and are believed to stabilize the membrane during cryopreservation [90]. Use of insufficient cryoprotectant before cooling reduces effectiveness, whereas excessive cryoprotectant causes osmotic swelling and rupture during thawing and dilution [91]. Cryoprotectants were found to prevent the formation of ice crystals during freezing [48].…”