Freezing Media Addition
Freezing Media Addition - Related Videos
01:27
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
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2025
α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition. Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon. Direct addition products are formed faster owing to...
11:17
Fundamental Technical Elements of Freeze-fracture/Freeze-etch in Biological Electron Microscopy
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Cited by 6 •
2014
Basic techniques and refinements of freeze-fracture processing of biological specimens and nanomaterials for examination by transmission electron microscopy are described. This technique is a preferred method for revealing ultrastructural features and specializations of biological membranes and for obtaining ultrastructural level dimensional and spatial data in materials sciences and nanotechnology products.
03:12
Freezing Point Depression and Boiling Point Elevation
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2020
Boiling Point Elevation The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
02:39
Phase Transitions: Melting and Freezing
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2020
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
02:37
Cryopreservation of Murine Brain by Snap Freezing: A Technique to Rapidly Freeze Whole Mouse Brain Specimen for Histological Analysis
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2023
This video demonstrates the cryopreservation of a mouse’s brain to isolate discrete anatomical areas or specific cell populations from the tumor tissues. This technique is critical in obtaining optimal optical resolution of brain tissue morphology for subsequent analysis.
FAQs
Cryoprotectants help limit ice-crystal formation as the sample cools, reducing the physical damage associated with freezing. They also help lessen osmotic and membrane stress as water leaves cells. This protection is important because cellular injury during cooling can reduce viability after thawing and compromise the consistency of later biological experiments.
The freezing medium combines a basal culture solution with cryoprotectants, so both components contribute to preservation. The basal solution supports the sample environment, while cryoprotectants address ice formation and water loss during cooling. Maintaining this combined function helps protect cell lines, primary cells, and other specimens without treating cryoprotection as an isolated step.
Exposure time and cooling rate are important process variables. Samples need controlled contact with the freezing medium, while gradual temperature reduction helps limit stress during the transition to very low temperatures. If these conditions are not handled consistently, post-thaw recovery may vary, making cell banking and repeated experiments less reproducible.
A typical workflow introduces the cryoprotective medium to the biological sample, mixes the components carefully, controls how long the sample remains exposed, and then reduces the temperature gradually before very-low-temperature storage. These steps should be applied consistently across samples. Standardized handling supports comparable preservation outcomes and improves the reliability of later recovery.
This approach is useful when researchers need to preserve viable cell lines, primary cells, or other biological specimens for later use. It supports cell banking, long-term experiments, and studies that require genetically or phenotypically stable samples. Preserving material in advance can also make disease-modeling workflows and repeated experimental designs more consistent.
Careful addition and controlled cooling can improve post-thaw recovery, allowing preserved samples to return to experimental use more reliably. Consistent handling also supports reproducible cell banking and helps maintain genetically or phenotypically stable material over storage. These outcomes are especially valuable when experiments depend on comparable samples across multiple time points or study runs.