Dimethyl sulfoxide (DMSO) is a small organic molecule with the chemical formula (CH₃)₂SO. This colorless liquid is widely utilized in cell culture. Its unique chemical properties, including its ability to dissolve a broad range of substances and penetrate biological membranes, make it a valuable tool. DMSO’s significance in cell culture stems from its diverse applications, supporting various experimental needs and long-term cell preservation strategies.
Primary Role in Cell Cryopreservation
One widespread use of DMSO in cell culture is its role in cryopreservation, the process of preserving cells by cooling them to very low temperatures for long-term storage. Freezing biological samples without cryoprotectants causes significant damage to cells due to ice crystal formation. These crystals can rupture cell membranes and organelles, leading to cell death upon thawing.
DMSO acts as a cryoprotectant by penetrating cell membranes and helping to prevent large, damaging intracellular ice crystals. It achieves this by lowering the freezing point of solutions and promoting the formation of a glassy, amorphous solid state (vitrification) rather than crystalline ice. This mechanism reduces cellular damage, allowing cells to remain viable after freezing and subsequent thawing. Typical concentrations of DMSO for cryopreservation range from 5% to 10%, often combined with saline or serum albumin in the freezing medium. The specific concentration chosen can vary depending on the cell type to optimize cell survival.
DMSO as a Solvent and Delivery Agent
Beyond cryopreservation, DMSO serves as a widely used solvent for various compounds in cell culture. Its amphipathic nature, meaning it possesses both polar and non-polar characteristics, allows it to dissolve substances poorly soluble in water. This property makes it suitable for preparing concentrated stock solutions of many drugs, stains, hormones, and small molecules.
Researchers often dissolve these compounds in concentrated DMSO to create a stock solution, which is then diluted into aqueous cell culture media. DMSO can also enhance the permeability of cell membranes, assisting in the delivery of these dissolved compounds into the cells, although its primary function in this context is as a solvent.
Safe Handling and Cellular Considerations
While DMSO offers significant benefits, its use in cell culture requires careful consideration due to its potential cellular toxicity. The degree of toxicity depends on the concentration of DMSO used and can vary significantly among different cell types. For instance, some cell lines can tolerate up to 0.5% or even 1% DMSO without severe cytotoxicity, whereas primary cell cultures may be more sensitive and require concentrations below 0.1%. Concentrations exceeding 5% can cause substantial cell death by disrupting cell membranes.
To minimize negative effects, it is important to use high-purity, cell culture-grade DMSO to avoid introducing contaminants that could harm cells. Personal safety precautions are also necessary when handling DMSO. It can rapidly penetrate skin and carry dissolved substances into the body, necessitating the use of appropriate personal protective equipment such as chemical-resistant gloves, lab coats, and eye protection. Handling DMSO in a well-ventilated area or chemical fume hood is advisable to prevent inhalation of vapors.