For which application is density gradient centrifugation most commonly utilized?

Density gradient centrifugation is primarily utilized for the isolation of mononuclear cells, such as lymphocytes and monocytes, from blood or other biological fluids. This technique separates cells based on their density by spinning samples in a centrifuge that creates a gradient. Cells with lower density, like mononuclear cells, will migrate to a different layer in the gradient compared to denser cells, such as granulocytes and erythrocytes.

This method is particularly important in cytometry and immunology for obtaining high-purity populations of specific cell types for further analysis or experiments. The effectiveness of density gradient centrifugation makes it a standard procedure in various laboratories focusing on immunological studies, cancer research, and cell-based therapies.

The other options, while important in laboratory practices, do not typically involve density gradient centrifugation as a primary method for their respective applications.