Cells in suspension may attach to one another and form clumps for a variety of reasons. The most common cause of cell clumping is the presence of free DNA and cell debris in the culture medium, which occurs following cell lysis. The sticky nature of DNA causes cells and other debris to aggregate into large clumps. Below are some causes of cell lysis and DNA release into culture media.
Cell clumping reduces access to critical nutrients and, as a result, hinders overall cell growth. Additionally, cell clumps compromise downstream assays that require clean preparation of single cells (e.g., flow cytometry). Depending on the underlying cause of clumping, we suggest solutions for its prevention in the table below.