Adherent cell cultures are a type of cell culture that requires cells to be attached to a surface in order for growth to occur.[1] Most vertebrate-derived cells (with the exception of hematopoietic cells) are anchorage dependent and require a two-dimensional monolayer to facilitate cell adhesion, spreading and replication.[2] Cell samples can be taken from tissue explants or cell suspension cultures. Adherent cell cultures with an excess of nutrient-containing growth medium will continue to grow until they cover the available surface area.[3] Proteases like trypsin are most commonly used to break the adhesion from the cells to the flask. Alternatively, cell scrapers can be used to mechanically break the adhesion if introducing proteases could damage the cell cultures.[4][5] Unlike suspension cultures, the other main type of cell culture, adherent cultures require regular passaging performed using mechanical or enzymatic dissociation.[1] The culture can be visualized using an inverted microscope, however the growth of adherent cultures is dependent on the available surface area. For this reason, adherent cell cultures are not commonly used to obtain a high yield of cells, instead the use of suspension cultures is preferred.[4]