Limited cell attachment time as a method to synchronize cells grown in monolayer culture

A novel method of synchronizing monolayer tissue culture cells is described. By limiting the period of attachment of trypsinized cells and the subsequent removal of unattached cells a G1 population of cells is isolated. Evaluation of the degree of synchrony has been carried out by measuring the labeling index and incorporation of [3H]thymidine into DNA. Further conformation of synchrony, as well as a comparison with synchrony by isoleucine deprivation, was obtained by flow cytometry. The expected peak in DNA synthesis rate following limited attachment was observed. This peak becomes more prominent and shifts to earlier times with shorter attachment intervals. The synchronization method described is simple, rapid, yields a substantial number of cells, and is applicable to many cell lines.