Surface area and anchorage-dependent growth of Chinese hamster ovary cells

Cell growth can be affected by many factors. For study of the cell responses under various environmental changes, the traditional method using batch cultures may not provide precise answers. It sometimes even leads to misapprehension. A flow system was therefore designed to eliminate the variations in chemical environment during the cell growth. An anchorage Chinese hamster ovary (CHO) cell line was chosen for study under this system. With the help of time-lapse video recording and image analysis, it was found that the exposed surface area (Ae) of Chinese hamster ovary (CHO) cells was significantly affected by the serum concentration (S) in the medium. Cells appeared to be larger when cultivated in medium of low serum content. Comparing the growth rates of cells on different substrata, we have found that, although they were different at a given serum concentration, the growth curves could be correlated to a Monod type equation by replacing the substrate term with AeS. Furthermore, when we studied the effect of density-dependent inhibition of cell growth, we found that there exists a minimum value of AeS required for stimulating cell proliferation. Once AeS falls below this value, cell proliferation stops. These observations seemed to indicate that the interaction between serum factors and cell surface, i.e., AeS, is an important parameter of the growth of CHO cells.