Harvesting and subculturing cells growing on denatured-collagen coated microcarriers (Cytodex 3).

Selecting correct procedures and conditions for harvesting cells was essential for successful subcultivation of cells when using the microcarrier culture technique. The proteolytic enzymes trypsin, Dispase and collagenase were compared with respect to the yield and the viability of Vero cells when harvested from Cytodex 3 microcarriers. Treatment with Dispase or trypsin resulted in similar viabilities but recovery after trypsin treatment was improved. The advantage of using collagenase was the improved plating efficiency of cells when subculturing to new microcarrier cultures. Pre-washing the confluent microcarriers with EDTA (0.02% w/v) improved the yield and the viability when harvesting with trypsin or collagenase. The stage of the culture cycle when cells were harvested did not influence relative recovery or viability. In contrast, significant differences in recovery and viability were found when harvesting cells grown in the presence of different batches of foetal calf serum. The results confirm that the choice of enzyme for harvesting depends upon the cell type and purpose of the culture.