Osmolarity effects on observed insect cell size after baculovirus infection are avoided using growth medium for sample dilution

Rates of cell size increase are an important measure of success during the baculovirus infection process. Batch and fed batch cultures sustain large f luctuations in osmolarity that can affect the measured cell volume if this parameter is not considered during the sizing protocol. Where osmolarity di fferences between the sizing diluent and the culture broth exist, biased me asurements of size are obtained as a result of the cell osmometer response. Spodoptera frugiperda (Sf9) cells are highly sensitive to volume change wh en subjected to a change in osmolarity. Use of the modified protocol with c ulture supernatants for sample dilution prior to sizing removed the observe d error during measurement.