Electrorotation studies of baby hamster kidney fibroblasts infected with herpes simplex virus type 1

The dielectric properties of baby hamster kidney fibroblast (BHK(C-13)) cel ls have been measured using electrorotation before and after infection with herpes simplex virus type 1 (HSV-I). The dielectric properties and morphol ogy of the cells were investigated as a function of time after infection. T he mean specific capacitance of the uninfected cells was 2.0 mu F/cm(2), re ducing to a value of 7.5 mu F/cm(2) at 12 h after infection. This change wa s interpreted as arising from changes in the cell membrane morphology coupl ed with alterations in the composition of the cell membrane as infection pr ogressed. The measured changes in the cell capacitance were correlated with alterations in cellular morphology determined from scanning electron micro scope (SEM) images. Between 9 and 12 h after infection the internal permitt ivity of the cell exhibited a rapid change, reducing in value from 75 epsil on(o) to 58 epsilon(o), which can be correlated with the generation of larg e numbers of Golgi-derived membrane vesicles and enveloped Viral capsids. T he data are discussed in relation to the known life cycle of HSV-I and indi cate that electrorotation can be used to observe dynamic changes in both th e dielectric and morphological properties of virus-infected cells. Calculat ions of the dielectrophoretic spectrum of uninfected and infected cells hav e been performed, and the results show that cells in the two states could b e separated using appropriate frequencies and electrode arrays.