The apoptosis of cells is one of the fields that attract increasing attention in biology today.Usually,the cells are treated with chemicals when detecting apoptosis.It is highly desired to detect apoptosis in a real-time basis.Apoptosis of Jurkat cells was studied using a real-time electrorotation chip.This chip allows the detection of the cell membrane capacitance changes during the course of apoptosis and therefore facilitates the analysis of apoptosis in a real-time basis without involving any chemical treatment.