Résumé
This study reports the development of a new micro-machine based flow cytometer with impedance spectroscopy capable of processing cell counting using micro-fluidic technologies and conductivity possible for detection of a single cell level. Micro-scale hydrodynamic focusing is employed to place single cell passing along the center plane of the flow cytometer. By applying AC electrical field, suspended cells are polarized membrane capacitance Cm. cytoplasm conductivity sigma c and cytoplasm permittivity epsilon[c] will vary as a function of frequency. Electrical pulses with frequencies of 3 MHz are fed into the fluidic cell via a pair of silver electrodes. Tracing back the monitored current the number of individual cell species can be evaluated. The changes in the potential difference between the electrodes due to passage of biological cells are measured by a digital storage oscilloscope. Passage of the cells between the electrodes causes change in current frequencies. Frequency shift due to cell passage are measured by calculating Fast Fourier transform of the current signal without and with the cell crossing the gap between the silver electrodes. At a constant flow rate, it was found that the frequency shift is directly proportional to the number of cells. This technique used for the cell counting of human red blood cells [RBC's]. A suspension of RBC's is prepared by taking I ml of the cells and 9 ml of the sucrose buffer [dilution 1:10]. The present cell counting technique is compared with the standard cell counting in order to assess which method was the most feasible and efticient in the laboratory for the counting of red blood cell