A Flow Rate Independent Cell Concentration Measurement Chip Using Electrical Cell Counters Across a Fixed Control Volume

We present a novel method of measuring cell concentration using two electrical cell counters across a fixed control volume. Our device counts cells at the inlet and outlet of a fixed control volume and then measures the cell concentration by calculating the number of cells in the fixed control volume. Previous methods of measuring cell concentration (such as a Coulter counter and a flow cytometer) have attempted to count cells in a given fluid volume or at a known flow rate. Thus, in spite of the miniature nature of previous devices, the accuracy of their results depends on the performance of external mechanisms such as delicate pumps and flow sensors. Our prototype, however, does not depend on accurate fluid measurement or precise control of the flow rate because it measures the number of cells in a fixed control volume. In the experimental study, we measured cell concentrations ranging from $5.8 \times 10^{5}$ to $11.5 \times 10^{5}\ \hbox{cells/mL}$ without measuring or controlling the flow rate. For measuring the cell concentration, our prototype shows a maximum cell concentration measurement error of 10.3%, which is within the error range of a hemacytometer. $\hfill$[2006-0127]