Figure 2.

A. Typical implementation of microfluidic RPS. A fluidic channel (blue), typically a PDMS mold, is bonded to a substrate containing microfabricated electrodes (orange). A voltage is applied across the channel while the current is monitored. A cell’s presence in the channel causes a current drop. B. Example of a multichannel RPS design using eight detection channels to improve throughput by multiplexing. Reprinted with permission from (Saleh, 2003) C. NPS, a variation of RPS, is used to measure five surface markers in one channel. Each section is functionalized with an antibody, and cells expressing the corresponding surface marker traverses that section more slowly. Adapted with permission from (Balakrishnan et al., 2015). Further permissions related to the material excerpted should be directed to the ACS. D. Schematic and electrical model of a constriction channel design for microfluidic EIC. Cells flow through the constriction channel while impedance and elongation are measured continuously. Two-frequency data at 1 kHz and 100 kHz allow calculation of specific membrane capacitance and cytoplasm conductivity. Adapted with permission from (Y. Zhao et al., 2014)