Detecting particles flowing through interdigitated 3D microelectrodes.
Counting cells in a large microchannel remains challenging and is particularly critical for in vitro assays, such as cell adhesion assays. This paper addresses this issue, by presenting the development of interdigitated three-dimensional electrodes, which are fabricated around passivated pillarshaped silicon microstructures, to detect particles in a flow. The arrays of micropillars occupy the entire channel height and detect the passage of the particle through their gaps by monitoring changes in the electrical resistance. Impedance measurements were employed in order to characterize the electrical equivalent model of the system and to detect the passage of particles in real-time. Three different geometrical micropillar configurations were evaluated and numerical simulations that supported the experimental activity were used to characterize the sensitive volume in the channel. Moreover, the signal-to-noise-ratio related to the passage of a single particle through an array was plotted as a function of the dimension and number of micropillars.
Swiss Federal Institute of Technology, Lausanue EPFL, Switzerland. elena.bianchi@epfl.ch
Elena
E
Bianchi
Enrica
E
Rollo
Samuel
S
Kilchenmann
Francesco M
FM
Bellati
Enrico
E
Accastelli
Carlotta
C
Guiducci
D002452:Cell Count / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005434:Flow Cytometry / Q000295:instrumentation*; D008839:Microelectrodes; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*