Circular shaped microelectrodes for single cell electrical measurements for lab-on-a-chip applications

The impedimetric sensing techniques for single cell characterization have witnessed growing interest due to their high sensitivity and widespread applications. However, adapting the method to different biological measurements in microfluidic environments under various input conditions can result in feeble signal detection leading to a drastic decrease in the sensor sensitivity. The reduced signal-to-noise ratio (SNR) hinders the signal differentiation, sensor accuracy and prohibits fully integrated point-of-care applications. Here, we address the sensitivity enhancement for microfluidic impedimetric sensing of micron and submicron-sized microparticles by exploring novel circular shape electrodes in a simulation study. The influence of radial electrode parameters on differential electrical signal is systematically analyzed in COMSOL Multiphysics using spherical particles ranging from 0.75 µm to 5 µm in diameter. Detailed analysis revealed the strong impact of the circular shape microelectrode geometry and the electrode gap on the signal strength, resulting SNR, and device sensitivity for multiple bioparticles detection. Specifically, ˃ 50 dB improvement in SNR was enabled by optimizing the circular electrode geometrical parameters. Our proposed sensing modality can be adapted for nanoparticles detection by further optimizing the microfluidic device parameters. Graphical abstract: [Figure not available: see fulltext.].