Estimation of Analyte's Vertical Positions above the Surface of Nanocapacitor Array Biosensors

A novel method is proposed to estimate the vertical position of analytes above the surface of nanoelectrode array biosensors, which monitor the capacitance fluctuations caused by analytes in a microfluidic channel. The position estimation method, which takes advantage of accurate physics-based numerical simulations and simple analytical models, is tested on measurements of polystyrene nanoparticles (NPs) with an advanced high frequency impedance spectroscopy platform equipped with a new and optimized microfluidic chamber. The NP height estimation is directly validated on physics-based numerical simulations. In addition, it is indirectly confirmed by showing that numerical simulations with random NP positions (in agreement with the experimental height distribution) yield response distributions closely matching their measured counterpart.