Code-division multiplexed resistive pulse sensor networks for spatio-temporal detection of particles in microfluidic devices

Abstract

multidimensional information on spatio-temporal manipulation of particles in a microfluidic chip into a decodable electrical time waveform.Here, we enhance the multiplexing capacity of the Microfluidic CODES platform by employing sensors designed to produce unipolar, non-orthogonal sequences, rather than specially designed bipolar orthogonal Gold sequences we used earlier. We also introduce a decoding algorithm that combines machine learning techniques with minimum mean-squared error (MMSE) estimation to decode sensor signals. As a proof of principle, we developed a microfluidic device with a network of 10 code-multiplexed sensors and characterized it using a suspension of cells in phosphate buffer saline (PBS) solution. Figure 1: (a) An image of the fabricated microfluidic device with 10 code-multiplexed sensors. Each sensor consists of a pre-coding sensor followed by a 5-bit coding section. (b) A close-up of the sensor designed to generate code "10011". DEVICE DESIGNOur code-multiplexed sensor network is formed by three micromachined coplanar surface electrodes aligned with microfluidic channels (Figure 1a). Each sensor in the network is made up of multiple pairs of 10 μm-wide electrode fingers arranged in a distinct pattern. Across the sensor network, the current flow is confined to sections of the microfluidic channels that fall in between different electrodes. Therefore, only when particles occupy these