A label-free high throughput resistive-pulse sensor for simultaneous differentiation and measurement of multiple particle-laden analytes

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We describe an all-electronic, label-free, resistive-pulse sensor that utilizes multiple microchannels for parallel detection, counting and differentiation of multiple biological particles simultaneously. Four particle solutions, including 20 µm and 40 µm polymethacrylate particles, Juniper Scopulorum (Rocky Mountain Juniper) pollen and Populus deltidoes (Eastern Cottonwood) pollen, were loaded to the four peripheral reservoirs, respectively, and were driven to the central reservoir through four microchannels, all operating simultaneously for particle detection and counting. Experiments demonstrated that this sensor was able to differentiate and count multiple particle solutions simultaneously through its four microchannels fabricated on polymer membranes. Thus the sensing throughput has been improved significantly in contrast to typical Coulter counters without sacrificing accuracy, sensitivity and reliability. Furthermore, the experimental results also proved the feasibility of differentiating various pollens from polymethacrylate microparticles with the multi-channel resistive-pulse sensor. The differentiation is based on difference in size and surface charge for the bioparticles, with no need for labeling of samples. Possible improvements and extensions to other biological particle detection are discussed.