In situ analysis of bacterial capture in a microfluidic channel

We present a microfluidic approach for the continuous capture of Salmonella Newport cells suspended in a phosphate buffer using externally applied electric fields. The effects of flow rate, applied electric field and wall shear stress on cell capture in the device are analyzed using particle tracking via fluorescent microscopy techniques. Analyzing capture across multiple locations on the electrode surface enabled the estimation of average capture over the entire electrode area as a function of time. The device exhibits approximately a constant capture rate over an extended time frame, which is verified independently using the cell culture methods. An increased capture rate with an increased electric field is observed. The capture rate dependence on the flow rate and capture rate at various locations with different wall shear stress magnitudes does not exhibit statistically significant variations. The capture trends presented in this study can be utilized for designing microfluidic systems for biosensors, designed bacterial bio-films and devices for bacterial sample concentration from large volumes. (Some figures in this article are in colour only in the electronic version)