Sequestration of bacteria from whole blood by optimized microfluidic cross-flow filtration for Rapid Antimicrobial Susceptibility Testing

•We report a novel, simple microfluidic filter to sequester bacteria from blood.•Single devices removed 97% of red blood cells and retained 30% of bacteria.•Processing with two devices further increased bacterial purity.•The device can provide purified bacteria to other devices in series.

A microfluidic device to separate bacteria from blood cells based on size-exclusion through cross-flow channels was designed and performance tested using fluorescently-labeled, heat-killed Escherichia coli spiked into whole blood. The device is easy and cheap to fabricate, and simply and robustly purifies bacteria from large blood cells. Thus the device would be an effective sample-preparation stage within a point-of-care system for rapid testing for antibacterial resistance.