Portable histone assay technology (PHAST) for the sample-to-answer detection of circulating histones in whole blood

Circulating histones are a potential biomarker for organ failure, organ transplant rejection, and sepsis. There is a need for point-of-care detection of histones in patient samples to enable diagnostics in the emergency department (sepsis), military field hospitals (trauma-induced organ failure), and at home (transplant rejection). For these applications, it is necessary to detect histones directly from whole blood samples without any intermediate steps and with low-cost portable instrumentation. Here we introduce portable histone assay technology (PHAST), an assay and a low-cost handheld instrument for the sample-to-answer detection of histones directly from blood samples. The assay utilizes a DNA-based FRET reporter molecule to enable direct detection of histones in a single step, while anti-red-blood-cell magnetic beads in combination with a moveable magnet in the handheld instrument remove the red blood cells prior to the fluorescence measurement. Using this novel approach, we detect clinically relevant concentrations of histones spiked into whole blood in under 20 min.