Fig. 2. Bacterial isolation from blood by smart centrifugation.

a Illustration of liquid and cell movement. The left and right tubes illustrate the positions of sample liquid, density medium, red blood cells and bacteria before and after smart centrifugation. The middle graph qualitatively illustrates the trajectories (solid lines) of bacteria (green) and red blood cells (red) during centrifugation, from a mixed state (left brackets) to a separated state (right brackets). The slopes of the lines are the particle sedimentation speeds, v_RBC and v_bac, and liquid interface, v_int, and sedimentation interface velocity, v_sed, derived in SI. b Blood cell removal efficiency, meaning the fraction of blood cells removed from the supernatant after centrifugation relative to the initial number of blood cells in the sample (n=3). c Bacterial isolation efficiency, meaning the number of colony-forming units in the supernatant after centrifugation relative to the initial number of colony-forming units in the spiked sample. Bar heights are mean; error bars are sd; n.s. and *** indicate significance levels p > 0.05 and p ≤ 0.001, respectively; the bacterial concentration C refers to the CFU /ml in the blood sample. Each data point corresponds to an individual experiment. A total of n = 70 samples were tested. The figures were created and edited using the open-source software Inkscape (a) and MATLAB R2021 (b) and (c).