The bacterialconcentration was adju

The bacterialconcentration was adjusted to a desired level, a certainamount of AF-MNPs suspended in PBS (10 mg mL-1) wasthen added into the bacterial solution, and the solutionvolume was fixed to 5 mL. The solution was incubated by arotary shaker at 250 rpm for a specific period (when capturekinetics of E.coli in static state was evaluated, the suspensionwas allowed to settle for a specific period), then an externalmagnet was employed for magnetic separation. The supernatant was then carefully pipetted into a cell to measure itsOD600using absorption spectroscopy. The relative efficienciesof the magnetic capture of bacteria by AF-MNPs werecalculated from the decrease of turbidity relative to a referencebefore magnetic capture (9, 11).