Petersson, Filip, et al. Analytical chemistry, 2007, 79(14), 5117-5123.
The free-flow acoustophoresis (FFA) method can continuously separate mixed particle suspensions into multiple outlet fractions and is suitable for both biological and non-biological suspended particles.
Construction of FFA equipment, sample collection and flow rate control
· The particle separation chips for free-flow acoustophoresis (FFA) were fabricated using silicon microfabrication techniques, with flow channels etched into silicon wafers and sealed with boron silica glass lids. Fluid inlets and outlets were attached using silicon tubing.
· Twelve-port injectors were used to acquire samples from the outlets. PTFE tubing (0.3-mm i.d.), inserted in the silicone tubing, connected the chip and the injectors. Each injector collected samples from two outlets in 100-µL PTFE tubing (0.8-mm i.d.) loops.
· Flow rate control: Syringe pumps were utilized to regulate the flow rates within the chip. Each outlet was linked separately to high-precision glass syringes through injectors with Teflon tubing, enabling autonomous control over the flow rates of the outlets. The inlet for the clean fluid was attached to a syringe pump, while the inlet for the particle suspension was connected to a 50-mm-long piece of PTFE tubing (0.3-mm i.d.), with one end submerged in a beaker where the sample suspension was drawn in at a rate determined by the disparity between the net outlet flow and the clean fluid inlet flow.
