Design and fabrication of a 3D printed acoustofluidic micropump for biomedical and lab-on-chip applications

This thesis reports the design, additive manufacture and experimental validation of a valve-free, nozzle–diffuser acoustofluidic micropump produced entirely on a desktop fused-deposition modelling (FDM) printer. The pump body is printed in PLA at 100 % infill; a commercially available 20 mm-diameter mist-maker transducer (113 kHz) is epoxied into the housing, its stainless-steel membrane bearing manufacturer-drilled conical apertures (6 μm on the nozzle side, 50 μm on the diffuser side) that rectify acoustic streaming. Particle-tracking velocimetry in a 0.5 mm × 0.5 mm glass capillary shows that net flow begins at ≈ 5–6 V and increases almost linearly to 515 μL min⁻¹ at 12 V, drawing 1.80 W of electrical power. Continuous operation at 12 V for 20 min shows no drift in current. Leak-testing under a small static head confirms a watertight epoxy seal, and passive back-flow blocking is observed when power is removed. Size-selective capability was demonstrated using a mixture of 5 μm and 20–40 μm polystyrene beads; after three minutes of pumping at 12 V, no large beads were detected in the outlet, indicating complete retention of the 20–40 μm fraction. Combining half-milliliter-per-minute throughput with sub-2 W power, print-and-assemble time under three hours and zero high-voltage electronics, the device offers a low-cost, easily replicable pumping element for battery-powered point-of-care diagnostics, environmental sampling and wearable drug-delivery platforms.