Hollow AFM cantilever pipette

• A transparent hollow AFM cantilever of 153.5 μm long, 3.7 μm wide and 2.2 μm thick is fabricated.
• Microfluidic interface is made between the chip and the syringe pump.
• The pipetting (dispense and aspirate) function using a hollow AFM is demonstrated.
• For a 2 μm aperture a hydrodynamic resistance of 1.5 × 1017 Pa-s/m3 was obtained.
• A minimum flow rate of 5 fL/s is achieved.

Hollow atomic force microscope (AFM) cantilevers were used earlier to dispense liquids of sub 100 nm diameter and inject reagents into one single cell. However, aspiration of liquid was never shown. In this work, we demonstrate pipetting (dispensing and aspiration) of liquid using hollow AFM cantilevers. The microfabricated 155 μm long cantilever had a volume capacity of 2.64 pL, with pipetting flow rate control of 5 fL/s. This functionality enables to move liquid matter at nanoscale, do force-spectroscopy and imaging with the same AFM.

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