Detection limits in nanomechanical mass flow sensing for nanofluidics with nanowire open channels

Nanomechanical sensing is applied to measure the transport of liquid along the external surface of nanowire open fluidic channels. We integrate nanowire open channels with microcantilever resonators as sensors, enabling larger flow measurements; or use the nanowires simultaneously as open channels and resonators, for quantifying extremely small amounts of liquid. We study the detection limits of both systems and their implications for measuring the transport of ionic liquid from a microdroplet reservoir to Si nanowires when these are partially inserted into the microdroplet in the absence of any electrical signal. We obtain detection limits in the order of tens of femtogram and single attograms for each system, respectively, and a combined sensing range from 1 ag to beyond 10 pg, enabling the detection of transport of liquid volumes down to the zeptoliter scale.