Nano-NMR based flow meter

Abstract

Microfludic channels are now a well established platform for many purposes, including bio-medical research and Lab on a Chip applications. However, the nature of flow within these channels is still unclear. There is evidence that the mean drift velocity in these channels deviates from the regular Navier-Stokes solution with `no slip' boundary conditions. Understanding these effects, is not only of value for fundamental fluid mechanics interest, but it also has practical importance for the future development of microfluidic and nanofludic infrastructures. We propose a nano-NMR based setup for measuring the drift velocity near the surface of a microfludic channel in a non-intrusive fashion. We discuss different possible protocols, and provide a detailed analysis of the measurement's sensitivity in each case. We show that the nano-NMR scheme outperforms current fluorescence based techniques.

Changes in current version: page 1, added references for classic NMR velocity measurement. page 3, edited figure 3. page 4, added references on non-Lorentzian spectrum measured in another platform. page 5, updated figure 5 and changed summary. supplementary material - revised to include new results