3D Flow Field Measurements Outside Nanopores

TL;DR

This paper introduces a non-stereoscopic, video-based particle tracking method using optical tweezers and Quadrant Interpolation to measure 3D fluid flow around nanopores, revealing polarity-dependent flow patterns.

Contribution

It presents a novel 3D flow measurement technique around nanopores that allows for automated mapping and analysis of flow fields in relation to nanopore orientation.

Findings

Flow fields depend on nanopore polarity.

The method enables 3D mapping of voltage-driven flows.

Flow behavior aligns with existing models of nanopore flow dynamics.

Abstract

We demonstrate a non-stereoscopic, video-based particle tracking system with optical tweezers to study fluid flow in 3D in the vicinity of glass nanopores. In particular, we used the Quadrant Interpolation algorithm to extend our video-based particle tracking to displacements out of the trapping plane of the tweezers. This permitted the study of flow from nanopores oriented at an angle to the trapping plane, enabling the mounting of nanopores on a micromanipulator with which it was then possible to automate the mapping procedure. Mapping of voltage driven flow in 3D volumes outside nanopores revealed polarity dependent flow fields. This is in agreement with the model of voltage driven flow in conical nanopores depending on the interaction of distinct flows within the nanopore and along the outer walls.