Microfluidic multipoles: theory and applications

TL;DR

This paper introduces exact models for mass transport in microfluidic multipoles using conformal mapping, validated experimentally, enabling advanced design and applications like reconfigurable devices and automated assays.

Contribution

It provides the first exact solutions for mass transport in MFMs, facilitating improved design and novel applications in open-space microfluidics.

Findings

Models validated with 3D printed devices

Reconfigurable MFMs for surface processing

Automated immunoassay demonstration

Abstract

Microfluidic multipoles (MFMs) have been realized experimentally and hold promise for "open-space" biological and chemical surface processing. Whereas convective flow can readily be predicted using hydraulic-electrical analogies, the design of advanced MFMs is constrained by the lack of simple, accurate models to predict mass transport within them. In this work, we introduce the first exact solutions to mass transport in multipolar microfluidics based on the iterative conformal mapping of 2D advection-diffusion around a simple edge into dipoles and multipolar geometries, revealing a rich landscape of transport modes. The models were validated experimentally with a library of 3D printed MFM devices and found in excellent agreement. Following a theory-guided design approach, we further ideated and fabricated two new classes of spatiotemporally reconfigurable MFM devices that are used for processing surfaces with time-varying reagent streams, and to realize a multistep automated immunoassay. Overall, the results set the foundations for exploring, developing, and applying open-space MFMs.