Optimized Creation of Monolayers for Parallel Readout of Bead-Based Assays

Abstract

This publication presents the basic studies and the design optimization process of a microfluidic aggregation chamber in order to achieve highly periodical and mechanically stable monolayers of beads. All investigated designs of microfluidic devices exhibit one inlet channel connected to the so-called aggregation chamber. This chamber measures a depth which only slightly exceeds the diameter of the beads and possesses several outlet channels. With depths of the outlets smaller than a bead diameter, the beads are kept back and forced to accumulate inside the aggregation chamber as a mono-layer. CFD-simulations are carried out to describe the process of filling and to assist the process of design optimization.

Benchmarking different chamber and outlet designs, we found an optimum filling behavior for a rhombus-like aggregation chamber connected to a single outlet channel at the same width as the chamber. Here, the aperture angle 60° fosters hexagonal aggregation patterns which leads to the highest packaging density. Reproducible filling ratios of more than 94% have been achieved.