Predicting the behavior of microfluidic circuits made from discrete elements

Abstract

Microfluidic devices can be used to execute a variety of continuous flow analytical and synthetic chemistry protocols with a great degree of precision. The growing availability of additive manufacturing has enabled the design of microfluidic devices with new functionality and complexity. However, these devices are prone to larger manufacturing variation than is typical of those made with micromachining or soft lithography. In this report, we demonstrate a design-for-manufacturing workflow that addresses performance variation at the microfluidic element and circuit level, in context of mass-manufacturing and additive manufacturing. Our approach relies on discrete microfluidic elements that are characterized by their terminal hydraulic resistance and associated tolerance. Network analysis is employed to construct simple analytical design rules for model microfluidic circuits. Monte Carlo analysis is employed at both the individual element and circuit level to establish expected performance metrics for several specific circuit configurations. A protocol based on osmometry is used to experimentally probe mixing behavior in circuits in order to validate these approaches. The overall workflow is applied to two application circuits with immediate use at on the bench-top: series and parallel mixing circuits that are modularly programmable, virtually predictable, highly precise, and operable by hand.

Assessment of the biocompatibility of three-dimensional-printed polymers using multispecies toxicity tests

“…[6][7][8][9][10][11] In this regard, biocompatibility of currently available 3D printed polymers is critical for any biological and biomedical applications. 10,11 Bioassays on living cells and tissues are conducted in aqueous media.…”

3D Printing of Compositional Gradients Using the Microfluidic Circuit Analogy

“…We use a model based on the microfluidic circuit analogy to determine the correct ink dispensing profiles required for multimaterial printing. The MCA model has already been thoroughly discussed and used in several other applications, thus its derivations are outside of the scope of this manuscript . Briefly, several components of a DIW printing system have direct analogs with electronic circuit systems ( Table 1 ).…”

Modular, Discrete Micromixer Elements Fabricated by 3D Printing

“…For example, in the processes used to construct devices presented in this report, tolerances can be as high as 30 µm, whereas micro CNC tolerances are often < 5 µm and semiconductor processing tolerances are submicron [14]. Variation in channel sizes in discrete microfluidic elements directly propagate fluid handling performance errors, implying the need for simple and versatile empirical device characterization methods.…”

“…The discrete microfluidic elements used in this study were manufactured using stereolithography from DSM Somos Watershed XC 11122 photoresin in the manner previously reported [13][14][15][16]18]. Microfluidic channels for all components were designed with 642.5 µm x 642.5 µm square cross sections, in keeping with the previously established standards.2 Test assemblies as shown in Figure 2 were assembled by hand, with special care taken to correctly orient L1 devices such that inlet streams were correctly split and recombined to enhance mixing as described in Section 2.1.…”

“…Both lamination and chaotic advection ultimately require the construction of multi-layer channel devices with three-dimensional features, a significant challenge for microfabrication technologies. Previously, we introduced a system of discrete elements for assembling three-dimensional microfluidic circuits with integrated process sensors [13][14][15][16]. We leveraged additive manufacturing techniques (i.e.…”