Manufacturing and wetting low-cost microfluidic cell separation devices

Biomicrofluidics (Impact Factor: 3.36). 09/2013; 7:056501. DOI: 10.1063/1.4821315


Deterministic lateral displacement (DLD) is a microfluidic size-based particle separation or filter technology with applications in cell separation and enrichment. Currently, there are no cost-effective manufacturing methods for this promising microfluidic technology. In this fabrication paper, however, we develop a simple, yet robust protocol for thermoplastic DLD devices using regulatory-approved materials and biocompatible methods. The final standalone device allowed for volumetric flow rates of 660 ll min À1 while reducing the manufacturing time to <1 h. Optical profilometry and image analysis were employed to assess manufacturing accuracy and precision; the average replicated post height was 0.48% less than the average post height on the master mold and the average replicated array pitch was 1.1% less than the original design with replicated posts heights of 62.

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Available from: Ryan S Pawell
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    ABSTRACT: [This corrects the article on p. 056501 in vol. 7.].
    Full-text · Article · Sep 2013 · Biomicrofluidics
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    ABSTRACT: Microfluidic particle separation technologies are useful for enriching rare cell populations for academic and clinical purposes. In order to separate particles based on size, deterministic lateral displacement (DLD) arrays are designed assuming that the flow profile between posts is parabolic or shifted parabolic (depending on post geometry). The design process also assumes the shape of the normalized flow profile is speed-invariant. The work presented here shows flow profile shapes vary, in arrays with circular and triangular posts, from this assumption at practical flow rates (10 < Re < 100). The root-mean-square error (RMSE) of this assumption in the circular post arrays peaked at 0.144. The RMSE in the triangular post array peaked at 0.136. Flow development occurred more rapidly in circular post arrays when compared to triangular post arrays. Additionally, the changes in critical bumping diameter (DCB) the DLD design metric used to calculate the size-based separation threshold were examined for 10 different row shift fractions (FRS). These errors correspond to a DCB that varies as much as 11.7% in the circular post arrays and 15.1% in the triangular post arrays.
    Full-text · Conference Paper · Dec 2013
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    ABSTRACT: Micropost arrays serve as a plaform for the next generation of diagnostic devices. These arrays are found in microfluidic devices for peripheral blood-based diagnostics and metastatic cancer management. The function and performance of these devices is determined by the underlying micro-scale fluid mechanics. Typically, these devices operate in the creeping regime (Re << 1) where the viscous forces of the fluids dominate. Recent advances in manufacturing allow for higher Reynolds number flows (Re >> 1) where the inertial forces dominate. In this work, we use computational simulations to show there is a transitional region (1 < Re < 20) in between the laminar and creeping regimes for two different micropost array geometries. Numerical analysis is employed to investigate jet formation both within the array and at the array exit. The peak-to-peak amplitude of the streamwise normalized velocity profile is used to quantify jet formation within the array; the streamwise velocity profile at the end of the array exit is used to determine jet length at the exit of the array. Above the transitional region (Re > 20) significant jets form downstream of the posts, amplitude scales exponentially and jet length scales with Re according to power law.
    Full-text · Article · May 2014
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