3D Printed Microfluidic Devices for Integrated Immunoaffinity Extraction, Solid-Phase Extraction, and Fluorescent Labeling of Preterm Birth Biomarkers

A miniaturized, biomarker-based diagnostic for preterm birth (PTB) risk will require multiple sample preparation steps to be integrated in a single platform. To this end, we created a 3D printed microfluidic device that combines immunoaffinity extraction (IAE), solid-phase extraction (SPE), and fluorescent labeling. This device uses an antibody-functionalized IAE monolith to selectively extract PTB biomarkers, a lauryl methacrylate reverse-phase SPE monolith to concentrate and facilitate fluorescent labeling of PTB biomarkers, and 3D printed valves to control flow through the monoliths. The advantageous iterative design process for arriving at a functional device is documented. The IAE/SPE device performed selective, reproducible extractions of three PTB biomarkers from buffer and depleted maternal blood serum, demonstrating its utility for single-biomarker and multiplexed extractions. After tandem extraction and fluorescent labeling, biomarkers eluted from the SPE monolith in a concentrated plug, facilitating future integration with downstream analysis techniques including microchip electrophoresis. This device effectively combines and automates orthogonal chromatographic extraction methods and constitutes a substantial step toward a complete microfluidic PTB prediction platform.