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.