Presentation: 2025 ND EPSCoR Annual conference 

October 21, 2025, NDSU Memorial Union, Fargo, North Dakota

Nanofabricated Deterministic Lateral Displacement Arrays for Biomarker Isolation from Whole Blood

This research presents the development of a microfluidic lab-on-a-chip platform for the efficient isolation of disease biomarkers, such as extracellular vesicles, directly from unprocessed whole blood. Our approach is centered on deterministic lateral displacement (DLD), a technique that separates particles by size as they flow through an array of micro- or nano-scale obstacles. Particles larger than a critical diameter are laterally displaced, while smaller particles follow a zigzag path, enabling continuous and label-free separation. We designed and fabricated various DLD structures on 4-inch silicon wafers, employing electron beam lithography and a maskless aligner to create high-precision silicon nanopost arrays. These arrays feature post diameters ranging from 300−600 nm, achieving critical separation diameters of 100−350 nm. The devices were sealed by anodically bonding a transparent silica cap containing drilled inlet and outlet ports. Preliminary validation using fluorescent particles smaller than the critical diameter confirmed the predicted device functionality; the particles were observed traveling in the expected zigzag mode. These experimental results are in strong agreement with finite element modeling, validating our design and fabrication process. Research presented in this paper was supported by the National Science Foundation under NSF EPSCoR Track-1 Cooperative Agreement OIA #1946202. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.