Viscoelastic particle enrichment using a 3D-printed enrichment device

Sample enrichment is of paramount importance in studying complex cell populations such as blood cells, stem cells, and bacterial communities, as it enables to increase the concentration of target cells, enhances detection sensitivity for low-abundance members, and reduces interference from non-target components. Current enrichment techniques face limitations regarding modularity, dynamic size range, and design complexity. Here, we present a feasibility study using projection micro-stereolithography 3D-printing technology to demonstrate a microfluidic device for size-based particle separation and enrichment. This device leverages the advantages of viscoelastic flow focusing and integrates a 3D-printed reverse nozzle with fused silica microcapillaries, thus enabling separating flow-focused particles of a specific size cutoff and their background. By varying the inlet capillary inner diameter, our device demonstrates tunable separation capabilities, as illustrated using polystyrene microparticles (1–10 μ m). Pilot experiments further show its applicability for enriching algae and stem cells from bacterial contaminants. With its low cost, rapid fabrication, modularity, and dual-outlet design that enables simultaneous collection of both target cells and contaminants, the 3D-printed microfluidic device offers a cost-effective alternative for a range of diagnostic and preparative applications. • 3D-printed microfluidic device enables viscoelastic particle focusing and separation. • Size selectivitiy is tuned by capillary dimensions offering modular size separation. • Reverse nozzle with fused silica capillaries drives passive and continuous operation. • Dual outlets provide enriched large cells in one outlet contaminants in another. • Validated with beads, bacteria-algae mixes, and stem cells spiked with bacteria.