Continuous sheath‐free separation of drug‐treated human fungal pathogen Cryptococcus neoformans by morphology in biocompatible polymer solutions

Abstract

Cryptococcal meningitis caused by Cryptococcus neoformans is the leading cause of fungal central nervous system infections. Current antifungal treatments for cryptococcal infections are inadequate partly due to the occurrence of drug resistance. Recent studies indicate that the treatment of the azole drug fluconazole changes the morphology of C. neoformans to form enlarged "multimeras" that consist of three or more connected cells/buds. To analyze if these multimeric cells are a prerequisite for C. neoformans to acquire drug resistance, a tool capable of separating them from normal cells is critical. We extend our recently demonstrated sheath-free elasto-inertial particle separation technique to fractionate drug-treated C. neoformans cells by morphology in biocompatible polymer solutions. The separation performance is evaluated for both multimeric and normal cells in terms of three dimensionless metrics: efficiency, purity, and enrichment ratio. The effects of flow rate, polymer concentration, and microchannel height on cell separation are studied.

Viscoelastic Separation and Concentration of Fungi from Blood for Highly Sensitive Molecular Diagnostics

“…In our device, HA solution was chosen as the viscoelastic fluid with low viscosity (0.9 mPa·s) to achieve the high-throughput processing, compare to PEO solutions used in previous reports (2.3 mPa·s 51,52,54 and 4 mPa·s 53 ). Due to its cost effectiveness, it can be helpful to use PEO solution for the high-throughput processing in our device.…”

“…Additionally, in these devices, the flow at the bifurcation channel can affect the shear-sensitive cells. More recently, label-free and sheathless particle/cell separation in a straight microchannel with a low AR was demonstrated using a poly (ethylene oxide) (PEO) solution 51–54 . Particles laterally migrated toward the size- and shape-dependent equilibrium positions.…”

Sheathless Shape-Based Separation of Candida Albicans Using a Viscoelastic Non-Newtonian Fluid

“…With regard to shape-based separation of candida cells using our device, it was confirmed that separation efficiency is affected by asymmetry due to the shape of the formed germ tube. In other studies, the device enables the separation of cells based on shape differences without curvature, which can be a useful biomarker indicating cell type, cell cycle, and differences based on environmental conditions (e.g., fungal pathogens, microalgae, and rod-shaped bacteria (e.g., bacilli)) [34,46,47,68]. In addition, additional numerical analyses and simulations are required to calculate the elastic force exerted on nonspherical particles/cells and to predict the flow characteristics of those in the viscoelastic fluid.…”

“…Of late, viscoelastic microfluidics has been utilized to separate spherical and peanut-shaped microparticles based on shape differences [44,45]. In addition, a viscoelastic sheathless shape-based separation technique has been applied to drug-treated human fungal pathogens using differences in morphology [46]. However, there is still room for improvement in device throughput and applications to various biological particles with different shapes [34,47].…”

Manipulation of micro‐ and nanoparticles in viscoelastic fluid flows within microfluid systems

“…Faridi et al () combined elastoinertial effects for continuous separation of bacteria from undiluted blood with 76% efficiency. Furthermore, Li, Zielinski, Kozubowski, and Xuan () separated drug‐treated C. neoformans cells through straight rectangular microchannel using a sheath‐free elastoinertial solution. Li et al () employed VEF flows through a deterministic lateral displacement (DLD) array for particle sorting and separation (Figure f).…”