Flow Cytometric Ion Detection with Plasticized Poly(Vinyl Chloride) Microspheres Containing Selective Ionophores

Abstract

The use of flow cytometry as a rapid, high-throughput diagnostic tool for the analysis of ions is described. Monodisperse, uniform microspheres, which obey bulk optode theory and are governed by bulk extraction processes rather than surface phenomena, were prepared under mild, nonreactive conditions using a sonic stream particle casting apparatus. As an initial example demonstrating the utility of this approach, microspheres that contained a H+-selective fluorescent chromoionophore (ETH 5294), a cation-exchanger (NaTFPB), and either a highly sodium-selective (sodium ionophore X) or a potassium-selective ionophore (BME-44) were prepared. Separate solution analysis of sodium- and potassium-selective microspheres resulted in the generation of functional response curves using peak channel fluorescence intensities. The selectivity observed for both types of particles is sufficient for the clinical determination of Na+ and K+. Furthermore, sodium- and potassium-selective microspheres were analyzed in parallel using sodium sample solutions, resulting in the successful determination of sodium ion concentrations and providing important information about the selectivity of the potassium-selective sensors over sodium. This work demonstrates the potential applicability of flow cytometry as a means for developing multiplexed, rapid, high-throughput analyses for clinically relevant ions.

Microfluidic ion-sensing devices

“…Such microspheres have been utilized for silver and iodide analysis after immobilizing them on the tips of etched optical fibers [85,86]. More importantly, the particles also have been employed for the analysis of sodium, potassium, and calcium in a flow cytometry set-up [83,87,88]. These cytometric studies demonstrate that microsphere optodes are amenable to fluidic manipulation and analysis in a dynamic system much like that encountered in microfluidics.…”

Cytométrie en flux, microbilles et analyses biomoléculaires multiplexes

“…En virologie et en bactériolo-gie, des agents infectieux ont également pu être caractérisés et mis en évidence dans différents liquides biologiques [6,33,39,40,42] grâce à ces nouvelles techniques multiplexes qui sont de ce fait particulièrement attractives dans le cadre de la biosurveillance nécessitant de disposer de méthodolo-gie capables d'appréhender rapidement, simplement et avec fiabilité plusieurs pathogènes [13]. Des identifications simultanées de macrominéraux essentiels tels que les ions sodium et potassium, impliqués dans le contrôle du volume plasmatique, l'équilibre acidobasique, la fonction nerveuse et musculaire, ont aussi été réalisées par cytométrie en flux avec des microbilles en polychlorure de vinyle couplées à des ionophores sélectifs [27].…”

Fluorescent Ion‐Sensing Microspheres for Multiplexed Chemical Analysis of Clinical and Biological Samples

“…The final application, however, is to demonstrate that flow cytometry can be used to measure ions in clinical samples. As a precursor to that final goal, it was necessary to demonstrate that parallel analysis of different subsets of microspheres is possible in aqueous solution [86]. In microsphere-based flow cytometry, particles are hydrodynamically focused in single file order and illuminated by a laser (Figure 1.3.6).…”