Tunable Ionic Mobility Filter for Depletion Zone Isotachophoresis

We present a novel concept of filtering based on depletion zone isotachophoresis (dzITP). In the micro/nanofluidic filter, compounds are separated according to isotachophoretic principles and simultaneously released selectively along a nanochannel-induced depletion zone. Thus, a tunable low-pass ionic mobility filter is realized. We demonstrate quantitative control of the release of fluorescent compounds through the filter using current and voltage actuation. Two modes of operation are presented. In continuous mode, supply, focusing, and separation are synchronized with continuous compound release, resulting in trapping of specific compounds. In pulsed mode, voltage pulses result in release of discrete zones. The dzITP filter was used to enhance detection of 6-carboxyfluorescein 4-fold over fluorescein, even though it had 250× lower starting concentration. Moreover, specific high-mobility analytes were extracted and enriched from diluted raw urine, using fluorescein as an ionic mobility cutoff marker and as a tracer for indirect detection. Tunable ionic filtering is a simple but essential addition to the capabilities of dzITP as a versatile toolkit for biochemical assays

Deformability Assessment of Waterborne Protozoa Using a Microfluidic-Enabled Force Microscopy Probe - Fig 1

<p>Oocyst measurement process <b>(a)</b> Schematic of FluidFM setup. <b>(b)</b> Typical force-distance curve showing zero (no contact), exponential (initial contact), and linear (hard contact) increase of force. <b>(c-e)</b> An oocyst (indicated by dashed blue oval) is selected, measured and released.</p

Cryptosporidium deformability - data

The files within the ZIP archive are in CSV format and can be readily accessed by Microsoft Excel, MATLAB, and many other programs. CSV files were recorded by the CyUI software from Cytosurge AG (Glattbrug, Switzerland). "spec.fwd.csv" and "spec.bwd.csv" files refer to the approach or retraction phases of the force spectroscopy measurements, respectively. Only the "spec.fwd.csv" (approach) files were used in the data analysis. Cantilever spring constants, deflection sensitivities, and sampling frequencies are specified in the header of the csv files. The initial cantilever-substrate separation was 10 micron for the C. muris and 5.0-5.3 micron for the C. parvum measurements

Height and spring constant data for untreated, heat-treated and freeze-thawed <i>C</i>. <i>parvum</i> oocysts obtained using FluidFM.

<p>Height <b>(a)</b> and spring constant <b>(b)</b> data for untreated (<i>n</i> = 184), heat-treated (<i>n</i> = 224) and freeze-thawed <i>C</i>. <i>parvum</i> oocysts (<i>n</i> = 131) are represented by boxplots which display medians and quartiles for the respective distributions; the upper and lower error bar caps are indicative of the maximum and minimum recorded values. *** Significantly different from untreated group (<i>p</i> < 0.001). ^## Significantly different from heat-treated group (<i>p</i> < 0.01). The distributions of height <b>(c)</b> and spring constant <b>(d)</b> are presented using histograms.</p

Height and deformability properties of untreated <i>C</i>. <i>muris</i> and <i>C</i>. <i>parvum</i> oocysts.

<p><b>(a)</b> Height and spring constant data that were obtained for each single assayed oocyst of <i>C</i>. <i>muris</i> (<i>n</i> = 56) and <i>C</i>. <i>parvum</i> (<i>n</i> = 71) are plotted together in a scatterplot and are accompanied by side histograms, which show the distributions of the spring constant <b>(b)</b> and height <b>(c)</b> independently. The human pathogenic <i>C</i>. <i>parvum</i> is indicated by grey and <i>C</i>. <i>muris</i> is indicated by black.</p