Fourier analysis to measure diffusion coefficients and resolve mixtures on a continuous electrophoresis chip

Kinetics of Reactive Modules Adds Discriminative Dimensions for Selective Cell Imaging

Living cells are chemical mixtures of exceptional interest and significance, whose investigation requires the development of powerful analytical tools fulfilling the demanding constraints resulting from their singular features. In particular, multiplexed observation of a large number of molecular targets with high spatiotemporal resolution appears highly desirable. One attractive road to address this analytical challenge relies on engaging the targets in reactions and exploiting the rich kinetic signature of the resulting reactive module, which originates from its topology and its rate constants. This review explores the various facets of this promising strategy. We first emphasize the singularity of the content of a living cell as a chemical mixture and suggest that its multiplexed observation is significant and timely. Then, we show that exploiting the kinetics of analytical processes is relevant to selectively detect a given analyte: upon perturbing the system, the kinetic window associated to response read-out has to be matched with that of the targeted reactive module. Eventually, we introduce the state-of-the-art of cell imaging exploiting protocols based on reaction kinetics and draw some promising perspectives.

Spatial waves in synthetic biochemical networks

We report the experimental observation of traveling concentration waves and spirals in a chemical reaction network built from the bottom up. The mechanism of the network is an oscillator of the predator-prey type, and this is the first time that predator-prey waves have been observed in the laboratory. The molecular encoding of the nonequilibrium behavior relies on small DNA oligonucleotides that enforce the network connectivity and three purified enzymes that control the reactivity. Wave velocities in the range 80-400 μm min(-1) were measured. A reaction-diffusion model in quantitative agreement with the experiments is proposed. Three fundamental parameters are easy to tune in nucleic acid reaction networks: the topology of the network, the rate constants of the individual reactions, and the diffusion coefficients of the individual species. For this reason, we expect such networks to bring unprecedented opportunities for assaying the principles of spatiotemporal order formation in chemistry.

From micro to macro: conversion of capillary electrophoretic separations of biomolecules and bioparticles to preparative free-flow electrophoresis scale

This invited contribution in the special issue of Electrophoresis published in celebration of the 30th Anniversary of this journal reflects the impact of our milestone paper [Prusík, Z., Kasicka, V., Mudra, P., Stepánek, J., Smékal, O., Hlavácek, J., Electrophoresis 1990, 11, 932-936] in the area of conversion of microscale analytical and micropreparative CE separations of biomolecules and bioparticles into (macro)preparative free-flow electrophoresis (FFE) scale on the basis of a correlation between CE and FFE methods. In addition to the survey of advances in the relatively narrow field of CE-FFE correlation and CE-FFE conversion, a comprehensive review of the recent developments of micropreparative CE and (macro)preparative FFE techniques is also presented and applications of these techniques to micro- and (macro)preparative separations and purifications of biomolecules and bioparticles are demonstrated. The review covers the period since the year of publication of the above paper, i.e. ca. the last 20 years.

Fourier transform to analyse reaction-diffusion dynamics in a microsystem

An integrated approach relying on a microsystem is introduced to easily extract, from a single experiment and with a global robust bi-exponential fit, an extensive set of thermodynamic, kinetic, and diffusion parameters governing associations in solution.