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

This review summarizes recent advances in the development of chemically selective microspheres with a view to developing new, attractive methodologies in clinical and biomedical analysis. In particular, the development of fluorescent ion‐selective microspheres that function analogously to established bulk optodes is discussed. The fluorescent signal is dependent on a selective ion extraction process into a hydrophobic bulk phase doped with selective complexing agents. A mild preparation process for making large numbers of such microspheres is reported. Among a multitude of different applications, these beads may be applied in analytical flow cytometry in order to form part of a total bead‐based suspension array analysis system. Applications toward low detection limit measurements, as well as advances in polymer chemistry to develop plasticizer‐free ion sensing beads, are also discussed.