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.