Nanoengineered polyelectrolyte microcapsules as fluorescent potassium ion sensors

Nanoengineered hollow polyelectrolyte microshells have been fabricated for use as real-time in vitro and in vivo fluorescent potassium ion biosensors. The microshells are fabricated using the electrostatic layer-by-layer (LbL) method to assemble polyelectrolyte multilayers on dissolvable latex microparticle templates, and then are "loaded" with the fluorescent potassium indicator potassium-binding benzofuran isophthalate (PBFI). The microshells then serve to protect the sensor chemistry from the environment and vice versa, while still allowing small analyte molecules to pass freely through the shell walls. The shells have been successfully loaded with PBFI, and sensor response has been assessed with excellent results. Microsensors such as these may be very useful tools in medical diagnostics and biological research.