Reversible fluorescent solid porous films for detection of zinc ions in biological media

The need for a sensitive, selective, non-invasive and reversible fluorescent sensor for Zn²⁺ monitoring is addressed in this work. A novel guest-host system is developed, including a Zn²⁺ sensitive fluorescent probe, Zinpyr-1, embedded in a porous optically transparent hybrid film. The entrapped probe molecules are accessible and can interact with the external analyte. The immobilized Zinpyr-1 confirms its specificity and selectivity for Zn²⁺, as shown by sensing tests conducted in buffer solutions that mimic the ionic composition of biological media. The uniqueness of the developed sensor system lies in its reversibility, combined with a fast and selective response, allowing dynamic measurements of zinc concentrations in the 1 µM to 1 mM range within few tens of seconds. Unlike most Zn²⁺ sensors, this system is a film-based sensor, making it an interesting minimally invasive tool for future studies on how live cells cultured on it dynamically regulate the Zn²⁺ concentration under controlled physiological conditions.