Synthesis of Diboronic Acid-Based Fluorescent Probes for the Sensitive Detection of Glucose in Aqueous Media and Biological Matrices

Reliable and accurate glucose detection in biological samples is of great importance in clinical diagnosis and medical research. Chemical probes are advantageous in simple operation and flexible design, especially for the development of fluorescent probes. Anthracene-based diboronic acid (P-DBA) has shown potential in glucose probing because of its high sensitivity. However, poor solubility limits its applications in aqueous media. In this work, we systemically modify P-DBA by introducing fluoro (F-), chloro (Cl-), methoxyl (MeO-), or cyano (CN-) substituents. Among these probes, the cyano-substituted probe (CN-DBA) displays the highest glucose-binding constant (6489.5 M^-1, 33% MeOH). More importantly, it shows good water solubility in the aqueous solution (0.5% MeOH), with ultrasensitive recognition with glucose (LOD = 1.51 μM) and robust sensing from pH 6.0 to 9.0. Based on these features, the CN-DBA is finally applied to detect glucose in cell lysates and plasma, with satisfactory recovery and precision. These results demonstrate that CN-DBA could serve as an accurate, sensitive fluorescent probe for glucose assays in biological samples.