Water‐Dispersible BODIPY Multifunctionalized Silicon Oxide Nanoparticles for Glutathione Sensing

Abstract

Glutathione (GSH), a thiol containing small peptide, plays pivotal roles in maintaining cellular redox balance, metabolism, detoxification, and scavenging of free radicals. Aberrant GSH levels in cells and tissues are associated with various disorders, underscoring the importance of accurate GSH detection for clinical diagnosis and therapy monitoring. Several molecular probes have been designed as fluorescent-based GSH sensors. However, their water insolubility and the need of using organic cosolvents hinder their applicability on biological samples. Alternatively, nanomaterials have proven to be highly promising for boosting the precision of treatments and enhancing the accuracy of diagnosing diseases, thanks to their compatibility with biological environments and improved cell uptake. Here, the synthesis and characterization of a boron-dipyrromethene (BODIPY)-based probe (PB) are reported, incorporating a fluorescent BODIPY core, chlorine substituents for reaction with GSH, and a linking moiety for conjugation to the surface of silicon oxide nanoparticles (SONPs). Functionalized SONPs with PB are also characterized at the nanoscale using high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), Zeta potential, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), UV–Vis absorption, and fluorescence spectroscopies, confirming the surface functionalization and water-dispersibility of functionalized SONPs with PB. GSH sensing is evaluated in aqueous solution, conjugated to SONPs, and in living cells, showing promising potential for ratiometric GSH detection.