Fluorescence "light-up" sensor based on ligand/SiO₂@NH₂@cyanuric chloride nanoparticle interactions in alliance with...

Berberine (BBR) is an important anti-inflammatory drug for the treatment of intestinal diseases. The quantification of BBR is required in clinical medicine because long-term or excessive intake can lead to drug resistance and adverse effects. In this study, SiO₂@NH₂@cyanuric chloride (CNCl) nanoparticles (NPs) were successfully prepared by covalently incorporating CNCl onto the surface of SiO₂ NPs. Furthermore, a novel fluorescence "light-up" sensor for assaying BBR was established based on the interaction between BBR and SiO₂@NH₂@CNCl NPs. Although BBR was non-emissive in aqueous media, its fluorescence was considerably augmented because of the interaction with the as-prepared SiO₂@NH₂@CNCl NPs, and the enhancement factor was approximately three times larger than that of pure SiO₂ NPs. Compared with SiO₂ NPs, SiO₂@NH₂@CNCl NPs can interact with BBR through electrostatic interactions and π-π stacking. These interactions restricted the intramolecular motion and charge transfer of BBR, resulting in fluorescence enhancement. The sensor was sensitive, with a linear response over a concentration range of 25-2500 nM (R² = 0.9905) and a detection limit (3σ/k) of 4.7 nM, and it had good selectivity for BBR in the presence of bovine serum albumin, amino acids, and metal ions. When the sensor was applied to real serum samples, rapid extraction and salt dehydration occurred to improve the efficiency of pretreatment, and satisfactory standard recovery rates (95%-96%) were achieved even when only small amounts of acetonitrile was used for protein precipitation. This strategy could serve as a reference for other studies requiring the analysis of drugs in biological samples.