Point-of-care detection of hydroxyurea drug in serum using a supramolecular enzyme mimetic

Abstract

The sole approved therapeutic drug for sickle cell disease management is provided by hydroxyurea, requiring its precise detection and monitoring in biological matrices such as human blood serum for personalized treatment. Herein, we introduce a direct colorimetric detection method for hydroxyurea in serum using a metallo-supramolecular assembly called Vesi-ImCu that mimics the peroxidase enzyme. The Vesi-ImCu enzyme mimetic comprises a catalytically active copper center coordinated to synthetic imidazole containing surfactant and iminodiacetic acid capping moieties. By leveraging the peroxidase-like activity of Vesi-ImCu, we have demonstrated that it catalyzes the efficient production of nitric oxide from hydroxyurea that reacts with the Griess reagent, producing an intense pink color. This approach enables the naked-eye detection of hydroxyurea, with notable efficacy even in complex biological matrices such as human blood serum. The Vesi-ImCu suprazyme-based approach offers several advantages, including high sensitivity (limit of detection of 75 µM), clinically relevant dynamic range of hydroxyurea detection, minimum batch-to-batch variation, and the ability to perform mobile phone-based quantification. To our knowledge, this is the first report on direct colorimetric quantification of HU in serum. With its visual detection ability, high-end equipment-free quantification, user-friendliness and portability, the present enzyme mimetic holds great promise for point-of-care detection applications.