Sonochemical synthesis of graphene oxide-Ag2O nanozyme as an oxidize-like mimic for the highly sensitive detection of lithium in blood serum

Abstract

Bipolar disorder is commonly treated with lithium carbonate. The concentration of lithium in the blood serum should be closely monitored in patients who require long-term lithium therapy. To date, no colorimetric method of detecting lithium ions has been reported using nanosensors. We have developed a novel chemosensor based on nanozyme (NZ) to address this clinical need. The GO-Ag2O NZs were synthesized by a sonochemical method and used as a colorimetric nanosensor to detect lithium ions in human blood serum (Li (I)). To characterize NZs, various techniques were employed, including XRD, FTIR, TEM, FESEM, EDX, Raman spectroscopy, BET, DLS, Zeta potential, and ICP-OES. According to TEM and FESEM images of GO-Ag2O, the nanoparticles (NPs) of Ag2O are uniformly distributed on the surface of 2D graphene oxide sheets. In addition, silver oxide nanoparticles exhibited a cubic morphology with an average size of 3.5 nm. We have examined the performance of the NZs in an aqueous medium and in human blood serum that contains Li (I). A colorimetric test revealed that NZs synthesized in the presence of ultrasound were more sensitive to Li (I). According to the linearity of the calibration curves’ ranges, Li (I) has a limit of detection (LOD) of 0.01 µg/mL. Furthermore, it displayed a linear range between 0 and 12 µg/mL. GO-Ag2O NZs showed noticeable color changes from green to orange after exposure to Li (I). An incubation time of two minutes was found to be the most effective for sensing. This innovative approach provides a reliable method for monitoring lithium levels and ensuring patient safety during long-term lithium therapy for bipolar disorder.

Keywords

• Sonochemical synthesis
• Lithium (I) detection
• Graphene oxide
• Silvers oxide
• Nanozymes
• Biological fluids analysis