A novel synthesis of hybrid graphene oxide as a dual-functional fluorescent chemosensor for Ti ⁴⁺ ion detection and antibacterial performance <i>via</i> simultaneous oxidation and functionalization

Functionalized graphene oxide (GO), a versatile two-dimensional material, is synthesized by surface modification and exhibits remarkable physical and chemical properties, making it attractive for a wide range of applications. In this work, we present a unique one-step approach that simultaneously oxidizes and functionalizes graphite using <i>Calotropis gigantea</i> latex as a natural reagent. The latex functions as an oxidizing and functionalizing agent, introducing bioactive compounds and oxygen- and nitrogen-rich functional groups onto the GO surface under ambient conditions (Bio@HGO). This method minimizes the use of hazardous reagents and introduces a high density of surface functional groups on GO sheets suitable for metal ion interactions. The synthesized material was characterized using PXRD, FE-SEM, XPS, Raman, FTIR, and BET analyses to confirm the successful functionalization by using natural latex. The introduction of oxygenated and nitrogen-containing groups from <i>Calotropis gigantea</i> latex is found to improve dispersion stability and enhance the affinity for Ti⁴⁺ metal ion detection. Electrochemical investigations have confirmed that the material exhibits high sensitivity and selectivity towards Ti⁴⁺ ions, with a distinguishable and measurable response in the given experimental concentration range. This work highlights the potential of <i>Calotropis gigantea</i> latex-derived materials for the development of graphene-based sensors, offering a sustainable route for environmental monitoring of toxic metals such as Ti⁴⁺. In addition, the potential antibacterial activity of Bio@HGO was also confirmed against <i>Pseudomonas aeruginosa</i> and <i>Escherichia coli</i> bacteria, with zones of inhibition of 0.95, 1.57, and 1.90 mm and 1.25, 1.45, and 2.15 mm at 20, 40, and 80 μg mL^-1 concentrations of Bio@HGO, respectively.