▎ 摘　　要

In this research work, the superparamagnetic graphene composites were produced by two parallel co-precipitation processes using the leaf extracts of Melia dubia and Prosopis juliflora. We also replaced the commercial graphite with the low-cost raw bio source, Pennisetum glaucum panicle waste for graphene oxide production. Magnetic nanoparticle with graphene oxide enhances the surface area with functionalization, high loading capacity, and good conductivity. The stability, colloidal dispersivity, particle size range, composition ratio of iron oxide to graphene oxide, and superparamagnetism were characterized by UV-visible spectrophotometer, powder X-ray diffraction (PXRD), Fourier transformation infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy dispersion X-ray (EDX and vibrating sample magnetometer (VSM), etc. Our composite reported better biocompatibility and cytotoxicity with less than 5% hemolysis of RBCs and up to 1 mu g concentration as a safer dosage from the MTT assay. Additionally, biofilm inhibition, antioxidant, and biocompatibility activities were confirmed for statistical significance with a p value (< 0.05) by two-way ANOVA balanced design method and the composite yield parameters were optimized by response surface method using central composite design. These unique properties enabled our sample to attenuate X-ray-CT imaging and MRI phantom imaging with better contrast, almost equivalent to the commercial agents. Thus, our results provide a new avenue for multimodality contrast applications and upon loading with suitable drug it may open up a new path for potential theranostic applications.