Green synthesis of zinc ferrite nanoparticles from Nyctanthes arbor-tristis: unveiling larvicidal potential, protein binding affinity and photocatalytic activities.

Environmental pollution, being a major concern worldwide, needs a unique and ecofriendly solution. To answer this, researchers are aiming in utilizing plant extracts for the synthesis of nanoparticles. These NPs synthesized using plant extracts provide a potential, environmentally benign technique for biological and photocatalytic applications. Especially, plant leaf extracts have been safe, inexpensive, and eco-friendly materials for the production of nanoparticles in a greener way. In this work, zinc ferrite nanoparticles (ZnFe₂O₄ NPs) were prepared using Nyctanthes arbor-tristis leaf extract by hydrothermal method, and its biological and photocatalytic properties were assessed. The synthesized ZnFe₂O₄ NPs were characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT-IR). X-ray diffraction confirmed the arrangement of the fcc crystal structure of the nanoparticles and that some organic substances were encapsulated within the zinc ferrite. According to the SEM analysis, the resulting nanoparticles got agglomerated and spherical in shape. The ZnFe₂O₄ nanoparticles are in their pure form, and all of their elemental compositions were shown by the energy-dispersive X-ray analysis (EDAX) spectrum. The FTIR results revealed that the produced nanoparticles contained distinctive functional groups. Fluorescence spectroscopy was used to examine the binding affinities between bovine serum albumin (BSA) and ZnFe₂O₄ nanoparticles in terms of protein binding, stability, and conformation. The interaction between BSA and ZnFe₂O₄ NPs was examined using steady-state and time-resolved fluorescence measurements, and it was evident that static quenching occurred. The ability of ZnFe₂O₄ nanoparticles to kill Culex quinquefasciatus (C. quinquefasciatus) larvae was evaluated. The synthesized NPs demonstrated a noteworthy toxic effect against the fourth instar larvae of C. quinquefasciatus with LC₅₀ values of 43.529 µg/mL and LC₉₀ values of 276.867 µg/mL. This study revealed the toxicity of green synthesized ZnFe₂O₄ NPs on mosquito larvae, proving that these NPs are good and effective larvicides. Furthermore, the ZnFe₂O₄ NPs were utilized for dye degradation of methylene blue under visible light treatment and achieved 99.5% degradation. [ABSTRACT FROM AUTHOR]