Fabrication of Hematite (α-Fe2O3) nanoparticles under different spectral lights transforms physio chemical, biological, and nanozymatic properties

Fabrication of iron oxide (Fe₂O₃) nanoparticles (NPs) with different spectral lights was carried out to unveil the effect of change in the wavelength of Photons. NPs were synthesized by co-precipitation technique exposed to different light regimes (dark environment, daylight, and colored lights (blue, green, yellow, and red) from light emitting diodes (LEDs) at room temperature. X-ray diffractogram (XRD) analysis revealed that the synthesized NPs were hematite (α-Fe₂ O₃) with rhombohedral structure while scanning electron microscopic (SEM) study demonstrate the spherical and nano-disk like surface morphology. An increase in the size of NPs from 20.61 nm to 28.87 nm was observed with the increase in the wavelength of light. The elemental composition and surface chemistry of NPs were studied from energy-dispersive x-ray diffractive (EDX) and Fourier transform infrared spectroscopy (FT-IR) spectra. Maximum free radical quenching activity and total antioxidant potential were found by red light synthesized NPs (13.72%, and 36.72 ± 1.06 µg AAE/mg, respectively). The dark environment synthesized NPs had the maximum reduction potential (20.20 ± 0.4 µg AAE/mg). The highest metal chelating and cation radical scavenging was observed by blue light (41.48%) and daylight (9.71%) synthesized NPs respectively. α-Fe₂O₃ NPs showed significant enzyme inhibitory effects on urease, lipase, and alpha-amylase. The NPs also exhibited intrinsic peroxidase-like activity. Green and red light synthesized α-Fe₂O₃ NPs displayed the strongest antibacterial activity (12 mm) against Methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa respectively. This study is considered a novel step toward the synthesis of hematite (α-Fe₂O₃) NPs under LEDs with specific physio-chemical and biological properties to be employed in biological, environmental, and agricultural fields.