Biological synthesis, physico-chemical characterization of undoped and Co doped α-Fe ₂ O ₃ nanoparticles using <i>Tribulus terrestris</i> leaf extract and its antidiabetic, antimicrobial applications

Abstract

Abstract Hematite ( α -Fe 2 O 3 ) nanoparticles (NPs) were chemically and thermodynamically more stable among iron oxide nanoparticles. Doping of Co 2+ metal ion in α -Fe 2 O 3 can modify the structural, optical and magnetic properties of NPs and also enhances the potential of the biomedical applications. In the current study, undoped and Co doped hematite nanoparticles were synthesised by co-precipitation method using Tribulus terrestris L. leaf extract as bio-reductant. The magnetic, optical and structural investigations were studied with the help of Ultraviolet-visible (UV-Vis), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy equipped with Energy Dispersive X-ray (SEM-EDX) Spectroscopy, Vibrating Sample Magnetometer (VSM) and X-ray Diffraction (XRD) Spectroscopy. XRD analysis shows that synthesized nanoparticles were in hematite phase, rhombohedral in structure. XRD spectral pattern clearly evidenced that prepared α -Fe 2 O 3 and Co-Fe 2 O 3 NPs were highly crystalline with no impurity peaks. Using VSM spectra, the M-H curve indicates that saturation magnetisation (M s ) value increases for Co-Fe 2 O 3 NPs than undoped α -Fe 2 O 3 NPs, it can be clearly seen that doping largely affects the magnetic nature of nanoparticles. In the UV-Vis spectra, absorption maxima increases and band gap value decreases for cobalt doped hematite nanoparticles indicating the substitution of Fe 2+ ions by Co 2+ ions in α -Fe 2 O 3 lattice sites. Antidiabetic and antimicrobial activity of the synthesized undoped and Co doped hematite NPs were tested by alpha-amylase inhibitory and disc diffusion method. The Co-Fe 2 O 3 NPs have greatly inhibited the digestive enzyme and microbial strains as compared to undoped α -Fe 2 O 3 NPs.