PHYTOGENIC SYNTHESIS OF MAGNETIC NANOZYMES FOR BIOMEDICAL DIAGNOSTICS AND MULTIFUNCTIONAL CATALYTIC APPLICATIONS
Keywords:
Index Terms—Biomedical diagnostics, Bio-inspired synthesis, Catalysis, Curry leaf (Murraya koenigii), Fe₃O₄ magnetic nanoparticles, Green nanotechnology, Magnetic nanozymes, Peroxidase-like activity.,,Abstract
The design of environmentally friendly nanomaterials that mimic enzyme activity has become
a fruitful approach to the development of biomedical diagnostics, biosensing and catalysis. In
the current study, magnetic Fe₃O₄ nanoparticles were synthesized using curry leaf (Murraya
koenigii) phytochemical extract as an eco-friendly reducing, stabilizing, and surface
functionalizing agent. The magnetic nanozymes formed from curry leaf extract were highly
crystalline, uniformly dispersed, and had a high catalytic activity due to the presence of
polyphenols, flavonoids, alkaloids and phenolic compounds. Synthesized nanozymes were
thoroughly characterized by UV–Visible spectroscopy, Fourier Transform Infrared
Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM),
Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDS), X
ray Photoelectron Spectroscopy (XPS), Vibrating Sample Magnetometry (VSM), and Dynamic
Light Scattering (DLS) to verify their structure, magnetic properties, surface chemistry, and
nanoscale morphology. The catalytic activity of the magnetic nanozymes was assessed by
measuring their peroxidase-like activity by using a chromogenic substrate (3,3′,5,5′
tetramethylbenzidine, TMB) and hydrogen peroxide (H₂O₂). The nanozymes showed rapid
substrate oxidation rate, high catalytic efficiency and excellent Michaelis–Menten kinetics,
indicating high affinity towards both TMB and H₂O₂. In addition, the nanozymes allowed
glucose to be sensitively detected by a glucose oxidase–nanozyme cascade system with a broad
linear detection range and low limit of detection, and good selectivity for glucose in complex
biological matrices. Furthermore, the nanozymes showed excellent catalytic degradation of
model organic dyes and the generation of reactive oxygen species (ROS), reinforcing all their
multifunctional catalytic properties. The synthesized magnetic nanozymes also exhibited
superior cytocompatibility with mammalian cells and more than 95% catalytic activity after
consecutive magnetic recovery cycles, with excellent structural stability and recyclability. At
the same time, the green synthesis, efficient catalytic performance, magnetic recoverability,
biocompatibility and enzyme-like activity make the curry leaf derived magnetic nanozymes as
highly promising multifunctional nanomaterials for point-of-care biomedical diagnostics,
biosensing, catalytic pollutant degradation, bioimaging, and sustainable nanobiotechnology. In
this work, a simple, eco-friendly and scalable approach to the development of next-generation
magnetic nanozymes with advanced biomedical and environmental applications is presented..
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