Surface-functionalized iron nanoparticles derived from Diospyros malabarica: Insights into interfacial properties for enhanced biosensing and bioactivity

Green synthesis strategies for nanomaterials prioritize environmental sustainability by utilizing biological agents for the reduction and stabilization of metal ions. In this work, we report the successful biosynthesis of iron nanoparticles (Fe-NPs) using an aqueous extract of Diospyros malabarica. The phytochemicals present in the extract facilitate regulated nucleation and surface functionalization, yielding equally dispersed nanoparticles with minimized agglomeration. Comprehensive characterization was performed using UV-visible spectroscopy, FTIR, TGA-DTA, XRD, SEM-EDX, and VSM. UV-visible absorption spectra exhibited a characteristic peak between 235-241 nm, confirming the formation of Fe-NPs. FTIR analysis verified the formation of Fe-O bonds and the presence of O-H, C-H, and C-O functional groups, indicating efficient organic capping by the bio-extract. TGA/DTA analysis revealed a 45% weight loss attributed to the degradation of moisture and bio-derived organic components. Morphological analysis via SEM showed spherical nanoparticles ranging from 20 to 60 nm, while XRD patterns confirmed well-crystallized, zero-valent bcc iron (α-Fe) with no detectable oxide phases. Magnetic characterization by VSM demonstrated superparamagnetic behavior, characterized by negligible remanence and coercivity. The synthesized Fe-NPs exhibited exceptional biosensing performance, alongside significant antibacterial, antioxidant, and anti-inflammatory activities. These findings highlight the potential of Diospyros malabarica-derived Fe-NPs as robust, multifunctional platforms for advanced biosensing and biomedical applications.