Plasmonic Evaluation and Anticancer Potential of Gold Nanoparticles Synthesised via Sonochemical Route from Plum Peel Waste

The integration of sustainable nanomaterials with advanced optical functionalities is essential for the development of next-generation biomedical devices. This study reports the ultrasound-assisted green synthesis of plasmonic gold nanoparticles (AuNPs) using Prunus salicina (plum) peel extract a novel approach that valorises food waste for the production of high-value nanomaterials. The synthesised AuNPs were comprehensively characterised using UV–visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX). UV-Vis analysis revealed a distinct surface plasmon resonance (SPR) peak at 538 nm, confirming successful nanoparticle formation, with optical tunability influenced by sonication time. The AuNPs exhibited excellent stability (zeta potential: −34 mV) and a predominantly spherical morphology, with an average hydrodynamic size of 41 nm. FESEM confirmed their uniform distribution, while EDX validated the elemental composition. In addition, in vitro cytotoxicity studies using the MCF-7 human breast cancer cell line demonstrated dose-dependent anticancer activity, underscoring the biomedical potential of the synthesised nanoparticles. This work establishes a green, rapid and scalable route for producing optically functional AuNPs with promising applications in plasmonic biosensing, photothermal therapy and other biomedical fields.