Laser-Assisted Green Synthesis of Silver Nanoparticles for Ferric Ion Detection

Abstract

In the present study, we report a rapid, single-step, room-temperature laser-assisted green synthesis method for the development of functional silver nanocomposites designed for Fe³⁺ ion detection. The nanocomposites were synthesized by irradiating silver precursor solutions containing natural biopolymer stabilizers, which simultaneously acted as reducing and capping agents. Under mild and environmentally benign conditions, laser-induced photoreduction converted Ag⁺ ions into silver nanoparticles, while the stabilizing biomolecules underwent self-assembly to encapsulate the newly formed particles, producing uniformly dispersed AgNP-based nanocomposites. The entire process required no toxic chemicals, organic solvents, or specialized chemical reducing agents, relying solely on laser energy and green stabilizers to drive nanoparticle formation. Characterization of the optimized nanocomposites confirmed the successful synthesis of fine, nearly spherical particles with a narrow size distribution and a robust biopolymer capping layer, enhancing colloidal stability. The nanocomposites enabled instrument-free visual detection of Fe³⁺ ions, where Fe³⁺–biopolymer coordination triggered rapid nanoparticle aggregation with a distinct color change. The detection system demonstrated a visual detection limit of approximately 20 μM, while UV–Vis and SEM analyses further verified aggregate formation upon Fe³⁺ addition. Owing to their strong surface plasmon resonance response, excellent colloidal stability, and environmentally friendly synthesis route, the prepared nanocomposites exhibit significant potential for large-scale applications in environmental sensing, medical diagnostics, and water-quality monitoring. In addition, the AgNP-based nanocomposites displayed potent antibacterial activity against Escherichia coli and Staphylococcus aureus, along with notable antifungal and antiviral properties, underscoring their multifunctional nature.