Biogenic Silver Nanoparticles via Microwave‐Assisted Green Synthesis: Antimicrobial Agents and Fluorescent Nanosensors for the Sensitive Determination of Entacapone and Thiopental in Human Plasma and Dosage Forms

Abstract

In this work, silver nanoparticles (Ag-NPs) were developed as sensitive fluorescent nanoprobes for the assay of entacapone and thiopental, for the first time. Ag-NPs were synthesized via an ultrafast microwave-assisted green method in only 30 s using Lupinus albus seed extract as a natural reducing agent. The prepared Ag-NPs were characterized using high-resolution transmission electron microscope, dynamic light scattering, energy-dispersive X-ray spectroscopy, Fourier transform infrared, UV-visible spectrophotometry, and spectrofluorimetry. They exhibited strong intrinsic fluorescence at 360 nm upon excitation at 280 nm, with a mean particle size of 38.3 nm and a polydispersity index of 0.202. The native fluorescence of Ag-NPs was selectively quenched by entacapone and thiopental over concentration ranges of 0.8-10.0 and 5.0-20.0 μM, with detection limits of 0.07 and 0.52 μM, respectively. The proposed nanosensor was successfully applied for the determination of both drugs in pharmaceutical dosage forms and spiked human plasma. In addition to their analytical performance, the synthesized Ag-NPs demonstrated significant antimicrobial activity against one fungal strain and four bacterial strains. This dual functionality highlights their potential as a multifunctional theranostic detect-and-treat nanoplatform integrating diagnostic sensing with antimicrobial action. The greenness of the method was assessed using AGSA and ComplexMoGAPI tools, and the method was validated according to ICH Q2(R2) guidelines.