Current advancements and future research directions in the green synthesis and applications of nanoparticles

The rapid expansion of research on green-synthesized nanoparticles (GSNPs), particularly those produced through biological processes, has generated a highly fragmented literature that obscures structural trends and translational gaps. This study conducts a comprehensive bibliometric analysis of publications indexed in Scopus between 2020 and 2025 to map the intellectual landscape of GSNPs and identify priority directions for future research. The findings demonstrate that silver nanoparticles (Ag NPs) dominate the field, driven by their established antibacterial effectiveness and broad biomedical and environmental utility. At the same time, plant extracts remain the primary biosynthetic resources, while alternative biological sources, including bacteria and fungi, are still inadequately investigated. The analysis also highlights the limited use of high-resolution characterization tools, including field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS), compared to the prevalent conventional techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), revealing a persistent characterization gap at the nano-bio interface. The geographic analysis highlights Asia, especially India and China, as leading contributors, supported by dense international collaboration networks. Conceptually, the study clarifies green synthesis within the 12 principles of green chemistry, integrating biological, physical, and chemical methods and proposing a taxonomy that resolves the frequent conflation of green synthesis with biosynthesis alone. Finally, by linking bibliometric patterns to toxicity and regulatory keywords, the analysis exposes key barriers to commercialization. It outlines research strategies to advance GSNPs toward scalable and regulation-ready nanotechnology platforms.