nanoparticles in drilling fluids and environmental applications: fundamentals, classification, and characterization

Nanomaterials-particularly nanoparticles-have garnered significant attention across scientific and industrial domains owing to their distinct physicochemical attributes. their exceptionally high surface area-to-volume ratio, controllable reactivity, and modifiable optical, electrical, and magnetic properties render them suitable for a wide range of applications, spanning from drug delivery and diagnostics to advanced drilling fluid engineering, where they can improve stability under harsh subsurface conditions. such features have enabled innovative applications in diverse fields, including medicine, electronics, energy storage, environmental remediation, catalysis, agriculture, and the food industry. among recent developments, the biological synthesis of nanoparticles using plant extracts and microorganisms has emerged as a sustainable and eco-friendly approach that reduces both production costs and environmental hazards associated with traditional methods. this review provides an in-depth discussion of nanoparticle classifications, physicochemical features, and general approaches to their evaluation. furthermore, it outlines the key differences in behavior and functionality of materials at the nanoscale, offering useful insight into their performance. several case studies involving biologically synthesized nanoparticles and their applications are presented to demonstrate their potential across various sectors, offering practical guidance for researchers aiming to adopt green synthesis strategies in their investigations.