The era foregrounded the design of multifunctional nanoscale carriers that blend polymeric, liposomal, micellar, and inorganic porous architectures to achieve extended systemic circulation, targeted tissue accumulation, and controlled release. Researchers pursued monodispersity, surface engineering for stealth, and stimuli-responsive triggers such as intracellular pH to enable endosomal escape. Methodologies emphasized modular synthesis, robust characterization, and strategies for translational viability, including compatibility with clinical manufacturing and safety profiles.