This period established the core paradigm that biofunctional nanoparticle interfaces are the primary levers for engaging biological systems. Researchers demonstrated surface-engineered nanoparticles capable of targeted cellular uptake, nucleic-acid–mediated gene regulation, and diagnostic readouts via Raman-active tagging. The convergence of advanced materials design with molecular readouts produced a cohesive framework that linked nanoparticle chemistry to translational imaging and diagnostics, foreshadowing integrated nanomedicine strategies.